Calibration PT Honeywell Chapter 7 InstrumentationELC-213Today Presentation by Clifford T. Johnson,...

Calibration PTHoneywell Chapter 7

Calibration PTHoneywell Chapter 7

Instrumentation ELC-213Today

Presentation by Clifford T. Johnson, PE, Control Systems Engineer

Honeywell Primer Auxiliaries

What is Calibration?What is Calibration?

Instrumentation ELC-213Calibration

WHAT IS CALIBRATION?There are as many definitions of calibration as there

are methods.According to ISA’s The Automation, Systems, and Instrumentation Dictionary,the word calibration is defined as “a test during which known values of

measurand are applied to the transducer and corresponding output readings are recorded under specified conditions.” The definition includes the

capability to adjust the instrument to zero and to set the desired span.

What are the CharacteristicsWhat are the

Characteristics

Instrumentation ELC-213

WHAT ARE THE CHARACTERISTICS OF ACALIBRATION?

•Calibration Tolerance: Every calibration should be performed to a specified tolerance. The terms tolerance and accuracy are often used incorrectly. In ISA’s The Automation, Systems, and Instrumentation Dictionary, the definitions for each are as follows:•Accuracy: The ratio of the error to the full scale output or the ratio of the error to the output, expressed in percent span or percent reading, respectively.•Tolerance: Permissible deviation from a specified value; may be expressed in measurement units, percent of span, or percent of reading.Calibration

Why is it requiredWhy is it required


WHY IS CALIBRATION REQUIRED?Calibration is required for a new instrument because we want to make sure the instrument is providing accurate indication or output signal when it is installed.

Instrument error can occur due to a variety of factors: drift, environment, electrical supply, addition of components to the output loop, process changes, etc.

Calibration is performed by applying a known signal to the instrument under test.

An error is the algebraic difference between the indication and the actual value of the measured variable.

Calibration

Who performs calibrationWho performs calibration


WHO PERFORMS CALIBRATIONS? – THECONTROL SYSTEM TECHNICIAN

A (CST) is a skilled craftsperson who knows pneumatic, mechanical, and electrical

instrumentation. He or she understands process control loops and process control systems, including

those that are computer-based..

CST is a certification by the ISA (International Society for Automation). I am a certified instructor for the ISA and can proctor the test here at CPCC. Contact me for further information. NOTE:

there is a charge for the Certification Test

Calibration

The TechThe Tech


CHARACTERISTICS OF A CONTROL SYSTEM

TECHNICIAN

•Honesty and Integrity•Attention to Detail•Excellent Documentation Practices•Understanding of Processes

•Honesty and Integrity•Attention to Detail•Excellent Documentation Practices•Understanding of Processes

Calibration

Loop CalibrationLoop Calibration


LOOP CALIBRATION VS. INDIVIDUALINSTRUMENT CALIBRATION

An individual instrument calibration is performed only onone instrument. The input and output are disconnected. A known

sourceis applied to the input, and the output is measured at various data

pointsthroughout the calibration range. The instrument is adjusted, if

necessary,and calibration is checked and/or corrected

DISADVANTAGES OF INDIVIDUALCALIBRATION

ADVANTAGES OF INDIVIDUALCALIBRATION

1. Entire loop is not verified withintolerance2. Mistakes on re-connect3. Less efficient use of time to do onecalibration for each loop instrument asopposed to one calibration for the loop

1. Correct instrument will be adjusted2. More compatible with multifunctioncalibrators

Calibration

Calibration Form for PTCalibration Form for PT

Form ELC-213

1/11/2012

Owner:

Tag: System ID:

Description: Plant Location

Manufacture: Calib Location

Model No.: Classification

Instrument Range LRV / URV / Units 0 100 in wtrCalibration Range LRV / URV / Units 0 100 in wtr

Accuracy Full Scale/Rg 0.1% F.S. Opt Fail position

Elevation Suppression NA NA

Output Signal Electrical mA Pneumatic

% Calib Signal 10% 25 50 75

Calib Signal EU 5.6mA 8mA 12mA 16mA

Instr Meas/Out

Instr Required 4 In wtr 10 in wtr 20 in wtr 30 in wtr

Instr as Found

Instr as Left

As Left error

May be used to calibrate both analog Transmitters and Transducers

NA

NA

GP

Calibration data: Suggest using 10, 25, 50, 75, 90 % for 5 points

90%

18.4mA%

36 in water

Rosemount

1151

INSTRUMENT CALIBRATION SHEET

Device to be Calibrated

LT-102

d/p transmitter

CPCC

Flow Lab

Charlotte, NC

ATC Lab 3rd Flr

Calibration

Use your Tag

40

Honeywell Chapter 7- AuxiliariesHoneywell Chapter 7- Auxiliaries

Instrumentation ELC-213Honeywell

Record Rate of FlowRecord Rate of Flow


Total FlowTotal Flow


Linearization of flow rateLinearization of flow rate


Why a Square Root Extractor is required?Because flow measured

by dp is not linear.

The formula describing this relationship is as

follows:Q = K ••P

Q = The quantity of flowK = A calibration constant that depends on the size of the restriction when compared to the inner pipe diameter, the maximum flow rate, and other non-changing parameters•P = The differential pressure between the high pressure upstream side and the low pressure downstream side of the restriction.

Honeywell

Square Root ExtractorSquare Root Extractor


Mass Flow LoopMass Flow Loop


Adder SubtractorAdder Subtractor


Adder Subtractor LoopAdder Subtractor Loop


Calibration of final control

devices:Valves,motors,Drives,

Dampers,

Calibration of final control

devices:Valves,motors,Drives,

Dampers,


Control valve

Assignment ELC-213

Homework ASSIGNMENT Web LinkHomework ASSIGNMENT Web LinkSend me a link to Calibration instructions for a Pressure Transmitter, The Download the calibration form for next

weeks lab

Email Ex:Email Ex: Johnson-PT Cal- Johnson-PT Cal-AD

All Emails Subjects and File names must haveAll Emails Subjects and File names must have

Turn in Calibration sheet with 2 Students Names near bottomTurn in Calibration sheet with 2 Students Names near bottom

You will lose 1-3 points for incorrect subject

Subjects

SubjectSubject::Your last Name-Subject-Assignment Date (AD)

Cal of LTdp ELC-213

The EndThe End

End

This is what you are to calibrate, a Rosemount 1151 dp transmitter previously used to

measure the level in the receiver tank on the Flow Lab

Calibration PT Honeywell Chapter 7 InstrumentationELC-213Today Presentation by Clifford T. Johnson,...

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