IVI STEP YPES - National Instruments©National Instruments Corporation 5 IVI Step Types Editing an...

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370361A-01 Copyright © 2001 National Instruments Corp. All rights reserved. March 2001

IVI STEP TYPESThis document describes the set of IVI step types that TestStand provides.First, the document discusses how to use the IVI step types and how to editIVI steps. Next, the document describes the functionality of each of the IVIstep types.

ContentsOverview................................................................................................. 3Editing an IVI Step ................................................................................. 5

Expression Controls ......................................................................... 6Extensions ........................................................................................ 7Operation Settings............................................................................ 8Validating a Configuration .............................................................. 9Using Soft Front Panels ................................................................... 10Get Information................................................................................ 13Instrument Session Manager............................................................ 13

IVI Dmm Step......................................................................................... 13Configure ......................................................................................... 14

Basic Tab .................................................................................. 14Advanced Tab........................................................................... 18Temperature Tab....................................................................... 23Extensions Tab ......................................................................... 26Operation Settings Tab ............................................................. 27

Read and Fetch................................................................................. 27Initiate .............................................................................................. 29Abort ................................................................................................ 29Send SW Trigger ............................................................................. 29Get Information................................................................................ 29Step Properties ................................................................................. 31

IVI Scope Step ........................................................................................ 32Configure ......................................................................................... 33

Basic Tab .................................................................................. 33Advanced Tab........................................................................... 36Channels Tab ............................................................................ 37Trigger Tab ............................................................................... 39

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IVI Step Types 2 ni.com

Extensions Tab ..........................................................................46Operation Settings Tab..............................................................48

Read and Fetch .................................................................................48Channels Tab.............................................................................49Operation Settings Tab..............................................................52

Initiate...............................................................................................52Abort.................................................................................................52Auto Setup ........................................................................................53Get Information ................................................................................53Step Properties..................................................................................55

IVI Fgen Step...........................................................................................56Configure..........................................................................................57

Basic Tab...................................................................................57Channels Tab.............................................................................60Waveforms Tab .........................................................................65Sequences Tab...........................................................................68Extensions Tab ..........................................................................69Operation Settings Tab..............................................................70

Initiate...............................................................................................70Abort.................................................................................................71Send Software Trigger......................................................................72Get Information ................................................................................72Step Properties..................................................................................74

IVI DC Power Supply Step .....................................................................75Configure..........................................................................................76

Channels Tab.............................................................................76Extensions Tab ..........................................................................80Operation Settings Tab..............................................................81

Measure ............................................................................................81Channels Tab.............................................................................82

Initiate...............................................................................................83Abort.................................................................................................83

Send Software Trigger ..............................................................83Reset Output Protection....................................................................83Get Information ................................................................................84Step Properties..................................................................................87

IVI Tools Step .........................................................................................88Get Session Info ...............................................................................88Init.....................................................................................................90Close .................................................................................................91Reset .................................................................................................91Self Test............................................................................................91Revision Query.................................................................................93Error Query.......................................................................................93Get Error Info ...................................................................................95Set/Get/Check Attributes..................................................................96

© National Instruments Corporation 3 IVI Step Types

Step Properties ................................................................................. 98

OverviewTestStand provides several step types that enable you to configure andacquire data from IVI class compliant instruments. IVI is an instrumentdriver standard that provides common programming interfaces for severalclasses of instruments. IVI drivers exist for a number of popularinstruments, including all applicable devices from National Instruments.For more information on IVI and IVI class compliant instrument drivers,see the National Instruments web site at ni.com

TestStand includes the following IVI step types:

• Dmm—Performs single-point and multipoint measurements withdigital multimeters.

• Scope—Performs single-point and waveform measurements withoscilloscopes.

• Fgen—Generates predefined or custom waveforms using arbitrarywaveform generators.

• DCPower—Controls and monitors the output of DC power supplies.

• Tools—Sets or gets instrument attributes and performs utilityoperations on any IVI instrument.

IVI step types offer a configuration-based approach to instrument control.Typically, you use an initial step to configure an instrument and thenperform measurements in one or more subsequent steps. TestStandreferences a session to an instrument using the instrument logical name.TestStand automatically initializes the instrument session when theinstrument is first configured and automatically closes the instrumentsession when the execution is closed. If two executions reference the samelogical name, the session is shared and the session closes when the lastexecution is released.

To support the IVI step types, TestStand installs VISA, Measurement andAutomation Explorer (MAX), and a set of basic IVI class drivers. TestStandinstalls one specific driver for each instrument class so that you can usespecific driver simulation when your development machine does notconnect to instruments.

Note The basic class drivers do not support class level simulation or IVI class level APIspying. To obtain fully functional IVI class drivers and a complete set of specific drivers,you can purchase version 1.1 or later of the IVI driver toolset. You can also download IVIspecific drivers from ni.com


Measurement & Automation Explorer (MAX) provides access to theNational Instruments DAQ, GPIB, IMAQ, IVI, Motion, VISA, and VXIdevices. Measurement & Automation Explorer allows you to configureyour National Instruments hardware and software, add new channels,interfaces, and virtual instruments, execute system diagnostics, and viewdevices and instruments connected to your system. By default TestStandconfigures a sample logical name for each IVI class. The following figureshows the default IVI instruments defined in MAX.

IVI step types complement but do not replace the instrument configurationand measurement operations you perform in code modules that you writeusing LabVIEW, Measurement Studio, Visual Basic, or other tools.Although IVI step types are the easiest way to configure and acquire datafrom IVI class instruments, you must use code modules to controlinstruments under the following circumstances:

• You need to precisely specify the instrument driver calls to ensureoptimal performance.

• You need to call specific driver functions that an IVI class does notsupport.

• Your instrument does not conform to an IVI class or does not have anIVI driver.

• You need to interleave your instrument control operations with othercode that must reside in a single code module.


Editing an IVI StepTo use an IVI step, insert an IVI step for the class of instrument you wantto control. To edit the step, right-click on the step and select Edit from thecontext menu. The following figure shows the Configure operation for theIVI Dmm step.

Figure 1. Edit Dmm Step Dialog Box

Each edit step dialog box contains a Logical Name control. The controlselects a logical name or a virtual instrument name that you configure inMeasurement and Automation Explorer (MAX). You can use the buttons tothe right of the control to display the Browse for Expression dialog box andto launch Measurement and Automation Explorer.

Each edit step dialog box contains an Operation control. The controlspecifies the action the step performs. Typical operations includeconfiguring the instrument, taking a reading, or showing or hiding agraphical display panel for the instrument, also called a soft front panel.Depending on the instrument, you can also select other lower level actions


such as Initiate, Send Software Trigger, or retrieve state information fromthe instrument.

When you select an operation, the area under the operation control changes.Many operations group their settings on tab controls.

In some cases, when TestStand configures an instrument, the instrumentdriver may coerce a settings value. Configuring an instrument might resultin an invalid value error for a particular setting because theinstrument-based values are not checked for validity until the configurationactually occurs. Once configure completes successfully, you can issue allof the other operations in subsequent steps.

Expression ControlsMost controls for settings accept expressions so you can either specify aliteral value or an expression with variables and properties that TestStandevaluates at runtime. If you leave the expression empty, the operation doesnot update the setting value. This can be useful if you previouslyconfigured an instrument and all you want to do is change a few specificsettings.

You can use the browse button to the right of each control to display theBrowse for Expression dialog box. Some expression controls use a ringcontrol, which contains commonly used values. When you select an itemfrom the ring, the control automatically displays the selected value.

Many of the setting controls automatically check your expressions. Oncethe control looses focus, the control highlights syntax errors with redstrikethrough text, and evaluation or type mismatch errors with red text.To display the error details, you can use the mouse to review the tooltip forthe control as shown in the following figure.


ExtensionsThe configure operation configures the instrument to match the settings asspecified by the step. To enable instrument configuration controls thatapply to features that IVI defines as class extensions, select from theExtensions tab the extended features that your instrument supports.The following figure shows the Extensions tab for the IVI Dmm step.

Figure 2. Dmm Class Extension Tab

The configure operation handles only those settings that are supported bythe base class specification and the extension groups specified on theExtensions tab. For best results, enable only those extensions that arerequired for your application.


Operation SettingsMany of the operations, such as Configure and Fetch, allow you to specifywhere the dialog saves the operation settings for the step. For example, youcould save the configure settings in a shared variable so that multiple stepscould use the same settings. The following figure shows the OperationSettings tab for the configure operation.

The Configuration Source control specifies the name of the property orvariable where TestStand stores the settings when you select the OKbutton. The Load button reloads the settings from the specified property orvariable location.


Validating a ConfigurationWhen you edit a step that configures an instrument, you can use theValidate button to test your configuration before closing the edit dialogbox. For the IVI Dmm step type, the Validate button displays the followingdialog box.

The Validate IVI Configuration dialog box contains the following controls:

• Logical Name—Selects a logical name or a virtual instrument namethat you configure in Measurement and Automation Explorer (MAX).

• Configure Attributes—Lists the settings to validate with theinstrument. The Expression and Value controls display the settings forthe currently selected setting.

• Show All—When unchecked, the list control displays only theexpressions that could not be evaluated. When checked, the list controldisplays all settings.

• Init—Opens an IVI session to a virtual instrument. The Simulatecheckbox specifies whether the instrument session uses simulationinstead of talking directly to the instrument.

• Close—Closes the instrument session.

• Reset—Places the instrument in a known state by sending thecommand string “*RST” to the instrument.

• Configure—Configures the instrument to match the state as specifiedby the specified settings.

• Show Soft Front Panel—Displays the instrument soft front panel sothat you can directly interact with the instrument.


Using Soft Front PanelsEach IVI session for an IVI step type can display a graphical display panelfor the instrument, also called a soft front panel. The show and hide softfront panel operations control whether TestStand displays a soft front panelfor the instrument. The following figure shows the soft front panel for theIVI Scope step.

Figure 3. IVI Scope Step Soft Front Panel

When the soft front panel is visible, you can interact directly with theinstrument session that TestStand is controlling.


The following figure shows the SFP Options tab for the Show Soft FrontPanel operation.

The SFP Options tab for the Show Soft Front Panel operation contains thefollowing controls:

• Allow Control—Specifies whether the soft front panel responds touser input.

• Automatically Close Window When Execution isReleased—Specifies whether the soft front panel is closed when theexecution is released. If not, the instrument session remains open untilthe soft front panel is closed.

• Allow User to Close—Specifies whether the user can close the softfront panel window.


• Wait for User to Close Before Continuing—Specifies whether theexecution waits for the soft front panel to close before continuing to thenext step.

• Auto Read Interval—Specifies the rate at which the soft front panelreads or fetches measurements to update its display. This settingapplies to the Dmm, Scope and DC Power Supply step types.

The following figure shows the SFP Options tab for the Show Soft FrontPanel operation.

The Window Options tab for the Show Soft Front Panel operation containsthe following controls:

• Window Title—Specifies the title to display on the soft front panelwindow.

• Location—Specifies the location and size of the soft front panelwindow.

• Show Modal—Specifies that the soft front panel window is modal tothe main application window.


The Operations Settings tab specifies to which property or variable the stepsaves the soft front panel operation settings to when closing the edit dialog,and reloads the operation settings when displaying the edit dialog.

Get InformationYou can use the Get Information operation for each instrument class steptype to retrieve low-level status and information from the instrument. Forthe Get Information tab you must specify an expression that contains avariable or property to which the step assigns the retrieved value. In somecases, you must specify a channel name for the value to retrieve.

Instrument Session ManagerIVI step types use a software component called the Session Manager toshare named instrument connections. You can use the Session Manager toshare instrument connections in code modules that you write, even if youdo not use IVI step types. For more information about the Session Manager,refer to the Session Manager help file in the National Instruments sectionof the Windows Start menu.

Note Currently available drivers do not allow you to use the same instrument driversession in more than one operating system process simultaneously.

IVI Dmm StepYou use the IVI Dmm step type to perform single-point and multipointmeasurements with digital multimeters. The step type supports thefollowing operations:

• Configure—Configures the instrument to match the state as specifiedby the step.

• Show Soft Front Panel—Displays the soft front panel for theinstrument.

• Hide Soft Front Panel—Hides the soft front panel for the instrument.

• Read—Initiates and returns a measurement from an instrument.

• Initiate—Initiates a measurement.

• Fetch—Returns the measured value from a measurement that theInitiate operation has started.

• Abort—Cancels the wait for a trigger.

• Send SW Trigger—Sends a software trigger command to trigger theinstrument.

• Get Information—Retrieves low-level status and information fromthe instrument.


ConfigureThe Configure operation configures the instrument to match the instrumentstate as specified by the step.

Basic TabThe following figure shows the Basic tab for the Configure operation.

The Basic tab for the Configure operation contains the following controls:

• Measurement Function—Specifies the measurement function. Thevalue of this setting determines the units for the Range and Resolutionsettings and the measurement values returned by the Read and Fetchoperations.

Supported values:

DC Volts (1) Sets the DMM to measure DC voltage.

AC Volts (2) Sets the DMM to measure AC voltage.

DC Current (3) Sets the DMM to measure DC current.


AC Current (4) Sets the DMM to measure AC current.

Resistance 2-wire (5) Sets the DMM to measure 2-wireresistance.

Resistance 4-wire (101) Sets the DMM to measure 4-wireresistance.

AC Plus DC Volts (106) Sets the DMM to measure AC voltage plusDC voltage.

AC Plus DC Current (107)Sets the DMM to measure AC current plusDC current.

• Resolution—Specifies the measurement resolution in absolute unitsof precision. The Measurement Function setting determines the unitsfor resolution. If the Resolution value that you specify does not exactlymatch a value supported by an instrument driver, the instrument driverwill coerce down to the next supported value. The digits of precisioncan be calculated from the Range and Resolution properties:

Precision = Log10(Range/Resolution).

• Min AC Freq—Specifies the minimum frequency component (inHertz) of the input signal for AC measurements. If AC Min Freq doesnot exactly match a supported value by an instrument driver, theinstrument driver will coerce down to the next supported value. Thevalue of this setting affects instrument behavior only when theMeasurement Function setting is set to an AC voltage or AC currentmeasurement and the AC Measurement extension is enabled.

• Max AC Freq—Specifies the maximum frequency component (inHertz) of the input signal for AC measurements. If AC Max Freq doesnot exactly match a supported value by an instrument driver, theinstrument driver will coerce up to the next supported value. The valueof this setting affects instrument behavior only when the MeasurementFunction setting is set to an AC voltage or AC current measurementand the AC Measurement extension is enabled.

• Trigger Source—Specifies the trigger source. You can use a trigger tocontrol when the DMM takes its measurement. The trigger’s locationis defined by the Trigger Source setting.

Supported values:

Immediate (1) Specifies that the DMM does not wait for atrigger before taking a measurement.

External (2) Specifies that the DMM waits for a triggeron the external trigger input before taking ameasurement.

Software ( 3) Specifies that the DMM waits for a triggeruntil Send Software Trigger operationexecutes and then takes a measurement.


TTL0 (111) Specifies that the DMM waits for a triggeron TTL0 before taking a measurement.








ECL0 (119) Specifies that the DMM waits for a triggeron ECL0 before taking a measurement.

ECL1 (120) Specifies that the DMM waits for a triggeron ECL1 before taking a measurement.

PXI STAR (131) Specifies that the DMM waits for a triggeron the PXI Star trigger bus before taking ameasurement.

RTSI0 (140) Specifies that the DMM waits for a triggeron RTSI0 before taking a measurement.







• Range—Specifies the measurement range. The Range setting is usedonly when the Range Mode setting is set to Use Specified Range. IfRange value that you specify does not exactly match a supported valueby an instrument driver, the instrument driver will coerce up to the next


supported value. The Measurement Function setting determines theunits of Range. The digits of precision can be calculated from theRange and Resolution properties:

Precision = Log10(Range/Resolution).

Supported values:

Auto Range On (–1) Sets the DMM to calculate the range beforeeach measurement automatically.

Auto Range Off (–2) Disables autoranging. The DMM sets therange to the value it most recentlycalculated.

Auto Range Once (–3) Sets the DMM to calculate the range beforethe next measurement. The DMM uses thisrange value for all subsequentmeasurements.

Use Specified Delay (0) Enables you to manually specify themeasurement range.

• Trigger Delay—Specifies the length of time in seconds between theDMM receiving the trigger and taking the measurement. Many DMMshave a small, nonzero value as the minimum value for trigger delay.To configure the instrument to use the shortest trigger delay, set thissetting to zero. The driver will coerce any value between zero and theminimum Trigger Delay value that you specify to the minimumsupported value. Trigger Delay is used only when the Trigger DelayMode setting is set to Use Specified Delay.

Supported values:

Auto Delay On (–1) Sets the DMM to calculate the trigger delaybefore each measurement.

Auto Delay Off (–2) Stops the DMM from calculating thetrigger delay and sets the trigger delay tothe last trigger delay the DMM calculated.

Use Specified Delay (0) Enables you to manually specify the lengthof time in seconds between the DMMreceiving the trigger and taking themeasurement.


Advanced TabThe following figure shows the Advanced tab for the Configure operation.

The Advanced tab for the Configure operation contains the followingcontrols:

• Sample Count—Specifies the number of measurements the DMMtakes each time it receives a trigger. The value of this setting affectsinstrument behavior only when the Multi Point extension is enabled.

• Sample Interval—Specifies the interval between samples in seconds.This setting affects instrument behavior only when Sample Count isgreater than 1, Sample Trigger is set to Interval ST, and the Multi Pointextension is enabled. If Sample Interval does not exactly match asupported value by an instrument driver, the instrument driver willcoerce up to the next supported value.

• Trigger Count—Specifies the number of triggers the DMM acceptsbefore it returns to the idle state. The value of this setting affectsinstrument behavior only when the Multi Point extension is enabled.

• Sample Trigger—Specifies the trigger source for each sample.The Sample Trigger setting is typically used when handshaking with aswitching system. For example, you can set up a switching system to


go through a scan specified by a switch scan list and set up the DMMto take a measurement at each channel specified in the scan list. Youcan connect the DMM's VMC (voltmeter complete) signal to triggerinput on the switching system. Also, the switching system can be setup so that once if finishes a step in its scan, it sends out a pulse on thescanner advanced line. That line can be hooked to the DMM's sampletrigger. If the value of the Sample Count is greater than 1, the DMMwaits until a sample trigger occurs after taking a single measurement.When the sample trigger specified by this setting occurs, the DMMtakes the next measurement. This setting affects instrument behavioronly when Sample Count is greater than 1 and the Multi Pointextension is enabled.

Supported values:

Immediate (1) Specifies that the DMM does not wait for atrigger before acquiring a sample.

External (2) Specifies that the DMM waits until asample trigger occurs on the externaltrigger input and then acquires a sample.

Software (3) Specifies that the DMM waits for a sampletrigger until the Send Software Triggeroperation executes and then acquires asample.

TTL0 (111) Specifies that the DMM waits until asample trigger occurs on TTL0 and thenacquires a sample.









ECL0 (119) Specifies that the DMM waits until asample trigger occurs on ECLO and thenacquires a sample.

ECL1 (120) Specifies that the DMM waits until asample trigger occurs on ECL1 and thenacquires a sample.

PXI STAR (131) Specifies that the DMM waits until asample trigger occurs on the PXI Startrigger bus and then acquires a sample.

RTSI0 (140) Specifies that the DMM waits until asample trigger occurs on RTSI0 and thenacquires a sample.







Interval (10) Specifies that the DMM waits for a sampletrigger to occur for the amount of timespecified by Sample Interval and thenacquires a sample.

• Meas Complete Dest—Specifies the destination of the measurementcomplete signal. After each measurement, the DMM generates ameasurement complete signal. This signal is sometimes referred to asVoltmeter Complete. The value of this setting affects instrumentbehavior only when the Multi Point extension is enabled.


Supported values:

None (–1) Does not route the measurement completesignal.

External (2) Routes the measurement complete signal tothe external connector.

TTL0 (111) Routes the measurement complete signal toTTL0.








ECL0 (119) Routes the measurement complete signal toECL0.

ECL1 (120) Routes the measurement complete signal toECL 1.

PXI STAR (131) Routes the measurement complete signal toPXI Star trigger bus.

RTSI0 (140) Routes the measurement complete signal toRTSI0.








• Voltage Range for Freq—Specifies the expected range of theamplitude of the input signal in volts RMS for frequency and periodmeasurements. If the Voltage Range For Freq setting does not exactlymatch a supported value by an instrument driver, the instrument driverwill coerce up to the next supported value. The value of this settingaffects instrument behavior only when the Frequency Measurementextension is enabled and the Measurement Function setting is set to afrequency or period measurement.

• Auto Zero Specifies the auto-zero mode. When the Auto Zero settingis enabled, the DMM internally disconnects the input signal and takesa zero reading. The DMM then subtracts the zero reading from themeasurement to prevent offset voltages present in the instrument’sinput circuitry from affecting measurement accuracy. The value of thissetting affects instrument behavior only when the Auto Zero extensionis enabled.

Supported values:

Auto Zero Off (0) Disables the auto-zero feature.

Auto Zero On (1) Configures the DMM to take a zero readingfor each measurement. The DMMsubtracts the zero reading from the value itmeasures.

Auto Zero Once (2) Configures the DMM to take a zero readingimmediately. The DMM then subtracts thiszero reading from all subsequent values itmeasures.

• Powerline Freq—Specifies the power line frequency in Hertz. Somedevices require that the frequency of the power line that they areconnected is specified for accurate measurements. The value of thissetting affects instrument behavior only when the PowerlineFrequency extension is enabled.

• Trigger Slope—Specifies the polarity of the external trigger slope.The DMM triggers on either the rising or the falling edge of theexternal trigger source depending on the value of the Trigger Slopesetting. The value of this setting affects instrument behavior only whenthe Trigger Slope extension is enabled.

Supported values:

Positive (0) Sets the trigger event to occur on the risingedge of the trigger pulse.

Negative (1) Sets the trigger event to occur on the fallingedge of the trigger pulse.


Temperature TabThe following figure shows the Temperature tab for the Configureoperation.

The Temperature tab for the Configure operation contains the followingcontrols:

• Transducer Type—Specifies the device used to measure thetemperature. The value of this setting affects instrument behavior onlywhen the Temperature Measurement extension is enabled and theMeasurement Function setting is set to Temp.

Supported values:

Thermocouple (1) Sets the DMM to measure temperatureusing a thermocouple.

Thermistor (2) Sets the DMM to measure temperatureusing a thermistor.


2 Wire RTD (3) Sets the DMM to measure temperatureusing a 2-wire temperature resistancedevice.

4 Wire RTD (4) Sets the DMM to measure temperatureusing a 4-wire temperature resistancedevice.

• Thermistor Resistance—Specifies the resistance of the thermistor inohms. The value of this setting affects instrument behavior only whenthe Thermistor and Temperature Measurement extensions are enabledand the Transducer Type is set to Thermistor.

• Rtd Alpha—Specifies the alpha parameter for a resistancetemperature device (RTD). The value of this setting affects instrumentbehavior only when the RTD and Temperature Measurementextensions are enabled and the Transducer Type is set to 2 Wire RTDor 4 Wire RTD.

• Rtd Resistance—Specifies the R0 parameter (resistance) for aresistance temperature device (RTD) in ohms. The RTD resistance isalso known as the RTD reference value. The value of this settingaffects instrument behavior only when the RTD and TemperatureMeasurement extensions are enabled and the Transducer Type is set to2 Wire RTD or 4 Wire RTD.

• Thermocouple Type—Specifies the type of thermocouple used tomeasure the temperature. The value of this setting affects instrumentbehavior only when the Thermocouple and Temperature Measurementextensions are enabled and the Transducer Type is set toThermocouple.

B (1) Measures temperature from a B-typethermocouple.

C (2) Measures temperature from a C-typethermocouple.

D (3) Measures temperature from a D-typethermocouple.

E (4) Measures temperature from a E-typethermocouple.

G (5) Measures temperature from a G-typethermocouple.

J (6) Measures temperature from a J-typethermocouple.

K (7) Measures temperature from a K-typethermocouple.

N (8) Measures temperature from a N-typethermocouple.


R (9) Measures temperature from a R-typethermocouple.

S (10) Measures temperature from a S-typethermocouple.

T (11) Measures temperature from a T-typethermocouple.

U (12) Measures temperature from a U-typethermocouple.

V (13) Measures temperature from a V-typethermocouple.

• Reference Junction Type—Specifies the type of reference junction tobe used in the reference junction compensation of a thermocouplemeasurement.

Supported values:

Internal (1) Sets the DMM to use an internal sensor atthe thermocouple junction for the junctioncompensation.

Fixed (2) Sets the DMM to use a fixed value for thethermocouple junction compensation.


Extensions TabThe following figure shows the Extensions tab for the Configure operation.

The Extensions tab for the Configure operation contains the followingcontrols.

• AC Measurement—Supports the IviDmmACMeasurement extensiongroup.

• Frequency Measurement—Supports theIviDmmFrequencyMeasurement extension group.

• Temperature Measurement—Supports theIviDmmTemperatureMeasurement extension group.

• Multi Point—Supports the IviDmmMultiPoint extension group.

• Trigger Slope—Supports the IviDmmTriggerSlope extension group.

• Software Trigger—Supports the IviDmmSoftwareTrigger extensiongroup.

• Device Info—Supports the IviDmmDeviceInfo extension group.

• Auto Range Value—Supports the IviDmmAutoRangeValueextension group.


• Auto Zero—Supports the IviDmmAutoZero extension group.

• Powerline Frequency—Supports the IviDmmPowerLineFrequencyextension group.

Operation Settings TabThe Operations Settings tab specifies to which property or variable the stepsaves the operation settings to when closing the edit dialog, and reloads theoperation settings when displaying the edit dialog.

Read and FetchThe Read operation initiates and returns a measurement from aninstrument. Read is a higher-level acquisition operation that encapsulatessome of the details of using the Initiate and Fetch operations. If SampleCount setting is greater than 1 and the Multi Point extension is enabled, theRead operation returns an array of values. Otherwise the operation returnsa single value.

The returned value is either the actual reading in units defined by theMeasurement Function setting, or a value indicating that an overrangecondition occurred.

If an overrange condition occurs, the reading parameter contains anIEEE-defined NaN (not a number) value. To test a value for the overrangecondition, specify a status expression in the Set Status if Over-Rangecontrol. If Timeout seconds occur before the Read operation completes, theSet Status on Timeout control determines the step status.

The Fetch operation returns the measured value from a measurement thatthe Initiate operation started. If Trigger Count is greater than 1 and theMulti Point extension is enabled, the Fetch operation returns an array ofvalues. Otherwise it returns a single value. Typically, this operation is calledonly in a sequence of calls to other low-level driver operations, such as theInitiate operation. Before issuing a Fetch operation, use the Initiateoperation in a separate step to initiate a measurement. If you perform otheroperations on the instrument after the call to an Initiate operation but priorto issuing a Fetch operation, the Fetch operation might not return valid data.


The following figure shows the Read operation.

The Read operation contains the following controls:

• Data Type—Specifies whether the step expects a single value or arrayof values. The step coerces the data type of the Step.Result.Readingproperty to NI_IviSinglePoint or NI_IviWave, respectively.

• Measurement Destination—Specifies a variable or property to whichthe step assigns the measurement value. For single values, the data typeof the variable or property must be Number or NI_IviSinglePoint. Forarray of values, the data type of the variable or property must be arrayof Number or NI_IviWave. The default configuration for the stepspecifies Step.Result.Reading as the destination. When you edit thestep, the step automatically coerces the data type of theStep.Result.Reading property to NI_IviSinglePoint or NI_IviWave,based on the value of the Data Type control. If you do not specifyStep.Result.Reading as the destination, TestStand still copies themeasurement value to the Step.Result.Reading.Data property atruntime unless the Copy Data to Execution Results is unchecked.

• Timeout—Specifies the timeout in milliseconds for the operation. TheTimeout setting applies to the length of time between initializing a callto Read and completing the data acquisition, not the time required by


the DMM for computations or to transfer data across theinstrumentation bus. To set an infinite timeout, set the Timeout settingto –1.

• Set Status on Timeout—Specifies the status for the step result if atimeout condition occurs. If you leave this control blank, the stepignores timeout conditions.

• Set Status on Over-Range—Specifies the status for the step result ifa timeout condition occurs. If you leave this control blank, the stepdoes not check for an overrange condition.

• Copy Data To Execution Results—Specifies whether the TestStandcopies the measurement value stored in the propertyStep.Result.Reading.Data to the step result. If you enable this control,TestStand cannot include the measurement in a report or log themeasurement to database. For single-point measurements, this settingis always checked.

InitiateThe Initiate operation initiates a measurement. When this operationexecutes, the DMM leaves the idle state and waits for a trigger. Use theFetch operation to retrieve the measurement that was started by the Initiateoperation. This operation does not check the instrument status. Typically,this operation is called only in a sequence of calls to other low-level driveroperations, such as the Fetch operation.

AbortThe Abort operation aborts a previously initiated measurement and returnsthe instrument to the idle state. This operation does not check theinstrument status. Typically, this operation is called only in a sequence ofcalls to other low-level driver operations, such as the Initiate operation.

Send SW TriggerThe Send SW Trigger operation sends a software trigger command totrigger the instrument. This operation affects the behavior of the instrumentif the Trigger Source setting is set to Software Trig and the SoftwareTrigger extension is enabled. This operation does not check the instrumentstatus. Typically, this operation is called only in a sequence of calls to otherlow-level driver operations, such as the Initiate operation.

Get InformationThe Get Information operation retrieves low-level status and informationfrom the instrument.


The following figure shows the Get Information operation.

The Get Information operation contains the following controls:

• Get Auto Range Value—Specifies a variable or property to which thestep assigns the range value when the DMM is autoranging. When theRange Mode setting is set to Auto Range On, the Range setting doesnot accurately reflect the current range. If you are autoranging theDMM, use this control to retrieve the range that the instrument has setitself to.

• Get Aperture Time Info—Returns information about the aperturetime. This operation works only on instrument drivers that support theDevice Info Ext extension.

– Time—Specifies a variable or property to which the step assignsthe aperture time, also known as the integration time. Units ofaperture time are returned by the Units control.

– Units—Specifies a variable or property to which the step assignsthe units of aperture time. A value of 1 specifies the aperture timeis in powerline cycles. A value of 0, specifies the aperture time isin seconds.


Step PropertiesFigure 4 shows the step properties for the IVI Dmm step type.

Figure 4. IVI Dmm Step Properties


The IVI Dmm step type defines the following step properties in addition tothe common custom properties:

• Step.Result.Reading contains the measurement values for the Readand Fetch operations. The property data type is eitherNI_IviSinglePoint or NI_IviWave.

• Step.Logical.Name contains the logical name expression.

• Step.InstrOperation contains a value that specifies the operation thestep is set to perform.

• Step.SettingSource contains the name of the property or variablewhere the step loads and stores the settings for the operation.

• Step.Configuration contains the settings for the Configure operation.The data type of this property is NI_IviDmmConfig.

• Step.SoftFrontPanel contains the settings for the Show Soft FrontPanel operation. The data type of this property isNI_IviSoftFrontPanel.

• Step.Readings contains the settings for the Read and Fetch operations.

• Step.GetInfo contains the settings for the Get Information operation.

IVI Scope StepYou use the IVI Scope step type to acquire a voltage waveform from ananalog input signal with oscilloscopes. The step type supports thefollowing operations.




• Read—Initiates and returns a measurement from an instrument.

• Initiate—Initiates a measurement.

• Fetch—Returns the measured value from a measurement that theInitiate operation has started.


• Auto Setup—Performs an automatic setup on the instrument.






• Measurement Function—Specifies how the oscilloscope acquiresdata and fills the waveform record.

Supported values:

Normal (0) Configures the oscilloscope to acquire onesample for each point in the waveformrecord. The oscilloscope uses real-time orequivalent time sampling.

Peak Detect (1) Sets the oscilloscope to the peak-detectacquisition mode. The oscilloscopeoversamples the input signal and keeps theminimum and maximum values that


correspond to each position in thewaveform record. The oscilloscope usesonly real-time sampling.

Hi Res (2) Configures the oscilloscope to oversamplethe input signal. The oscilloscopecalculates the average value thatcorresponds to each position in thewaveform record. The oscilloscope usesonly real-time sampling.

Envelope (3) Sets the oscilloscope to the envelopeacquisition mode. The oscilloscopeacquires multiple waveforms and keeps theminimum and maximum voltages itacquires for each point in the waveformrecord. Specify the number of waveformsthe oscilloscope acquires with the NumEnvelopes setting. The oscilloscope canuse real-time or equivalent-time sampling.

Average (4) Configures the oscilloscope to acquiremultiple waveforms and calculate theaverage value for each point in thewaveform record. Specify the number ofwaveforms to acquire with the NumAverages setting. The oscilloscope usesreal-time or equivalent time sampling.

• Interpolation—Specifies the interpolation method the oscilloscopeuses when it cannot resolve a voltage for every point in the waveformrecord. The value of this setting affects instrument behavior only whenthe interpolation extension is enabled.

Support values:

No Interpolation (1) Specifies that the oscilloscope does notinterpolate points in the waveform. Instead,the driver sets every element in thewaveform record for which theoscilloscope cannot receive a value to anIEEE-defined NaN (not a number) value.

Sine X (2) Specifies that the oscilloscope uses asin(x)/x calculation to interpolate a valuewhen it cannot resolve a voltage in thewaveform record.

Linear (3) Specifies that the oscilloscope uses a linearapproximation to interpolate a value whenit cannot resolve a voltage in the waveformrecord.


• Num Averages—Specifies the number of waveforms the oscilloscopeacquires and averages. After the oscilloscope acquires as manywaveforms as this setting specifies, it returns to the idle state. Thevalue of this setting affects instrument behavior only when the AverageAcquisition extension is enabled and the Acquisition Type is set toAverage.

• Num Envelopes—Specifies the number of waveforms theoscilloscope acquires and analyzes to create the minimum andmaximum waveforms. When you set the Acquisition Type setting toEnvelope, the oscilloscope acquires multiple waveforms. After eachwaveform acquisition, the oscilloscope keeps the minimum andmaximum values it finds for each point in the waveform record. TheNum Envelopes setting specifies the number of waveforms theoscilloscope acquires and analyzes to create the minimum andmaximum waveforms. After the oscilloscope acquires as manywaveforms as this setting specifies, it returns to the idle state. Thevalue of this setting affects instrument behavior only when you enablethe Min Max Waveform extension and set the Acquisition Type settingto Envelope.

• Horizontal Min Num Points—Specifies the minimum number ofpoints the end user requires in the waveform record for each channel.The instrument driver uses the value that you specify to configure therecord length that the oscilloscope uses for waveform acquisition. Ifthe instrument cannot support the requested record length, the drivermust configure the instrument to the closest supported record length.The value of the supported record length will be larger than therequested length. Use the Get Actual Record Length operation to getthe actual record length for the acquisition.

• Horizontal Time Per Record—Specifies the length of time inseconds that corresponds to the record length. If Time Per Record doesnot exactly match a supported value by an instrument driver, theinstrument driver will coerce up to the next supported value.

• Horizontal Acq Start Time—Specifies the length of time in secondsfrom the trigger event to the first point in the waveform record. If theAcquisition Start Time value is positive, the first point in the waveformrecord occurs after the trigger event. If the value is negative, the firstpoint in the waveform record occurs before the trigger event.


Advanced TabThe following figure shows the Advanced tab for the Configure operation.

The Advanced tab for the Configure operation contains the followingcontrols:

• Low Reference—Specifies the low reference that the oscilloscopeuses for waveform measurements. The value is a percentage of thedifference between Voltage High and Voltage Low. The value of thissetting affects instrument behavior only when the WaveformMeasurement extension is enabled.

• Middle Reference—Specifies the middle reference in percentage thatthe oscilloscope uses for waveform measurements. The value is apercentage of the difference between Voltage High and Voltage Low.The value of this setting affects instrument behavior only when theWaveform Measurement extension is enabled.

• High Reference—Specifies the high reference that the oscilloscopeuses for waveform measurements. The value is a percentage of thedifference between Voltage High and Voltage Low. The value of thissetting affects instrument behavior only when the WaveformMeasurement extension is enabled.


Channels TabThe following figure shows the Channels tab for the Configure operation.

The Channels tab contains a list control with the default channels for theselected logical name. You can use the Add and Remove buttons to add newchannels and remove existing channels from the list. You can specifywhether the oscilloscope acquires a waveform for the channel by enablingthe channel using the check box within the list control. If you enable thePreserve Existing Channels checkbox, the step adds to or modifies anyexisting channels previously configured. When you uncheck the PreserveExisting Channels check box, the step deletes all previously configuredchannels before configuring the specified channels in the list.

The Channels tab for the Configure operation contains the followingchannel specific controls:

• Name—Specifies the name of the channel. The channel name must bea valid virtual channel name as defined by the IVI configuration for thelogical name being used.

• Vertical Coupling—Specifies how the oscilloscope couples the inputsignal for the channel.


Supported values:

AC (0) Specifies that the oscilloscope AC couplesthe input signal.

DC (1) Specifies that the oscilloscope DC couplesthe input signal.

Gnd (2) Specifies that the oscilloscope couples thechannel to the ground.

• Vertical Range—Specifies the absolute value of the input range involts for a channel. For example, to acquire a sine wave that spansbetween –5.0 and 5.0 volts, set the value to 10.0 volts. If Vertical Rangedoes not exactly match a supported value by an instrument driver, theinstrument driver will coerce up to the next supported value.

• Vertical Offset—Specifies the center of the range in volts specified bythe Vertical Range setting. This setting value is set with respect toground in volts. For example, to acquire a sine wave that spansbetween 0.0 and 10.0 volts, set vertical offset to 5.0 volts.

• Max Input Freq—Specifies the maximum frequency for the inputsignal you want the instrument to accommodate without attenuating itby more than 3dB. If the bandwidth limit frequency of the instrumentis greater than this maximum frequency, the driver enables thebandwidth limit to attenuate the input signal by at least 3dB atfrequencies greater than the bandwidth limit. If Max Input Frequencydoes not exactly match a supported value by an instrument driver, theinstrument driver will coerce up to the next supported value.

• Probe Attenuation—Specifies the scaling factor that the probeattached to the channel uses to attenuate the input. If the value is –1,the oscilloscope is configured to use automatic probe sensing. If thevalue is positive, the oscilloscope is configured to use the specifiedmanual probe attenuation. For example, for a 10:1 probe, set thissetting to 10.0. If you are using automatic probe sensing, use the GetAuto Probe Sense Value operation to determine the actual probe.

• Input Impedance—Specifies the input impedance for the channel inohms. Common values are 50.0, 75.0, and 1,000,000.0.


Trigger TabThe following figure shows the Trigger tab for the Configure operation.

The Trigger tab for the Configure operation contains the followingcontrols:

• Type—Specifies the event that triggers the oscilloscope.

Supported values:

AC Line (7) Configures the oscilloscope for AC Linetriggering.

Edge (1) Configures the oscilloscope for edgetriggering. An edge trigger occurs when thetrigger signal specified with the TriggerSource setting passes the voltage thresholdspecified with the Trigger Level setting andhas the slope specified with the TriggerSlope setting.

Glitch (4) Configures the oscilloscope for glitchtriggering.


Immediate (6) Configures the oscilloscope for immediatetriggering. The oscilloscope does not waitfor a trigger of any kind upon initialization.

Runt (3) Configures the oscilloscope for runttriggering.

TV (5) Configures the oscilloscope for triggeringon TV signals.

Width (2) Configures the oscilloscope for widthtriggering.

• Source—Specifies the source that the oscilloscope monitors for thetrigger event. Source is a string that can be a defined virtual channelname, an instrument specific channel string, or one of the followingdefined values:

“IVISCOPE_VAL_EXTERNAL”

“IVISCOPE_VAL_GPIB_GET”

“IVISCOPE_VAL_TTL0”








“IVISCOPE_VAL_ECL0”

“IVISCOPE_VAL_ECL1”

“IVISCOPE_VAL_PXI_STAR”

“IVISCOPE_VAL_RTSI_0”







• Holdoff—Specifies the length of time in seconds the oscilloscopewaits after it detects a trigger until the oscilloscope enables the triggersubsystem to detect another trigger. The Holdoff setting affectsinstrument operation only when the oscilloscope requires multipleacquisitions to build a complete waveform. The oscilloscope requiresmultiple waveform acquisitions when it uses equivalent time samplingor when the Acquisition Type is set to Envelope or Average. Many


scopes have a small, nonzero value as the minimum value for thissetting. To configure the instrument to use the shortest trigger holdoff,specify a value of zero. The instrument driver will coerce any valuebetween zero and the minimum value you specify to the minimumsupported value.

• Coupling—Specifies how the oscilloscope couples the trigger source.

Supported values:

AC (0) Specifies that the oscilloscope AC couplesthe trigger signal.

DC (1) Specifies that the oscilloscope DC couplesthe trigger signal.

HF Reject (3) Specifies that the oscilloscope filters outthe high frequencies from the triggersignal.

LF Reject (4) Specifies that the oscilloscope filters outthe low frequencies from the trigger signal.

Noise Reject (5) Specifies that the oscilloscope filters outthe noise from the trigger signal.

• Modifier—Determines the oscilloscope's behavior in the absence ofthe configured trigger. The value of this setting affects instrumentbehavior only when the Trigger Modifier extension is enabled.

Supported values:

Auto (2) Specifies that the oscilloscopeautomatically triggers if the configuredtrigger does not occur within the timeoutperiod.

Auto Level (3) Specifies that the oscilloscope adjusts thetrigger level if the trigger you specify doesnot occur.

No Trigger Mod (1) Specifies that the oscilloscope wait untilthe specified trigger occurs.

• Initiate Continuous—Continuously initiates waveform acquisitionwhen set to True. The value of this setting affects instrument behavioronly when the Continuous Acquisition extension is enabled. Thissetting does not affect the behavior of the Read and Fetch operationsbecause these operations are instrument specific. Set this setting toTrue when you need continuous updates of the oscilloscope display.

• Level—Specifies a level setting for the following trigger types.

– Edge—Specifies the threshold in volts for the trigger subsystem.The value of this setting affects instrument behavior only when theTrigger Type is Edge.


– Glitch—Specifies the threshold in volts for the trigger subsystem.The value of this setting affects instrument behavior only when theGlitch Trigger extension is enabled and the Trigger Type setting isset to Glitch.

– Width—Specifies the level in volts at which the pulse causes atrigger. The value of this setting affects instrument behavior onlywhen the Width Trigger extension is enabled and the Trigger Typesetting is set to Width.

• Condition—Specifies the condition for the following trigger types.

– Glitch—Specifies the range in which the glitch trigger occurs.This setting determines if the glitch trigger happens when theoscilloscope detects a pulse with a width less than or greater thanthe width value. The value of this setting affects instrumentbehavior only when the Glitch Trigger extension is enabled andthe Trigger Type setting is set to Glitch.

Supported values:

Greater Than (2) Triggers the oscilloscope when the pulsewidth is greater than the value you specifywith the Glitch Width setting.

Less Than (1) Triggers the oscilloscope when the pulsewidth is less than the value you specifywith the Glitch Width setting.

– Width—Specifies if a pulse that is inside or outside the high andlow thresholds triggers the oscilloscope. The value of this settingaffects instrument behavior only when the Width Triggerextension is enabled and the Trigger Type setting is set to Width.

Supported values:

Width Outside (2) Configures the oscilloscope to trigger onpulses that have a width that is eithergreater than the high threshold or less thana low threshold. You can specify the highand low thresholds with the HighThreshold and Low Threshold settings.

Width Within (1) Configures the oscilloscope to trigger onpulses that have a width that is less than thehigh threshold and greater than the lowthreshold. You can specify the high and lowthresholds with the High Threshold andLow Threshold settings.


• Event—Specifies the event on which the oscilloscope triggers. Thevalue of this setting affects instrument behavior only when the TVTrigger extension is enabled and the Trigger Type setting is set to TV.

Supported Values:

Any Field (3) Sets the oscilloscope to trigger on any field.

Any Line (4) Sets the oscilloscope to trigger on any line.

Field1 (1) Sets the oscilloscope to trigger on field 1 ofthe video signal.

Field2 (2) Sets the oscilloscope to trigger on field 2 ofthe video signal.

Line Number (5) Sets the oscilloscope to trigger on any line.

• Line Number—Specifies the line on which the oscilloscope triggers.The line number setting is independent of the field. To trigger on thefirst line of the second field, you must configure the line number to thevalue of 263 (if you presume that the first field has 262 lines). Thevalue of this setting affects instrument behavior only when the TVTrigger extension is enabled, the Trigger Type setting is set to TV, andthe TV Event setting is set to TV Line Number.

• Signal Format—Specifies the format of TV signal on which theoscilloscope triggers. The value of this setting affects instrumentbehavior only when the TV Trigger extension is enabled and theTrigger Type setting is set to TV.

Supported values:

NTSC (1) Configures the oscilloscope to trigger onthe NTSC signal format.

PAL (2) Configures the oscilloscope to trigger onthe PAL signal format.

SECAM (3) Configures the oscilloscope to trigger onthe SECAM signal format.

• Polarity—Specifies a polarity setting for the following trigger types.

– Glitch—Specifies the polarity of the glitch. The value of thissetting affects instrument behavior only when the Glitch Triggerextension is enabled and the Trigger Type setting is set to Glitch.

Supported values:

Positive (1) Triggers the oscilloscope on a positiveglitch.

Negative (2) Triggers the oscilloscope on a negativeglitch.

Either (3) Triggers the oscilloscope on either apositive or negative glitch.


– Runt—Specifies the polarity of the runt that triggers theoscilloscope. The value of this setting affects instrument behavioronly when the Runt Trigger extension is enabled and the TriggerType setting is set to Runt.

Supported values:

Positive (1) Triggers the oscilloscope on a positive runt.A positive runt occurs when a rising edgecrosses the low runt threshold and does notcross the high runt threshold beforerecrossing the low runt threshold.

Negative (2) Triggers the oscilloscope on a negativerunt. A negative runt occurs when a fallingedge crosses the high runt threshold anddoes not cross the low runt threshold beforerecrossing the high runt threshold.

Either (3) Triggers the oscilloscope on either apositive or negative runt.

– TV—Specifies the polarity of the TV signal. The value of thissetting affects instrument behavior only when the TV Triggerextension is enabled and the Trigger Type setting is set to TV.

Supported values:

Negative (0) Configures the oscilloscope to trigger on anegative video sync pulse.

Positive (1) Configures the oscilloscope to trigger on apositive video sync pulse.

– Width—Specifies the polarity of the pulse that triggers theoscilloscope. The value of this setting affects instrument behavioronly when the Width Trigger extension is enabled and TriggerType is Width.

Supported values:

Negative (2) Configures the oscilloscope to trigger onnegative pulses that have a width that meetsthe condition specified with the Conditionsetting.

Positive (1) Configures the oscilloscope to trigger onpositive pulses that have a width that meetsthe condition specified with the Conditionsetting.


• Slope—Specifies a slope setting for the following trigger type.

– AC Line—Specifies the slope of the zero crossing upon which thescope triggers. The value of this setting affects instrumentbehavior only when the AC Line Trigger extension is enabled andthe Trigger Type setting is set to AC Line.

Supported values:

Positive (1) Configures the oscilloscope to trigger onpositive slope zero crossings of thenetwork supply voltage.

Negative (2) Configures the oscilloscope to trigger onnegative slope zero crossings of thenetwork supply voltage.

Either (3) Configures the oscilloscope to trigger oneither positive or negative slope zerocrossings of the network supply voltage.

– Edge—Specifies whether a rising or falling edge triggers theoscilloscope. The value of this setting affects instrument behavioronly when the Trigger Type is Edge.

Support values:

Negative (0) Specifies that a negative (falling) edgepassing through the trigger level triggersthe oscilloscope.

Positive (1) Specifies that a positive (rising) edgepassing through the trigger level triggersthe oscilloscope.

• Width—Specifies the width setting for the following trigger types.

– Glitch—Specifies the glitch width in seconds. The oscilloscopetriggers when it detects a pulse with a width less than or greaterthan this value, depending on the value of the Glitch Conditionsetting. The value of this setting affects instrument behavior onlywhen the Glitch Trigger extension is enabled and the Trigger Typesetting is set to Glitch.

• High Threshold—Specifies the high threshold for the followingtrigger types.

– Runt—Specifies the high threshold in volts that the oscilloscopeuses for runt triggering. The value of this setting affectsinstrument behavior only when the Runt Trigger extension isenabled and the Trigger Type setting is set to Runt.

– Width—Specifies the high width threshold time in seconds. Forthe instrument to trigger, the pulse length must be between theHigh Threshold and Low Threshold values. The value of this


setting affects instrument behavior only when the Width Triggerextension is enabled and the Trigger Type setting is set to Width.

• Low Threshold—Specifies the high threshold for the followingtrigger types.

– Runt—Specifies the low threshold in volts that the oscilloscopeuses for runt triggering. The value of this setting affectsinstrument behavior only when the Runt Trigger extension isenabled and the Trigger Type setting is set to Runt.

– Width—Specifies the low width threshold time in seconds. Forthe instrument to trigger, the pulse length must be between theHigh Threshold and Low Threshold values. The value of thissetting affects instrument behavior only when the Width Triggerextension is enabled and the Trigger Type setting is set to Width.



The Extensions tab for the Configure operation contains the followingcontrols:

• TV Trigger—Supports extensions for oscilloscopes capable oftriggering on TV signals.

• Runt Trigger—Supports extensions for oscilloscopes with thecapability to trigger on runt pulses. A runt condition occurs when theoscilloscope detects a positive or negative going pulse that crosses onevoltage threshold but fails to cross a second threshold beforerecrossing the first. You can select whether a positive runt, negativerunt, or either runt type triggers the acquisition.

• Glitch Trigger—Supports extensions for oscilloscopes that cantrigger on a glitch pulses. A glitch occurs when the oscilloscopedetects a pulse width that is less than or a greater than a specified glitchduration. You can select whether a positive glitch, negative glitch, oreither glitches trigger the acquisition.

• Width Trigger—Supports extensions for oscilloscopes capable oftriggering on user-specified pulse widths. Width triggering occurswhen the oscilloscope detects a positive or negative pulse with a widthbetween, or optionally outside, the user-specified threshold.

• AC Line Trigger—Supports extensions for oscilloscopes that arecapable of synchronizing the trigger with the AC Line. AC Linetriggering occurs when the oscilloscope detects a positive zerocrossing, negative zero crossing, or optionally either positive ornegative zero crossing on the network supply voltage.

• Trigger Modifier—Supports extensions for oscilloscopes that canspecify the behavior of the triggering subsystem in the absence of theconfigured trigger.

• Waveform Measurement—Supports extensions for oscilloscopescapable of calculating various measurements, such as rise-time,fall-time, period, and frequency, from an acquired waveform.

• Min Max Waveform—Supports extensions for oscilloscopes that canacquire minimum and maximum waveforms that correspond to thesame range of time. The two most common acquisition types in whichoscilloscopes return minimum and maximum waveforms are envelopeand peak detect.

• Average Acquisition—Supports extensions for oscilloscopes that canperform the average acquisition.

• Interpolation—Supports extensions for oscilloscopes capable ofinterpolating values in the waveform record that the oscilloscope'sacquisition subsystem was unable to digitize.

• Probe Auto Sense—Supports extensions for oscilloscopes that canreturn the probe attenuation of the attached probe.


• Sample Mode—Supports extensions for oscilloscopes that can returnwhether the scope is using equivalent time or real time sampling toacquire waveform.

• Auto Setup—Supports extensions for oscilloscopes that can performan auto setup operation.

• Continuous Acquisition—Supports extensions for oscilloscopes thatcan perform a continuous acquisition.


Read and FetchThe Read operation initiates an acquisition and retrieves the measuredvalue(s) from a previously started acquisition for the listed channels. Readinitiates a new measurement on all channels. You can obtain data frommultiple channels or different types of data from a single channel based onsingle trigger condition.

The returned value is either the actual reading (in units defined by theWaveform Type, or a value indicating that an overrange condition occurred.If an overrange condition occurs, the reading parameter contains anIEEE-defined NaN (not a number) value. To test a value for the overrangecondition, enable the Set Status if Over-Range control. If Timeout secondsoccur before the Read operation completes, the Set Status on Timeoutcontrol determines the step status.

The Fetch operation retrieves the measured value(s) from a previouslystarted acquisition for the listed channels. Before calling Fetch, use theInitiate operation or use the Read operation on any channel to initiate ameasurement. You can use the Fetch operation multiple times on a channelto retrieve different types of data from the same acquisition. This operationdoes not check the instrument status. Typically, the Fetch operation iscalled only in a sequence of calls to other low-level driver operations, suchas the Initiate operation.


Channels TabThe following figure shows the Read operation.

The Channels tab contains a list control with the default channels for theselected logical name. You can use the Add and Remove buttons to add newchannels and remove existing channels from the list. You can specifywhether the oscilloscope acquires a waveform for the channel by enablingthe channel using the check box within the list control.

The Channels tab for the Read operation contains the following channelspecific controls:

• Name—Specifies the name of the channel to read. The channel namemust be a valid virtual channel name as defined by the IVIconfiguration for the logical name being used.

• Waveform Type—Specifies the type of data to retrieve from theoscilloscope. Depending on this value, the returned data is a singlevalue (for a measurement), a one-dimensional array (Waveform), or atwo-dimensional array (Waveform Min Max).

Supported values:

Amplitude (15) High Voltage less the Low Voltage in voltsover the entire waveform.


Negative Duty Cycle (13)Ratio of the Negative Width to the Periodof an integer number of cycles in thewaveform expressed as a percentage.

Positive Duty Cycle (14) Ratio of the Positive Width to the Period ofan integer number of cycles in thewaveform expressed as a percentage.

Fall Time (1) Length of time in seconds for a falling edgeof the signal to fall from the high referencelevel to the low reference level.

Frequency (2) Frequency in hertz of one complete cycle inthe waveform.

Overshoot (18) Relative waveform distortion that followsan edge transition.

Period (3) Length of time in seconds of one completecycle in the waveform.

Preshoot (19) Relative waveform distortion that precedesan edge transition.

Rise Time (0) Length of time in seconds for a rising edgeof the signal to rise from the low referencelevel to the high reference level.

Average Voltage (10) Arithmetic average in volts measured overthe entire waveform.

Cycle Average Voltage (17)Arithmetic average in volts over an integernumber of cycles in the waveform.

Cycle Rms Voltage (16) True Root Mean Square (RMS) voltageover an integer number of cycles in thewaveform.

High Voltage (8) Voltage that corresponds to 100% whenusing the reference levels. The oscilloscopecalculates this value using either themin/max or histogram methods. Themin/max method uses the maximum valuefound. The histogram method uses acommon value found above the middle ofthe waveform.

Low Voltage (9) Voltage that corresponds to 0% when usingthe reference levels. The oscilloscopecalculates this value using either themin/max or histogram methods. Themin/max method uses the minimum valuefound. The histogram method uses a


common value found below the middle ofthe waveform. The units are volts.

Max Voltage (6) Maximum amplitude in volts found in theentire waveform.

Min Voltage (7) Minimum amplitude in volts found in theentire waveform.

Peak To Peak Voltage (5)Absolute difference in volts between theMax Voltage and the Min Voltage.

Rms Voltage (4) True Root Mean Square (RMS) voltage ofthe entire waveform.

Negative Width (11) Length of time in seconds between themid-reference level points of a negativepulse in the waveform.

Positive Width (12) Length of time in seconds between themid-reference level points of a positivepulse in the waveform.

Waveform (–1) Specifies that the Read/Fetch operationacquires a waveform with the currentconfiguration. If specified, Read returns aone-dimensional array of points.

Min/Max (–2) Specifies that the Read/Fetch operationacquires a min-max waveform(two-dimensional array). This constant isvalid only if Acquisition Type is set to PeakDetect or Envelope.

• Data Type—Specifies whether the step expects a single value, arrayof values, or wave pair. The step coerces the data type of the elementsin the array property, Step.Result.Reading, to NI_IviSinglePoint,NI_IviWave, or NI_IviWavePair respectively.

• Measurement Destination—Specifies a variable or property to whichthe step assigns the measurement value. For single values, the data typeof the variable or property must be Number or NI_IviSinglePoint. Forarray of values, the data type of the variable or property must be arrayof Number or NI_IviWave. For a wave pair, the data type of thevariable or property must be 2D array of Number or NI_IviWavePair.The default configuration for the step specifies Step.Result.Reading asthe destination. This property is an array of container, and the size ofthe array is equal to the number of channels specified for the Read orFetch operation. When you edit the step, the step automatically resizedthe array and coerces the data type of each element of the array toNI_IviSinglePoint, NI_IviWave or NI_IviWavePair, based on the valueof the Data Type control for each channel. If you do not specifyStep.Result.Reading as the destination, TestStand still copies the


measurement value to the Data subproperty in each array element atruntime unless the Copy Data to Execution Results is unchecked.

• Set Status on Over-Range—Specifies the status for the step result ifa timeout condition occurs. If you leave this control blank, the stepdoes not check for an overrange condition.

• Copy Data To Execution Results—Specifies whether the TestStandcopies the measurement value stored in the propertyStep.Result.Reading.Data to the step result. If you enable this control,TestStand cannot include the measurement in a report or log themeasurement to database. For single-point measurements, this settingis always checked.

The Timeout control specifies the timeout in milliseconds for the operation.The Timeout setting applies to the length of time between initializing a callto Read and completing the data acquisition, not the time required by theinstrument for computations or to transfer data across the instrumentationbus. To set an infinite timeout, set the Timeout setting to –1.

The Set Status on Timeout control specifies the status for the step result ifa timeout condition occurs. If you leave this control blank, the step ignorestimeout conditions.


InitiateThe Initiate operation initiates an acquisition. After calling this operation,the oscilloscope leaves the idle state and waits for a trigger. Theoscilloscope acquires a waveform for each enabled channel. This operationdoes not check the instrument status. Typically, this operation is called onlyin a sequence of calls to other low-level driver operations, such as the Fetchoperation.

AbortThe Abort operation aborts a previously initiated measurement and returnsthe instrument to the idle state. This operation does not check theinstrument status. Typically, this operation is called only in a sequence ofcalls to other low-level driver operations, such as the Initiate operation.


Auto SetupThe Auto Setup operation performs an automatic setup on the instrument.Performing an automatic setup causes the instrument to put itself into aknown state. Since the auto setup operation is different on each instrument,using Auto Setup will break interchangeability. Auto Setup is onlyrecommended for cases where further calls to the instrument are notplanned.




• Get Actual Record Length—Specifies a variable or property towhich the step assigns the actual number of points the oscilloscopeacquires for each channel. After calling Configure you can call the GetActual Record Length operation to determine the size of the


waveforms that the oscilloscope acquires with the Read or Fetchoperations. The value is equal to or greater than the minimum numberof points specified by the Min Record Length setting. The oscilloscopemight use records of varying sizes depending on the acquisition type.

• Get Sample Rate—Specifies a variable or property to which the stepassigns the effective sample rate of the acquired waveform using thecurrent configuration in samples per second.

• Get Sample Mode—Specifies a variable or property to which the stepassigns the oscilloscope's current sampling mode.

Supported values:

Equivalent Time (1) Specifies that the oscilloscope usesequivalent time sampling.

Real Time (0) Specifies that the oscilloscope usesreal-time sampling.

• Get Acquisition Status—Specifies a variable or property to which thestep assigns a value that indicates if an acquisition is in progress orcomplete or if the status is unknown. This operation does not check theinstrument status. Typically, this operation is called only in a sequenceof calls to other low-level driver operations (such as Initiate). If thedriver cannot query the instrument to determine its state, the operationreturns Status Unknown.

Supported values:

Complete (1) Specifies that the acquisition is complete.

In Progress (0) Specifies that the acquisition is in progress.

Status Unknown (–1) Specifies that the driver cannot query theinstrument to determine its state or thestatus is unknown.

• Get Auto Probe Sense Value—Specifies a variable or property towhich the step assigns the probe attenuation value that the oscilloscopeautomatically senses. After you attach the probe to a channel, the probeuses the returned value as the scaling factor for attenuating the input.If the auto probe sense capability is not enabled, this function returnsthe current manual probe attenuation setting. Use the Channel controlto specify the channel name to perform the operation on. The valuecontrol specifies the property or variable name the step assigns thereturned value to.


Step PropertiesFigure 5 shows the step properties for the IVI Scope step type.

Figure 5. IVI Scope Step Properties


The IVI Scope step type defines the following step properties in addition tothe common custom properties:

• Step.Result.Reading contains the measurement values for the Readand Fetch operations. This property is an array of container, and thesize of the array is equal to the number of channels specified for theRead or Fetch operation. The data type of each element of the array isNI_IviSinglePoint, NI_IviWave or NI_IviWavePair.




• Step.Configuration contains the settings for the Configure operation.The data type of this property is NI_IviDmmConfig.


• Step.Readings contains the settings for the Read and Fetch operations.The data type of this property is NI_IviScopeReadings. The Channelssubproperty is an array of type NI_IviReading.


IVI Fgen StepYou use the IVI Fgen step type to instruct function generators to generatepredefined waveforms or custom waveforms using arbitrary waveformgenerators. The step type supports the following operations.




• Initiate—Initiates signal generation if the instrument is idle.

• Abort—Aborts a previously configured output and returns thefunction generator to the idle state.







• Output Mode—Determines how the function generator produceswaveforms. This setting determines which extension group's functionsand settings to use to configure the waveform the function generatorproduces.

Supported values:

Standard Function (0) Specifies to use standard function settingsto configure the function generator's outputsignals.

Arb Waveform (1) Specifies to use the settings on theWaveforms tab to configure the functiongenerator's output signals.


Sequence (2) Specifies to use the settings on theSequences tab to configure the functiongenerator's output signals.

• Ref Check Source—Specifies the source of the reference clock. Thefunction generator derives frequencies and sample rates that it uses togenerate waveforms from the reference clock.

Support values:

External (1) Specifies the source of the reference clockto be a signal from an external source.

Internal (0) Specifies the source of the reference clockto be a clock signal generated internally.

RTSI Clock (101) Specifies the source of the reference clockto be a signal from the RTSI clock source.

• Arb Sample Rate—Specifies the sample rate of the arbitrarywaveforms that the function generator produces. The units are samplesper second. On function generators with more than one channel, thissetting affects all channels.

• Internal Trigger Rate—Specifies the rate at which the functiongenerator's internal trigger source produces a trigger, in triggers persecond. The Internal Trigger extension supports function generatorsthat can generate output based on an internally generated triggersignal. You can configure the rate at which internal triggers aregenerated. This setting affects instrument behavior when the TriggerSource setting is set to Internal Trigger.

• Auto Stop/Start—Automates the stopping and starting of functiongeneration during the Configure operation. When this setting isenabled, Abort is called before a Configure operation takes place, andInitiate is called at the end of a Configure operation.

• AM Modulation Internal Depth—Specifies the extent of modulationthe function generator applies to the carrier waveform. This settingaffects the behavior of the instrument only when the AM Sourcesetting for a channel is set to AM Internal. The internal depth formodulated waveforms is represented as a percentage.

• AM Modulation Internal Waveform—Specifies the waveform ofthe internal modulating waveform source for AM. This setting affectsthe behavior of the instrument only when the AM Source setting for achannel is set to AM Internal.

Supported values:

DC (6) Selects a DC waveform as the AM internalmodulating waveform source.

Ramp Down (5) Selects a negative ramp waveform as theAM internal modulating waveform source.


Ramp Up (4) Selects a positive ramp waveform as theAM internal modulating waveform source.

Sine (1) Selects a sinusoid waveform as the AMinternal modulating waveform source.

Square (2) Selects a square waveform as the AMinternal modulating waveform source.

Triangle (3) Selects a triangle waveform as the AMinternal modulating waveform source.

• AM Modulation Internal Frequency—Specifies the frequency inhertz of the internal modulating waveform source for AM. This settingaffects the behavior of the instrument only when the AM Sourcesetting for a channel is set to AM Internal.

• FM Modulation Internal Deviation—Specifies the maximumfrequency deviation the function generator applies to the carrierwaveform. This setting affects the behavior of the instrument onlywhen the FM Source setting for a channel is set to FM Internal.

• FM Modulation Internal Waveform—Specifies the waveform of theinternal modulating waveform source for FM. This setting affects thebehavior of the instrument only when the FM Source setting for achannel is set to FM Internal.

Supported values:

DC (6) Selects a DC waveform as the FM internalmodulating waveform source.

Ramp Down (5) Selects a negative ramp waveform as theFM internal modulating waveform source.

Ramp Up (4) Selects a positive ramp waveform as theFM internal modulating waveform source.

Sine (1) Selects a sinusoid waveform as the FMinternal modulating waveform source.

Square (2) Selects a square waveform as the FMinternal modulating waveform source.

Triangle (3) Selects a triangle waveform as the FMinternal modulating waveform source.

• FM Modulation Internal Frequency—Specifies the frequency inhertz of the internal modulating waveform source for FM. This settingaffects the behavior of the instrument only when the FM Source settingfor a channel is set to FM Internal.



The Channels tab contains a list control with the default channels for theselected logical name. You can use the Add and Remove buttons to add newchannels and remove existing channels from the list. You can specifywhether the function generator outputs a signal for the channel by enablingthe channel using the check box within the list control. If you enable thePreserve Existing Channels checkbox, the step adds to or modifies anyexisting channels previously configured. When you uncheck the PreserveExisting Channels check box, the step deletes all previously configuredchannels before configuring the specified channels in the list.




• Output Signal Tab

– Type—Specifies which standard waveform the function generatorproduces. The valid values vary depending on the Output Modesetting on the Basic tab.

When the Output Mode setting is Standard Function, thesupported values are:

DC (6) Selects a DC waveform as the waveformtype.

Ramp Down (5) Selects a negative ramp waveform as thewaveform type.

Ramp Up (4) Selects a positive ramp waveform as thewaveform type.

Sine (1) Selects a sinusoid waveform as thewaveform type.

Square (2) Selects a square waveform as the waveformtype.

Triangle (3) Selects a triangle waveform as thewaveform type.

When the Output Mode setting is Arb Waveform the Type settingspecifies the name of a waveform defined on the Waveforms tab.

When the Output Mode setting is Sequence the Type settingspecifies the name of a sequence defined on the Sequences tab.

– Frequency—Specifies the frequency of the standard waveform inhertz that the function generator produces, or specifies the rate inhertz at which an entire arbitrary waveform is generated.

– DC Offset—Specifies the DC offset of the standard waveformthat the function generator produces, or specifies the offset of thearbitrary waveform in volts that the function generator produces.For standard waveforms, if the Type setting is set to DC, thissetting specifies the DC level the function generator produces. Theunits are volts.

– Amplitude—Specifies the amplitude of the standard waveformthat the function generator produces. When the Type setting is setto DC, this setting does not affect signal output. The units arevolts.

– Gain—Specifies the gain of the arbitrary waveform that thefunction generator produces. This value is unitless.


– Duty Cycle High—Specifies the duty cycle for a squarewaveform. The value is expressed as a percentage.

– Start Phase—Specifies the start phase of the standard waveformthat the function generator produces. When the Type setting is setto DC, this setting does not affect signal output. The units aredegrees.

• Operation Tab

– Output Impedance—Specifies the impedance of the outputchannel in ohms.

– Trigger Source—Specifies the trigger source for the channel.The function generator produces a signal after it receives a triggerfrom the source.

Supported values:

ECL0 (119) Specifies that the function generator waitsfor a trigger on the ECL 0 line beforeproducing an output signal.

ECL1 (120) Specifies that the function generator waitsfor a trigger on the ECL 1 line beforeproducing an output signal.

External (1) Specifies that the function generator waitsfor a trigger on its external trigger inputterminal before producing an output signal.

Internal (3) Specifies that the function generator waitsfor a trigger from its internal trigger sourcebefore producing an output signal.

PXI Star (131) Specifies that the function generator waitsfor a trigger on the PXI Star line beforeproducing an output signal.

RTSI0 (141) Specifies that the function generator waitsfor a trigger on the RTSI 0 line beforeproducing an output signal.








Software (2) Specifies that the function generator waitsfor the Send Software Trigger operation toexecute before producing an output signal.

TTL0 (111) Specifies that the function generator waitsfor a trigger on the TTL 0 line beforeproducing an output signal.








– Operation Mode—Specifies how the function generatorproduces output on a channel.

Supported Values:

Burst (1) Used when the function generator mustproduce a burst of waveform cycles basedon a trigger condition.


Continuous (0) Used when the function generator mustproduce output continuously.

– Burst Count—Specifies the number of waveform cycles that thefunction generator produces after it receives a trigger. The Burstextension group supports function generators capable ofgenerating a discrete number of waveform cycles based on atrigger. The trigger is configured with the Trigger extension group.You can specify the number of waveform cycles to generate whena trigger event occurs. For standard and arbitrary waveforms, acycle is one period of the waveform. For arbitrary sequences, acycle is one complete progression through the generation of alliterations of all waveforms in the sequence. This setting affectsinstrument behavior only when the Operation Mode setting is setto Burst and when the Burst extension is enabled.

• Modulation Tab

– AM Modulation Enabled—Specifies if the function generatorapplies amplitude modulation to the carrier waveform. If thissetting is enabled, the function generator applies amplitudemodulation to the signal that the function generator produces. Inorder to use this setting, the Modulate AM extension must beenabled.

– AM Modulation Source—Specifies the source of the signal thatthe function generator uses as the modulating waveform for AM.This setting affects instrument behavior only when the AMModulation Enabled setting is set to True. In order to use thissetting, the Modulate AM extension must be enabled.

Supported values:

External (1) Specifies a waveform from an externalsource as the modulating waveform forAM.

Internal (0) Specifies an internally generated waveformas the modulating waveform for AM.

– FM Modulation Enabled—Specifies if the function generatorapplies amplitude modulation to the carrier waveform. If thissetting is enabled, the function generator applies amplitudemodulation to the signal that the function generator produces. Inorder to use this setting, the Modulate FM extension must beenabled.

– FM Modulation Source—Specifies the source of the signal thatthe function generator uses as the modulating waveform for FM.This setting affects instrument behavior only when the FMModulation Enabled setting is set to True. In order to use thissetting, the Modulate FM extension must be enabled.


Supported values:

External (1) Specifies a waveform from an externalsource as the modulating waveform forFM.

Internal (0) Specifies an internally generated waveformas the modulating waveform for FM.

Waveforms TabThe following figure shows the Waveforms tab for the Configureoperation.

The Waveforms tab contains a list control of defined waveforms. You canuse the Add and Remove buttons to add new waveforms and removeexisting waveforms from the list. If you enable the Preserve ExistingWaveforms checkbox, the step adds to or modifies any existing waveformspreviously configured. When you uncheck the Preserve ExistingWaveforms check box, the step deletes all previously configuredwaveforms before configuring the specified waveform in the list.


The Waveforms tab for the Configure operation contains the followingwaveform specific controls:

• Name—Specifies the name of the arbitrary waveform.

• Source—Selects the source of the arbitrary waveform. The waveformsource can be a valid ASCII or binary file format, or a waveformreturned from an expression that TestStand evaluates. The Filenamesetting specifies the relative or absolute file path. The Data Sourcesetting specifies the expression that TestStand evaluates.

Supported values:

Use Data Source Specifies the arbitrary waveform source tobe an expression that TestStand evaluates.

2 Byte Integer Specifies the arbitrary waveform source tobe a file with 2-byte integer data.

4 Byte Integer Specifies the arbitrary waveform source tobe a file with 4-byte integer data.

ASCII File Specifies the arbitrary waveform source tobe a file with delimited ASCII data.

• Data Source—Specifies the expression that TestStand evaluates whenthe Source setting is Use Data Source. When TestStand evaluates theexpression at run-time, the expression must return an array of number.If the expression specifies a variable or property name, you can use theLoad button to import data from a file into the variable or property. TheClear button sets the specified array property to empty. The Viewbutton displays the data in the array property in a graph.

The default value for the Data Source setting isStep.Configuration.Waveforms, which is an array of waveforms. Eachelement of the array represents the data for the waveforms specified inthe list control.

• Filename—Specifies the source file for the arbitrary waveform whenthe Source setting is a file. Files can be ASCII files with values that aredelimited by a variety of characters including, but not limited to theCarriage return, comma, and semicolon. Additionally, files can be2-byte or 4-byte integer binary files. Valid binary files contain adifferent entry every x bytes, where x is 2 or 4 depending on the file.These binary files are not explicitly delimited by anything exceptspace. For instance, if we had a 4-byte integer file containing 5 points,the data might look like this:

Address Value

0x0000 0x00000001

0x0004 0x00000002

0x0008 0x00000003


0x000C 0x00000004

0x0010 0x00000005

• Auto Normalize Mode—Specifies how to normalize an arbitrarywaveform, if at all. Normalizing a waveform transforms the waveformso that the normalized points are between the values –1 and 1. If theoffset is removed, then the values of the normalized points will spanthe interval –1 to 1.

Supported values:

No Auto Normalize (0) Selects no automatic normalization ofwaveform data.

Normalize (1) Selects automatic normalization ofwaveform data to be between –1 and 1.

Normalize And Remove Offset (2)Specifies automatic normalization ofwaveform data, which forces data points tospan the interval –1 to 1.


Sequences TabThe following figure shows the Sequences tab for the Configure operation.

The Sequences tab contains a list control of defined sequences. You can usethe Add and Remove buttons to add new sequences and remove existingsequences from the list. If you enable the Preserve Existing Sequencescheckbox, the step adds to or modifies any existing sequences previouslyconfigured. When you uncheck the Preserve Existing Sequences checkbox, the step deletes all previously configured sequences beforeconfiguring the specified sequence in the list.

The Sequences tab for the Configure operation contains the followingsequence specific controls:

• Name—Specifies the name of the sequence.

• Sequence Items—Specifies a list of waveforms and how many timesto generate each waveform. You can use the Add, Remove, Up andDown buttons to edit the list of waveforms in the list.


When you select a list item the following controls allow you to end theselected item.

– Waveform—Specifies the name of a waveform defined on theWaveforms tab.

– Iterations—Specifies the number of times that the associatedWaveform appears in the sequence for this sequence item. TheIterations setting must be less than or equal to the maximumnumber of iterations that the function generator allows.



• Standard Function—Supports extensions for function generators thatcan produce manufacturer-supplied periodic waveforms.


• Arb Waveform—Supports extensions for function generators capableof producing user-defined arbitrary waveforms.

• Arb Sequences—Supports extensions for function generators capableof producing sequences of arbitrary waveforms.

• Arb Frequency—Supports extensions for function generators capableof producing arbitrary waveforms and setting the rate at which anentire waveform buffer is generated.

• Modulate AM—Supports extensions for function generators that canapply amplitude modulation to an output signal.

• Modulate FM—Supports extensions for function generators that canapply frequency modulation to an output signal.

• Burst—Supports extensions for function generators capable ofgenerating a discrete number of waveform cycles based on a trigger.

• Trigger—Supports extensions for function generators capable ofconfiguring a trigger.

• Internal Trigger—Supports extensions for function generators thatcan generate output based on an internally generated trigger signal.

• Software Trigger—Supports extensions for function generators thatcan generate output based on a software trigger signal.


InitiateInitiates signal generation if the instrument is idle. If the function generatoris in the idle state, this operation moves the function generator to the outputgeneration state. If the function generator is already in the outputgeneration state, this operation does nothing.

The instrument must be in the generation state after you call the Initoperation. Also, you must be able to configure the output of the functiongenerator regardless of whether the function generator is in the idle state orthe generation state. You are only required to call the Initiate operation ifyou abort signal generation by calling the Abort operation.

Many function generators constantly generate an output signal, and do notrequire you to initiate signal generation. If a function generator is alwaysoutputting the currently configured signal, this operation does nothing.


Some function generators require that you abort signal generation prior toconfiguring the instrument and initiate signal generation after configuringthe instrument. The specific drivers for these types of instruments mustcompensate for this restriction and allow you to configure the instrumentwithout requiring the user to call the Abort and Initiate operations. Forthese types of instruments, there is often a significant performance increaseif you configure the output while the instrument is not generating a signal.

You are not required to call the Initiate and Abort operations. If you chooseto call these operations, it has no impact on interchangeability. You canchoose to use these operations if you want to optimize the application forinstruments that exhibit increased performance when output configurationis performed while the instrument is not generating a signal.

AbortAborts a previously configured output and returns the function generator tothe idle state. If the function generator is in the output generation state, thisoperation moves the function generator to the idle state. If the functiongenerator is already in the idle state, the operation does nothing.

You can configure the output of the function generator regardless ofwhether the function generator is in the idle state or the generation state.You are not required to call Abort prior to configuring the output of thefunction generator.

Many function generators constantly generate an output signal and do notrequire you to abort signal generation prior to configuring the instrument.If a function generator's output cannot be aborted, for example, the functiongenerator cannot stop generating a signal, this operation does nothing.

Some function generators require that you abort signal generation prior toconfiguring the instrument. The specific drivers for these types ofinstruments must compensate for this restriction and allow you to configurethe instrument without requiring you to call the Abort operation. For thesetypes of instruments, there is often a significant performance increase ifyou configure the output while the instrument is not generating a signal.

You are not required to call the Initiate and Abort operations. If you chooseto call these operations in an application program, it has no impact oninterchangeability. You can choose to use these operations if you want tooptimize the application for instruments that exhibit increased performancewhen output configuration is performed while the instrument is notgenerating a signal.


Send Software TriggerSends a software trigger command to trigger the instrument. This operationsends a software trigger when a Trigger Source setting is set to SoftwareTrigger. To use this operation, the Software Trigger extension must beenabled.





• Get Max Num Waveforms—Specifies a variable or property towhich the step assigns the maximum number of arbitrary waveformsthat the function generator allows.

• Get Max Waveform Size—Specifies a variable or property to whichthe step assigns the maximum number of points the function generatorallows in an arbitrary waveform.

• Get Min Waveform Size—Specifies a variable or property to whichthe step assigns the minimum number of points the function generatorallows in an arbitrary waveform.

• Get Waveform Quantum—Specifies a variable or property to whichthe step assigns the quantum value that the function generator allows.

• Get Max Loop Count—Specifies a variable or property to which thestep assigns the maximum number of times the function generator canrepeat an arbitrary waveform in a sequence.

• Get Max Num Sequences—Specifies a variable or property to whichthe step assigns the maximum number of sequences that the functiongenerator allows.

• Get Max Sequence Length—Specifies a variable or property towhich the step assigns the maximum number of arbitrary waveformsthe function generator allows in a sequence.

• Get Min Sequence Length—Specifies a variable or property to whichthe step assigns the minimum number of arbitrary waveforms thefunction generator allows in a sequence.


Step PropertiesFigure 6 shows the step properties for the IVI Fgen step type.

Figure 6. IVI Fgen Step Properties


The IVI Fgen step type defines the following step properties in addition tothe common custom properties:




• Step.Configuration contains the settings for the Configure operation.The data type of this property is NI_IviFgenConfig.



IVI DC Power Supply StepYou use the IVI DC Power Supply step type to instruct power supplies tocontrol the output voltages and currents, and measure output values at theoutput terminals. The step type supports the following operations.




• Measure—Takes a measurement on the output signal and returns themeasured value.

• Initiate—Makes the power supply wait for a trigger.







The Channels tab contains a list control with the default channels for theselected logical name. You can use the Add and Remove buttons to add newchannels and remove existing channels from the list. You can specifywhether the power supply outputs a signal for the channel by enabling thechannel using the check box within the list control. If you enable thePreserve Existing Channels checkbox, the step adds to or modifies anyexisting channels previously configured. When you uncheck the PreserveExisting Channels check box, the step deletes all previously configuredchannels before configuring the specified channels in the list.




• Voltage Level—Specifies the voltage level in volts that the DC powersupply attempts to generate.

• Output Range Mode—Specifies how to configure the power supply'soutput range on a channel.

Supported values:

Automatic (–1) Chooses the Voltage Level setting to beused to configure the range of theinstrument.

Use Current Range (0) Chooses the Current Range setting to beused to configure the range of theinstrument.

Use Voltage Range (1) Chooses the Voltage Range setting to beused to configure the range of theinstrument.

• Voltage Range—Specifies the maximum voltage value of theinstrument if Output Range Mode is set to Use Voltage Range. Settinga voltage range can invalidate a previously configured current range.

• Current Range—Specifies the maximum current value of theinstrument if Output Range Mode is set to Use Current Range. Settinga current range can invalidate a previously configured voltage range.

• Current Limit Behavior—Specifies the behavior of the power supplywhen the output current is equal to or greater than the value of theCurrent Limit setting.

Supported values:

Current Regulate (0) Indicates the output voltage restriction. Thepower supply restricts the output voltage sothat the output current is not greater thanthe value of the Current Limit setting.

Current Trip (1) Indicates the disabling output voltage. Thepower supply disables the output when theoutput current is equal to or greater than thevalue of the Current Limit setting.

• Current Limit—Specifies the output current limit in amperes. Thevalue of the Current Limit Behavior setting determines the behavior ofthe power supply when the output current is equal to or greater than thevalue of the Current Limit setting.


• OVP Enabled—Specifies if the power supply provides OvervoltageProtection. If this property is set to True, the power supply disables theoutput when the output voltage is greater than or equal to the value ofthe OVP Limit setting.

• OVP Limit—Specifies the maximum voltage in volts that the powersupply allows. If the OVP Enabled setting is set to True, the powersupply disables the output when the output voltage is greater than orequal to the value of the OVP Limit setting. If the OVP Enabled settingis set to False, the OVP Limit setting does not affect the behavior of theinstrument.

• Trigger Source—Specifies the trigger source. After you call Initiate,the power supply waits for a trigger event from the source you specifywith the Trigger Source setting. After a trigger event occurs, the powersupply changes the voltage level to the value of the Triggered VoltageLevel setting and the current limit to the value of the Triggered CurrentLimit setting.

Supported values:

Software (2) Indicates that the power supply waits forthe Send Software Trigger operation toexecute before changing the output signal.

ECL0 (11) Indicates that the power supply waits for atrigger on the ECL 0 line before changingthe output signal.

ECL1 (12) Indicates that the power supply waits for atrigger on the ECL 1 line before changingthe output signal.

External (1) Indicates that the power supply waits for anexternal trigger before changing the outputsignal.

Immediate (0) Indicates that the power supply does notwait for a trigger before changing theoutput signal.

PXI Star (13) Indicates that the power supply waits for atrigger on the PXI STAR line beforechanging the output signal.

RTSI0 (14) Indicates that the power supply waits for atrigger on the RTSI 0 line before changingthe output signal.








TTL0 (3) Indicates that the power supply waits for atrigger on the TTL 0 line before changingthe output signal.








• Triggered Current Limit—Specifies the value in amperes to whichthe power supply sets the current limit after a trigger event occurs.After you call Initiate, the power supply waits for a trigger event fromthe source you specify with the Trigger Source setting. After a trigger


event occurs, the power supply sets the current limit to the value of theTriggered Current Limit setting. After a trigger occurs, the value of theCurrent Limit setting reflects the new value to which the current limithas been set.

• Triggered Voltage Level—Specifies the value in volts to which thepower supply sets the voltage level after a trigger event occurs. Afteryou call Initiate, the power supply waits for a trigger event from thesource you specify with the Trigger Source setting. After a triggerevent occurs, the power supply sets the voltage level to the value of theTriggered Voltage Level setting.

After a trigger occurs, the value of the Voltage Level setting reflects thenew value to which the voltage level has been set.




• Trigger -—Supports extensions for DC power supplies that canchange the voltage at the output terminals based on a Trigger event.

• Software Trigger—Supports extensions for DC power supplies thatcan change the voltage at the output terminals based on the SoftwareTrigger operation.

• Measurement—Supports extensions for DC power supplies that canmake measurements, such as voltage and current measurements, at theoutput terminals.


MeasureThe Measure operation takes a measurement on the output signal andreturns the measured value. The Measure operation causes a voltage and/orcurrent measurement to be taken at the output terminals. The Measurementextension must be enabled before using this operation. The returned valueis the actual voltage or current reading.


Channels TabThe following figure shows the Measure operation.

The Channels tab contains a list control with the default channels for theselected logical name. You can use the Add and Remove buttons to add newchannels and remove existing channels from the list. You can specifywhether the power supply measures the output for the channel by enablingthe channel using the check box within the list control.

The Channels tab for the Measure operation contains the following channelspecific controls:

• Name—Specifies the name of the channel to read. The channel namemust be a valid virtual channel name as defined by the IVIconfiguration for the logical name being used.


• Measurement Type—Specifies the type of data to retrieve from theoscilloscope.

Supported values:

Current (0) Indicates that the current is measured at theoutput terminals.

Voltage (1) Indicates that the voltage is measured at theoutput terminals.

• Measurement Destination—Specifies a variable or property to whichthe step assigns the measurement value. The data type of the variableor property must be Number or NI_IviSinglePoint. The defaultconfiguration for the step specifies Step.Result.Reading as thedestination. This property is an array of container, and the size of thearray is equal to the number of channels specified for the Measureoperation. When you edit the step, the step automatically resized thearray. If you do not specify Step.Result.Reading as the destination,TestStand still copies the measurement value to the Data subpropertyin each array element at runtime.

InitiateMakes the power supply wait for a trigger. If the power supply is notcurrently waiting for a trigger, this operation causes the power supply towait for a trigger. If the power supply is already waiting for a trigger, thisoperation does nothing.

AbortCancels the wait for a trigger. If the power supply is waiting for a trigger tochange the output signal, this operation returns the power supply to theignore triggers state.

If the power supply is not waiting for a trigger, this operation does nothing.

Send Software TriggerUpdates the voltage level and current limit when a DC power supply is inthe wait for trigger state. This operation sends a software trigger when theTrigger Source setting is set to Software. After the trigger occurs, thevoltage level and current limit are updated with the values of triggeredcurrent limit and the triggered voltage level. To use this operation, theSoftware Trigger extension must be enabled.

Reset Output ProtectionResets the power supply's output protection on a specific channel after anovervoltage or overcurrent condition occurs. An overvoltage conditionoccurs when the output voltage is equal to or greater than the value of the


OVP Limit setting and the OVP Enabled setting is set to True. Anovercurrent condition occurs when the output current is equal to or greaterthan the value of the Current Limit setting and the Current Limit Behaviorsetting is set to Current Trip.

When either an overvoltage condition or an overcurrent condition occurs,the output protection of the power supply disables the output. Once theoutput protection is reset, the power supply resumes generating a powersignal.

You can use the Query Output State operation on the Get Information tabto determine if the power supply is in an overvoltage or overcurrent state.All specific drivers might not support the Reset Output Protectionoperation.





• Channel Name—Specifies the name of the channel to operate on.The channel name must be a valid virtual channel name as defined bythe IVI configuration for the logical name being used.

• Query Max Current Limit—Query the maximum programmablecurrent limit that the power supply accepts for a particular voltage levelon a channel.

– Voltage Level—Specifies the voltage level for which you want tofind the maximum programmable current limit.

– Max Current Limit—Specifies a variable or property to whichthe step assigns the maximum programmable current limit.

• Query Max Current Limit—Query the maximum programmablevoltage level that the power supply accepts for a particular current limiton a channel.

– Voltage Level—Specifies the current limit for which you want tofind the maximum programmable voltage level.

– Max Voltage Level—Specifies a variable or property to whichthe step assigns the maximum voltage level.

• Query Output State—Query the value of a specified DC powersupply output state.

– Output State—Specifies the output state to query.

Supported values:

Constant Current (1) Determines if an instrument is in constantcurrent mode. A constant current conditionoccurs when the output current is equal tothe value of the Current Limit setting andthe Current Limit Behavior setting is set toCurrent Regulate.

Constant Voltage (0) Determines if an instrument is in constantvoltage mode. A constant voltage conditionoccurs when the output voltage is equal tothe value of the Voltage Level setting andthe current is less than or equal to the valueof the Current Limit setting.

Over Current (3) Determines if an overcurrent conditionexists in the instrument. An overcurrentcondition occurs when the output current isequal to or greater than the value of theCurrent Limit setting and the Current LimitBehavior property is set to Current Trip.

Over Voltage (2) Determines if an overvoltage conditionexists in the instrument. An overvoltage


condition occurs when the output voltage isequal to or greater than the value of theOVP Limit setting and the OVP Enabledsetting is set to True.

Unregulated (4) Determines if an unregulated conditionexists in the instrument. An unregulatedcondition occurs when the output voltage isless than the value of the Voltage Levelsetting and the current is less than the valueof the Current Limit setting.

– Value—Specifies a Boolean variable or property to which the stepassigns the output state.

When either an overvoltage condition or an overcurrent conditionoccurs, the power supply's output protection disables the output. If thepower supply is in an overvoltage or overcurrent state, it does notproduce power until the output protection is reset. The Reset OutputProtection operation resets the output Protection. Once the outputprotection is reset, the power supply resumes generating a powersignal.

Some drivers might not support the querying of all the output states.Reset Output Protection might not be supported with all drivers.


Step PropertiesFigure 7 shows the step properties for the IVI DC Power Supply step type.

Figure 7. IVI DC Power Supply Step Properties


The IVI DC Power Supply step type defines the following step propertiesin addition to the common custom properties:

• Step.Result.Reading contains the measurement values for the Measureoperation. The property data type is an array of NI_IviSinglePoint.





• Step.Readings contains the settings for the Measure operation.


IVI Tools StepYou can use the IVI Tools step type to perform low-level operations on aninstrument. The step type supports the following operations:

• Get Session Info—Retrieve low-level session references and APIclass handles to the IVI instrument.

• Show Soft Front Panel—Displays the soft front panel for the tool.

• Hide Soft Front Panel—Hides the soft front panel for the tool.

• Init—Initializes the driver or I/O resource for the session.

• Close—Closes (uninitializes) the IVI session.

• Reset—Places the instrument in a known state.

• Self Test—Causes the instrument to perform a self-test.

• Revision Query—Queries the instrument driver and instrument forrevision information.

• Error Query—Returns instrument-specific error information.

• Get Error Info—Returns error information for the last IVI error for asession.

• Set/Get/Check Attributes—Allows you to set, query or verify thevalue of attributes.

Get Session InfoThe Get Session Info operation allows you to get the low-level sessionmanager instrument session, and the API class handles and references tothe IVI instrument.


The following figure shows the Get Session Info operation.

The Get Session Info operation contains the following controls:

• Session Manager Reference—Specifies a variable or property towhich the step assigns a COM pointer to the InstrSession object thatthe Session Manager creates for the specified logical name. You canuse an InstrSession object to obtain an instrument API handle orreference.

• C Driver Handle—Specifies a variable or property to which the stepassigns the C-based class API handle for the specified logical name.You use a class handle to control an instrument via an IVI class driver.

• COM Driver Reference—Specifies a variable or property to whichthe step assigns the COM pointer to the class API object for thespecified logical name. You use a class reference to control aninstrument via an IVI class COM interface.

• ActiveX Control Reference—Specifies a variable or property towhich the step assigns the COM pointer to the Measurment Studio forVisual Basic ActiveX control for the class specified by the logicalname. You use a control reference to interact with the instrument viathe Measurment Studio COM interface.


Note For the current version of IVI, do not pass an instrument handle between operatingsystem processes because instrument driver handles you obtain in one process do notfunction in any other process.

InitThe Init operation initializes the driver or I/O resource for the session.Normally a session automatically initializes an instrument session when anexecution runs an IVI step.

The following figure shows the Init operation.

The Init operation contains the following controls:

• Perform Id Query—Specifies whether the init operation performs anidentification query on the instrument.

• Reset—Specifies whether the init operation also resets the instrument.A reset operation to place the instrument in a known state. In an IEEE488.2 instrument, the Reset operation sends the command string“*RST” to the instrument. Reset also sends the default setup


commands to the instrument to configure settings for the properoperation of the instrument driver.

• Additional Initialization Options—Specifies additional optionsseparated by comma that are supported by IVI.

Some examples include:

Simulate=1

RangeCheck=1

QueryInstrStatus=1

Cache=1

RecordCoercions=1

InterchangeCheck=1

UseSpecificSimulation=1

• ReInitialization Action—Specifies the behavior of the Init operationif Init is being called on a previously opened instrument session.

Supported values:

Noop (0) Specifies that if there is an active session tothe current logical name, calling Init haveno effect.

Close and Init (1) Specifies that if there is an active session tothe current logical name, that session isclosed and a new one is opened.

Raise Error (2) Specifies that if there is an active session tothe current logical name, calling Init causesan error.

CloseThe Close operation closes (uninitializes) the IVI session for the specifiedlogical name. Normally, the instrument session for a logical nameautomatically closes when the last execution closes that ran an IVI step.

ResetThe Reset operation places the instrument in a known state. In an IEEE488.2 instrument, the Reset operation sends the command string “*RST” tothe instrument. Reset also sends the default setup commands to theinstrument to configure settings for the proper operation of the instrumentdriver.

Self TestThe Self Test operation causes the instrument to perform a self-test. Theoperation waits for the instrument to complete the test. It then queries theinstrument for the results and returns them.


The following figure shows the Self Test operation.

The Self Test operation contains the following controls:

• Test Result—Specifies a variable or property to which the step assignsthe numeric result from the self-test. Returns 0 for no error (testpassed).

• Test Message—Specifies a variable or property to which the stepassigns the self-test status message.


Revision QueryThe Revision Query operation queries the instrument driver and instrumentfor current revisions. The operation returns the revision of the instrumentdriver and the revision of the firmware for the instrument you are using.

The following figure shows the Revision Query operation.

The Revision Query operation contains the following controls:

• Driver Revision—Specifies a variable or property to which the stepassigns the revision information for the instrument driver.

• Instrument Revision—Specifies a variable or property to which thestep assigns the revision information for the instrument firmware.

Error QueryThe Error Query operation queries the instrument and returns theinstrument-specific error information. You call use this operation afteranother operation in the instrument driver returns theIVI_ERROR_INSTR_SPECIFIC error code. The driver returnsIVI_ERROR_INSTR_SPECIFIC when the instrument’s status register


indicates that the instrument’s error queue is not empty. The Error Queryoperation extracts the first error out of the instrument’s error queue. Forinstruments that have status registers but no error queue, the driversimulates an error queue in software.

The following figure shows the Error Query operation.

The Error Query operation contains the following controls:

• Error Code—Specifies a variable or property to which the stepassigns the error code returned from the instrument error query.

• Error Message—Specifies a variable or property to which the stepassigns the readable description of the error code.


Get Error InfoThe Get Error Info operation returns error information for the last IVI errorfor a given IVI session. The operation retrieves and then clears the errorinformation for the instrument session. The error information includes aprimary error code, a secondary error code, and an error elaboration string.The error information is the same as the values held in the following IVIattributes:

IVI_ATTR_PRIMARY_ERROR

IVI_ATTR_SECONDARY_ERROR

IVI_ATTR_ERROR_ELABORATION

The following figure shows the Get Error Info operation.

The Error Query operation contains the following controls:

• Primary Error Code—Specifies a variable or property to which thestep assigns primary error code for the session or execution thread. Avalue of VI_SUCCESS (0) indicates that no error occurred. A positivevalue indicates a warning. A negative value indicates an error.


• Secondary Error Code—Specifies a variable or property to which thestep assigns the secondary error code for the session or executionthread. If the primary error code is a nonzero value, the secondary errorcode can further describe the error or warning condition. A value ofVI_SUCCESS (0) indicates no further description.

• Error Elaboration—Specifies a variable or property to which the stepassigns the error elaboration string for the session or execution thread.If the primary error code is a nonzero value, the elaboration string canfurther describe the error or warning condition.

Set/Get/Check AttributesThe Set/Get/Check Attributes operation allows you to set the value ofattributes, query the value of attributes, and verify that a values you specifyfor attributes are valid.

The following figure shows the Set/Get/Check Attributes operation.


The list control contains the attributes you are operating on. You can use theAdd and Remove buttons to add new attributes and remove existingattributes from the list.

The Attribute section on the dialog box for the operation contains thefollowing attribute specific controls:

• Operation—Specifies whether the step gets the value, set the value orverifies the value of the attribute.

• Id Or Name—Specifies the index of the IVI attribute or the name ofthe IVI attribute.

• Channel Name—Specifies the name of the channel to operate on.The channel name must be a valid virtual channel name as defined bythe IVI configuration for the logical name being used. This setting onlyapplies to attributes of channels.

• Value—For Set and Check operations, the control specifies theattribute value to assign or verify. For Get operations, the controlspecifies a variable or property to which the step assigns the returnedvalue.


Step PropertiesFigure 8 shows the step properties for the IVI Tools step type.

Figure 8. IVI Tools Step Property

The IVI Tools step type defines the following step properties in addition tothe common custom properties:





• Step.Init contains the settings for the Init operation.

• Step.SelfTest contains the settings for the Self Test operation.

• Step.SessionInfo contains the settings for the Get Session Infooperation.


• Step.RevisionQuery contains the settings for the Get Revision Queryoperation.

• Step.ErrorQuery contains the settings for the Error Query operation.

• Step.ErrorInfoInit contains the settings for the Get Error Infooperation.

• Step.Attributes contains the settings for the Set/Get/Check Attributesoperation.

IVI STEP YPES - National Instruments©National Instruments Corporation 5 IVI Step Types Editing an...

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