Application Note

Because pressure is one of themore widely measured param-eters in process industries, it is acritical function of a document-ing process calibrator. Fluke’spressure modules cover a widerange of pressures and maintainaccuracy over a wide tempera-ture range, from 0°C to 50°C(32° F to 122°F). The pressuremeasurement portion of theFluke 700 Series DocumentingProcess Calibrators is separatefrom the main unit to facilitateconnection to fixed or bulkyequipment and to provide mul-tiple pressure ranges for a singlecalibrator.

A large selection of gage anddifferential modulesA family of 27 pressure modulescovers the most common pres-sure calibrations from 0-10" H2O(0-2.5 kPa) to 0-10,000 psi(0-70,000 kPa).

Gage pressure modules haveone pressure fitting and measurethe process pressure with re-spect to atmospheric pressure.Differential pressure moduleshave two pressure fittings andmeasure the difference betweenthe applied pressure on the highfitting versus the low fitting.Each module is clearly labeledfor range, overpressure specifi-cation, and materials compatibil-ity. A metric adapter is includedwith all but the P29 through P31high pressure modules. Figure 1shows the two types.

Quick and easy measurementsFluke 700 Series pressure mod-ules are easy to operate. Tomeasure pressure, the techniciandisconnects the pressure mea-suring transmitter from theprocess, plumbs the pressuremodule to a pressure source, andconnects the pressure modulecable to the calibrator. Pressure

is applied, measured by the pres-sure module, and displayed digi-tally on the calibrator. At thetouch of a button, the pressuremay be displayed in any of 10different pressure units. Becausethe 700 Series calibrators cancapture readings electronically,there’s no need to write downresults. The calibrators automati-cally time-stamp and store allsaved measurements, savingtime, and eliminating errors asso-ciated with making manual nota-tions in the field. These self-documenting capabilities areimportant in ensuring accuratemaintenance. They are also veryhelpful in collecting calibrationdata to support compliance withdocumentation standards, includ-ing those established by OSHA,the FDA, the EPA, and ISO 9000.

Pressure module performanceFluke 700 Series pressure mod-ules are highly accurate, withsimply stated specifications thatapply from 0% to 100% of fullspan and from 0°C to 50°C (32°Fto 122°F)—a factor that sets themapart from other pressure calibra-tors. Most ranges have total un-certainties of 0.05% of full scale(see Table 1, page 2).

This performance is possiblethrough the innovative applica-tion of mathematics and micro-processor power. Fluke pressuremodules have silicon piezo-resistor sensors which consist ofa resistive bridge fabricated in asilicon diaphragm. Pressure ap-plied to the diaphragm causes achange in the balance of thebridge which is proportional tothe applied pressure. The bridgebalance change is not linear andis very sensitive to temperature.However, since these effects arequite stable with time andthrough repetitive changes ofcondition, the sensors can bevery accurate in measuring pres-sure over a wide temperaturerange, provided they are care-fully characterized.

During manufacture, Flukepressure modules are character-ized by reading temperature andpressure at more than 100points. A least-squares regres-sion is used to calculate the coef-ficients of polynomial expressionfor pressure. The coefficients,unique to that pressure module,are stored in the module’smemory.

Fluke 700 SeriesPressure Modules

Figure 1. Gage and Differential pressure modules

Advanced Test Equipment Rentalswww.atecorp.com 800-404-ATEC (2832)

®

Established 1981

2 Fluke Corporation 700 Series Pressure Modules

Each module has its ownmicroprocessor, allowing it torun the measurement circuitryand to communicate digitallywith the calibrator. When con-nected to the calibrator, the coef-ficients are uploaded from thepressure module to the calibrator.Then, when pressure measure-ments are made, raw sensorvalues for pressure and tempera-ture are digitally loaded to thecalibrator, where the raw sensorvalues and coefficients aremanipulated to derive and dis-play the pressure reading. Thisinnovative technique providesseveral benefits:1. Digital communication elimi-

nates errors due to poorconnections and electricalinterference.

2. The modules are inherentlytemperature-compensatedfrom 0°C to 50°C (32°F to122°F), with no derating fortemperature effects.

Figure 2. 700 Series Pressure Modules are overmolded with protective urethane and sealedagainst dirt, dust and moisture. All fittings are made of 316 stainless steel or Hastelloy C276and have internal mechanical supports

3. The modules are fully inter-changeable because all signalprocessing is handled in thepressure module itself andthen communicated to thecalibrator in digitized form.Modules are calibrated inde-pendently of the calibrator,and can be used with any 700Series calibrator. Each modulehas its own serial number tofacilitate traceability.

Sensor protection inisolated modulesMany of these modules (see Table1) incorporate a stainless steeldiaphragm to isolate the sensor.With these modules, any mediumthat is compatible with stainlesssteel can be used on the highside of the module.

Rugged constructionThe pressure modules are de-signed to operate accurately andreliably despite the rough han-dling and harsh environmentalconditions often found in processplants. A urethane overmoldingprotects against shock if a mod-ule is accidentally dropped andalso seals against dirt, dust, andmoisture. The module case isheld together with screws con-nected to brass-reinforced seats,and all the pressure fittings,which are constructed of 316stainless steel, have internalmechanical supports. Pressureconnections are 1/4" NPT. ABSP/ISO adapter is also providedon all but the P29, P30 and P31.

Small and lightweightSince process technicians mightneed to carry two or more pres-sure modules along with thecalibrator, the modules are smalland lightweight.

Remote sensorA one-meter cable between thepressure module and calibratorreduces the length of connectingtubing to the pressure source.The remote pressure head alsoprovides an extra margin ofsafety and convenience by re-moving the calibrator and opera-tor from the pressure source.

Table 1. Pressure specifications

700 Series Pressure Modules Fluke Corporation 3

1Total uncertainty, % of full span for temperature range 0°C to +50°C, one year interval. Total uncertainty, 1.0% of full span for temperaturerange -10°C to 0°C, one year interval.2“Dry” indicates dry air or non-corrosive gas as compatible media. “316 SS” indicates media compatible with Type 316 Stainless Steel.“C276” indicates media compatible with Hastelloy C276.Use of pressure zero is required prior to measurement or source.Pressure units available are: psi, kPa, bar, in. Hg, mm Hg, in. H2O (@4°C), ft. H2O (@4°C), kg/cm2, in. H2O (@60°F), mm. H2O (@4°C).Maximum overpressure specification includes common mode pressure.Modules are rated.Metric adapter(s): 1/4" NPT female to male BSP/ISO 1/4-19, tapered thread, included with all modules except P29, P30, and P31.Effective October 1996, all modules include a NIST traceable certificate and test data.Notes for 701 and 702 users only: Internal software V1.3 or later required. kg/cm2, in. H2O (@60°F), mm H2O units not available.Not compatible with the PA and PV modules. Resolution in inches H2O and kPa may vary from that shown in table.

Typical Total1 High2 Low2 Max over-Range (approx)/ uncertainty uncertainty side side Fitting pressure

Model Range/Resolution Resolution 1 year 1 year media media material (x nominal)

Differential

FLUKE-700P01 10 in. H2O / 0.01 2.5 kPa / 0.002 0.10% 0.30% Dry Dry 316 SS 3xFLUKE-700P02 1 psi / 0.0001 6900 Pa / 0.7 0.10% 0.30% Dry Dry 316 SS 3xFLUKE-700P22 1 psi / 0.0001 6900 Pa / 0.7 0.05% 0.15% 316 SS Dry 316 SS 3xFLUKE-700P03 5 psi / 0.0001 34 kPa / 0.001 0.04% 0.10% Dry Dry 316 SS 3xFLUKE-700P23 5 psi / 0.0001 34 kPa / 0.001 0.02% 0.05% 316 SS Dry 316 SS 3xFLUKE-700P04 15 psi / 0.001 103 kPa / 0.01 0.03% 0.07% Dry Dry 316 SS 3xFLUKE-700P24 15 psi / 0.001 103 kPa / 0.01 0.02% 0.05% 316 SS Dry 316 SS 3x

Gage

FLUKE-700P05 30 psi / 0.001 207 kPa / 0.01 0.02% 0.05% 316 SS N/A 316 SS 3xFLUKE-700P06 100 psi / 0.01 690 kPa / 0.07 0.02% 0.05% 316 SS N/A 316 SS 3xFLUKE-700P07 500 psi / 0.01 3400 kPa / 0.1 0.02% 0.05% 316 SS N/A 316 SS 3xFLUKE-700P08 1000 psi / 0.1 6900 kPa / 0.7 0.02% 0.05% 316 SS N/A 316 SS 3xFLUKE-700P09 1500 psi / 0.1 10 MPa / 0.001 0.02% 0.05% 316 SS N/A 316 SS 2x

Absolute (not compatible with Fluke 701 or 702)

FLUKE-700PA3 5 psi / 0.0001 34 kPa / 0.001 0.03% 0.07% 316 SS N/A 316 SS 3xFLUKE-700PA4 15 psi / 0.001 103 kPa / 0.01 0.02% 0.05% 316 SS N/A 316 SS 3xFLUKE-700PA5 30 psi / 0.001 207 kPa / 0.01 0.02% 0.05% 316 SS N/A 316 SS 3xFLUKE-700PA6 100 psi / 0.01 690 kPa / 0.07 0.02% 0.05% 316 SS N/A 316 SS 3x

Vacuum (not compatible with Fluke 701 or 702)

FLUKE-700PV3 -5 psi / 0.0001 -34 kPa / 0.001 0.02% 0.05% 316 SS Dry 316 SS 3xFLUKE-700PV4 -15 psi / 0.001 -103 kPa / 0.01 0.02% 0.05% 316 SS Dry 316 SS 3x

Dual

FLUKE-700PD2 ±1 psi / 0.0001 ± 6900 Pa / 0.7 0.07% 0.20% 316 SS Dry 316 SS 3xFLUKE-700PD3 ±5 psi / 0.0001 ±34 kPa / 0.001 0.03% 0.07% 316 SS Dry 316 SS 3xFLUKE-700PD4 ±15 psi / 0.001 ±103 kPa / 0.01 0.03% 0.07% 316 SS Dry 316 SS 3xFLUKE-700PD5 -15/30 psi / 0.001 -100/206 kPa / 0.01 0.03% 0.07% 316 SS N/A 316 SS 3xFLUKE-700PD6 -15/100 psi / 0.01 -100/690 kPa / 0.07 0.03% 0.07% 316 SS N/A 316 SS 3xFLUKE-700PD7 -15/200 psi / 0.01 -100/1380 kPa / 0.1 0.03% 0.07% 316 SS N/A 316 SS 3x

High

FLUKE-700P29 3000 psi / 0.1 20.6 M Pa / 0.001 0.04% 0.10% C276 N/A C276 2xFLUKE-700P30 5000 psi / 0.1 34 M Pa / 0.001 0.04% 0.10% C276 N/A C276 2xFLUKE-700P31 10000 psi / 1 69 M Pa / 0.007 0.04% 0.10% C276 N/A C276 1.5x

Documentation of resultsThe scheduling of calibration, creation of procedures anddocumentation of your calibration results are facilitated by anumber of instrumentation management software packages:

• Fluke DPC/TRACK™

• Cal Station and Base Station

• ™ InstruMint and DocuMint

•

• ™ QM6 Quality Manager Calibration Software

DPC/TRACK is a trademark of Fluke Corporation. Cornerstone is a trademark of AppliedSystem Technologies. InstruMint and DocuMint are trademarks of Honeywell. Sand Coveis a trademark of Digital Products Limited. QM6 is a trademark of Oy Beamex Ab.

Sand Cove™

Instrumentation Manager

700 Series Pressure Modules Fluke Corporation 4

Sourcing pressureTo calibrate an instrument with pressure input, pres-sure from an external source (such as a hand-heldpump) is applied. Prompts on the display indicatewhen to increase or decrease the input pressure,and when the specified test points are achieved.

Hand Pump

+

Pressure Module

Red

Black

702 DOCUMENTING PROCESS CALIBRATOR

MEASSOURCE SETUPmA

V VHz

TCRTD

7 8 9

4 5 6

1 2 3

0 . ENTER

CLEAR(ZERO)

RANGE

VRTD

MEASSOURCE

mA mA

RTD

V

300VMAX

30V MAXTC

702 DOCUMENTING PROCESS CALIBRATOR

7 8 9

4 5 6

1 2 3

0 .

V

MEASSOURCE SETUPmA

VHz

TCRTD

CLEAR(ZERO) RANGE

ENTER

VRTD

MEASSOURCE

mA mA

RTD

V

300VMAX

30V MAXTC

702 DOCUMENTING PROCESS CALIBRATOR

IsolationValve

PressureModule

HandPump

PressureModule

701 DOCUMENTING PROCESS CALIBRATOR

MEASSOURCE SETUPmA

V VHz

TCRTD

7 8 9

4 5 6

1 2 3

0 . ENTER

CLEAR(ZERO)

RANGE

VRTD

MEASSOURCE

mA mA

RTD

V

300VMAX

30V MAXTC

Measuring pressureTo measure pressure, the appropriate pressure mod-ule for the pressure to be tested is attached to thecalibrator. The measured pressure can be displayedin psi, mmHg, inHg, inH20, ftH20, bar, kPa or mH20.

Figure 3.Typical

configurationfor measuring

pressure.

Figure 4.Typical

configurationfor sourcing

pressure.

Figure 5. Typicalconfiguration forusing a pressure

module tocalibrate a P to I

device.

P to I device calibrationThe P to I device is used to convert pneumatic analogloop control signals of 3 psi to 15 psi to electricalloop analog control signals of 4 mA to 20 mA.

Typical Applications

702 DOCUMENTING PROCESS CALIBRATOR

7 8 9

4 5 6

1 2 3

0 .

V

MEASSOURCE SETUPmA

VHz

TCRTD

CLEAR(ZERO) RANGE

ENTER

VRTD

MEASSOURCE

mA mA

RTD

V

300VMAX

30V MAXTC

702 DOCUMENTING PROCESS CALIBRATOR

HL

DifferentialModule

+IsolationValve

+

PressureModule

702 DOCUMENTING PROCESS CALIBRATOR

MEASSOURCE SETUPmA

V VHz

TCRTD

7 8 9

4 5 6

1 2 3

0 . ENTER

CLEAR(ZERO)

RANGE

VRTD

MEASSOURCE

mA mA

RTD

V

300VMAX

30V MAXTC

Red

Black

Differential measurementsDifferential pressure modules are useful in awide variety of applications, e.g., measuringthe fluid level in a tank or calibrating adifferential pressure transmitter.

Figure 7.Typicalconfigurationfor differentialpressuremeasurement.

I to P device calibrationThe I to P device is used to convert electricalloop analog control of 4 mA to 20 mA topneumatic analog loop control, generally3 psi to 15 psi.

Figure 6.Typicalconfigurationfor using apressuremodule tocalibrate anI to P device.

Terminology

Absolute pressure—absolutepressure measurements arereferenced to zero pressure,(a perfect vacuum.)

Absolute pressuretransducer—a transducer thathas an internal referencechamber sealed at or close tozero pressure (full vacuum)when exposed to atmospherea reading of approximately14.7 psi results.

Boyle’s Law—the volume of agas is inversely proportional tothe pressure of the gas at con-stant temperature: V=1/P.

Common mode pressure—theunderlying common pressure(or static pressure) within a sys-tem from which a differentialmeasurement is being made.

D/P: Differential pressure,(pronounced DP)—other namesused to mean the same thing ared/p cell, d/p transmitter and ∆Ptransmitter (where ∆ is delta ordifferential). This is the mostcommon type of transmitter usedin most process industries. It canbe used to measure level, flow,pressure, differential pressure,and density or specific gravity.With some modifications, it canmeasure such things as tem-perature and oxygen purity. Thed/p transmitter can be pneu-matic, electromechanical, orsolid state. It can also be a smarttransmitter. A typical large pro-cess plant can have hundreds orthousands of d/p transmitters inservice.

PSI—pounds per square inch(same as psig).

PSIA—pounds per square inchabsolute.

PSID—pounds per square inchdifferential.

PSIG—pounds per square inchgage (same as psi).

Square root extractor—aninstrument or software programthat takes the square root ofinput and puts the result on itsoutput. Square root extraction isneeded to linearize many flowsignals. Example: orifice plates,venturis, target flow meters, andpitot tubes all require thetransmitter’s output signal to belinearized. Mag flow meters,turbine flow meters, Dopplerflow meters, and vortex shed-ding flow meters don’t requiresquare root extraction.

Static pressure—the zero-veloc-ity pressure at any arbitrarypoint within a system.

Wet/dry differential—a differ-ential pressure transducer ortransmitter that uses a metaldiaphragm at the wet portwhere fluids can be applied, andno diaphragm at the dry port.The dry port exposes the sensormaterial to the medium, so onlyclean dry gas can be applied tothis port.

Wetted parts—the diaphragmand pressure port material thatcomes in direct contact with themedium (gas, liquid).

Gage pressure—the pressurerelative to atmospheric pressure.Gage pressure = absolute pres-sure minus one atmosphere.

Gage pressure transducer—a transducer that measures pres-sure relative to atmosphericpressure.

Ideal Gas Law—combiningBoyle’s Law and Charles’ Law,results in the Ideal Gas Law:PV=nrT, where nr is constant fora particular gas analogous to thenumber of molecules and therelative size of the molecule.

I/P (I to P)—a current to pres-sure transmitter. A common in-strument in modern industrialplants. A typical large paper millor refinery could have 5,000 I/Psin use.

Line pressure—the maximumpressure in the pressure vesselor pipe for differential pressuremeasurement.

Orifice plate—a very low costand common primary sensingelement (PSE) for measuringflow. It must be used in conjunc-tion with a d/p cell. It creates aventuri and a resulting P isdeveloped across the platewhose square root is propor-tional to flow.

P/I (P to I)—a pressure to cur-rent transducer.

Pneumatic relay—refers to apneumatic instrument that per-forms a function to its input andprovides the result on its output(Example: square root extractor,adder, etc.).

700 Series Pressure Modules Fluke Corporation 5

Fluke-700 PCKCalibration KitThe Fluke 700PCK Pressure Cali-bration Kit makes it possible tocalibrate your pressure modulesat your facility using your ownprecision pressure standards.The kit consists of a power sup-ply, an interface adapter, appro-priate cables, and Fluke 700PCPressure Module Calibration soft-ware. When installed on your PC,the Windows®-based softwareeasily steps you through an as-found verification, a calibrationadjustment, and an as-left verifi-cation. Calibration data is cap-tured for import to your database.A 386 or better PC, runningWindows 3.1, is required, alongwith a precision pressure stan-dard with an uncertainty of lessthan 1/4 that of the pressure mod-ule being verified.

Fluke CorporationPO Box 9090, Everett, WA USA 98206

Fluke Europe B.V.PO Box 1186, 5602 BDEindhoven, The Netherlands

For more information call:U.S.A. (800) 443-5853 orFax (425) 356-5116Europe/M-East (31 40) 2 678 200 orFax (31 40) 2 678 222Canada (905) 890-7600 orFax (905) 890-6866Other countries (425) 356-5500

©1998 Fluke Corporation. All rights reserved.Printed in U.S.A. 1/98 B0300UEN Rev C

Printed on recycled paper.

12345678

PressureCalibrator

InterfaceUnit

PC Serial Port

Line Power

PressureModule

Figure 8. Calibration kit configuration.

CERT IFIED TO MEET ISO

9001

QUALIT

Y MANAGEMENT SYSTEM

ISO 9001

Fluke-700 PMPPressure PumpThis hand operated pressurepump can provide pressures up toapproximately 150 psi (1000 kPa)for calibration and troubleshoot-ing of pressure instrumentation.

Figure 9. Pressure pump

Fluke. Keeping your worldup and running.