calibration of i/p (current/pressure) honeywell chapter 8
DESCRIPTION
Calibration of I/P (current/Pressure) Honeywell Chapter 8. Honeywell Primer: Noise Environments. Presentation by Clifford T. Johnson, PE, Control Systems Engineer. Today. Instrumentation. ELC-213. Wire Function. wiring. Honeywell. ELC-213. Chapter AC Load Suppression. Suppression. - PowerPoint PPT PresentationTRANSCRIPT
Calibration of I/P (current/Pressure) Honeywell Chapter 8
Calibration of I/P (current/Pressure) Honeywell Chapter 8
Instrumentation ELC-213Today
Presentation by Clifford T. Johnson, PE, Control Systems Engineer
Honeywell Primer: Noise Environments
Honeywell ELC-213
Wire FunctionWire Function
wiring
Honeywell ELC-213
Chapter AC Load Suppression Chapter AC Load Suppression
Suppression
Honeywell ELC-213
AC Contact suppressionAC Contact suppression
Suppression
Honeywell ELC-213
DC SuppressionDC Suppression
Suppression
noise can enter equipment bynoise can enter equipment by
1. Capacitive (or electrostatic)2. Inductive (or magnetic)3. Impedance.
HoneywellNoise ELC-213
Signal cable should always be separated for power cableNever run in the same conduit and
Use dividers in cable tray
Honeywell ELC-213
Prevent Electrical NoisePrevent Electrical Noise
Suppression
There are three ways to prevent electrical noise from interfering with the operation of the electronic digital equipment. • Built-in noise rejection
• Separation of signal and power lines• Noise suppression at source
Ever wonder why Ethernet Cat5 cable is NOT shielded?
ANS: It relies on the BALANCED LINE twisted pair design and differential signaling for noise rejection.
Transducer ELC-213
GroundingGrounding
I/P
Never Grd Shield in the fieldBend back and tape
Operation ELC-213
I/P Principle of operation I/P Principle of operation
I/P
Operation ELC-213
I/P Principle of operation I/P Principle of operation
I/P
Accuracy ELC-213
I/P AccuracyI/P Accuracy
I/P
The accuracy of an I/P transducer is defined in several ways. The most important measure is linearity. This is measured as a percent of span. In this case, the span is 12 (15 minus 3) psig. So if the linearity of the I/P was 1% of span, then the possible variation could be 1% of 12 or 0.12 psig. So in this case, the expected output with a 12mA signal. The output should be 9 psig but could be between 8.88 – 9.12 psig. Linearity can be as low as 0.1% and as high as 3% of span, depending on the construction and cost of the I/P.
Accuracy ELC-213
I/P Repeatability & HysteresisisI/P Repeatability & Hysteresisis
I/P
Repeatability measures the ability of the unit to come back to the same pressure setting after resetting the input signal.
Hysteresisis is the variation in the output pressure achieved when increasing the input signal versus decreasing the input signal. For example, when going from 4 mA to 12mA a certain pressure will be attained. A different output pressure will be achieved when going from 20mA to 12 mA.
Summary ELC-213
Accuracies are additiveAccuracies are additive
Accuracy
Unless specified, these three measurements can be additive. Thus a 3-15 psig unit with +/- 1% linearity, +/- 1% Hysteresisis,+/- 1% repeatability, could be off by +/- 3%, or +/- .36 psig 3% span
Calibration ELC-213
I/P Zero CalibrationI/P Zero Calibration
I/P
Always check the zero setting first. Apply the minimum electrical signal and observe the output pressure. It should be the minimum value of the pressure range. For example, a 4-20mA, 3-15 psig unit should give a 3 psig output at 4mA. If the output is not 3, turn the zero screw until the output pressure reaches 3. The screw may be turned in different directions depending on whether the unit is an I/P or E/P.
Calibration ELC-213
I/P Span CalibrationI/P Span Calibration
I/P
Once the zero has been set, apply the maximum electrical signal, in this case, 20mA. The output should be close to the desired output, in this case 15 psig. Turn the span screw in the appropriate direction to achieve the desired pressure. Some I/P’s have interactive zero and span. In that case, after adjusting the span, the zero will need to be adjusted again, especially if the span was adjusted by a large amount.
Supply ELC-213
I/P Media SupplyI/P Media Supply
I/P
The most common media for I/P’s is compressed air. They can also be used with many other inert gases. However, due to the constant consumption of the media, one must consider the environmental impact of the release of gas into the environment. You should definitely check the specifications before using the I/P with media other than compressed air.
Cal Form ELC-213
Calibration formCalibration form
I/P
Owner:
Tag: System ID:
Description: Plant Location
Manufacture: Calib Location
Model No.: Classification
Instrument Range LRV / URV / Units 0 18 psigCalibration Range LRV / URV / Units 3 15 psig
Accuracy Full Scale/Rg +/- 0.3%. Opt Fail position
Elevation Suppression NA NA
Output Signal Electrical na Pneumatic
% Calib Signal 0% 25% 50% 75%
Calib Signal EU 4 mA 8 mA 12 mA 16 mA
Instr Meas/Out
Instr Required 3 psig 6 psig 9 psig 12 psig
Instr as Found
Instr as Left
As Left error
NA
3-15 psig
20 mA
GP
Calibration data: Suggest using 10, 25, 50, 75, 90 % for 5 points
100%
15 psig
M-Systems
HVPN-2A3
Device to be Calibrated
LY-102
I/P Transducer
CPCC
Cal Lab
Charlotte, NC
ATC Lab
Use your Tag
Analyzer ELC-213
Calibration of AnalyzersCalibration of Analyzers
pH
pH is one of the most difficult
Analyzers to calibrate
because the measurement
is log
Assignment ELC-213
Homework ASSIGNMENT Web LinkHomework ASSIGNMENT Web LinkFind instructions on Internet for PID Control Modes.
email web page LINK only to me by Sunday
Email Ex:Email Ex: Johnson-PID Modes- Johnson-PID Modes-AD
All Emails Subjects and File names must haveAll Emails Subjects and File names must have
You will lose 1-3 points for incorrect subject
Subjects
SubjectSubject::Your last Name-Subject-Assignment Date (AD)
Calibration ELC-213
The EndThe End
End
M-Systems I/P you will
be calibrating