calibration pt honeywell chapter 7 instrumentationelc-213today presentation by clifford t. johnson,...
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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
Instrumentation ELC-213
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
Instrumentation ELC-213
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
Instrumentation ELC-213
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
Instrumentation ELC-213
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
Instrumentation ELC-213Honeywell
Total FlowTotal Flow
Instrumentation ELC-213Honeywell
Linearization of flow rateLinearization of flow rate
Instrumentation ELC-213
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
Instrumentation ELC-213Honeywell
Mass Flow LoopMass Flow Loop
Instrumentation ELC-213Honeywell
Adder SubtractorAdder Subtractor
Instrumentation ELC-213Honeywell
Adder Subtractor LoopAdder Subtractor Loop
Instrumentation ELC-213Honeywell
Calibration of final control
devices:Valves,motors,Drives,
Dampers,
Calibration of final control
devices:Valves,motors,Drives,
Dampers,
Instrumentation ELC-213Honeywell
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