This procedure defines how to carry out the Calibration of Pressure Transmitter

1. I&C Channel
www.iandc-channel.com
Pressure Transmitter Calibration Procedure
Oil & Gas industry
1. DEFINITIONS / REFERENCES
DCS Distributed Control System
IPF Instrument Protective Function
PTW Permit to Work
HSE Health, Safety & Environment
H2S Hydrogen Disulphide
PPE Personal Protective Equipment
ARA Activity Risk Assessment
MOS Maintenance Override Switch
PT Pressure Transmitter
HP High Pressure
LP Low Pressure
2. PRECAUTIONS
Follow PTW system.
Use proper PPE and follow HSE requirement as per company policy.
If PT is connected to Trip Loop Override IPF signal during calibration of PT by following IPF
override (MOS or Forcing) procedure.
If PT is connected to Control Loop Coordinate with control room operator to put the controller in
manual mode.
3. TEST EQUIPMENT
Multi meter (Certified: Calibration date not expired)

2. I&C Channel
www.iandc-channel.com
Pressure calibrator (Certified)
Hart communicator

3. I&C Channel
www.iandc-channel.com
4. PROCEDURE
Step
No
.
Sequential Action Remarks
1
Refer to the related documents such as P&ID, ILD, data
sheet, C&E matrix if required and ARA prior to go to the field.
- P&ID to locate the PT.
- ILD to follow the loop.
- Data sheet to confirm range.
- C&E matrix to know the actions.
- ARA for risk assessment.
2 Validate the permit & Take necessary precautions. - Get field operator approval for transmitter.
3
Use proper access and do visual check to ensure
correct tagging, damages, terminals corrosion,
connections tightening, Earth leak and cleanliness.
4
Check for leaks from manifold and tubing and attend
if any.
Use leak tester to check for hydrocarbon
leaks.
5
Connect HART communicator and multi meter to the
transmitter and note the output reading.
As found :
Pressure= Bar & Current = mA
6
- Close isolation valves.
- Open drain plugs to depressurize the process fluid
from the transmitter safely and slowly keeping in
mind the process nature and wind direction.
1. If no drain plugs:
- Close isolation valves
- Open the equalizing valve.
- Open the vent.
2. If isolation valve is passing, inform the
operator and cancel the task.
3. Monitor your H2S detector.
7 Close the equalizing valve if it is open. Keep the vent open to atmosphere.
8
With a certified pressure calibrator inject at HP side
what is equal to low range value (LRV) and note the
transmitter zero as found:
0%:
Pressure= Bar & Current = mA
If different of 4 mA trim (adjust) the zero by HART
communicator.
- Refer to transmitter vendor manual to locate
zero trim in the menu.
- Note down reading in the attached calibration
record form.
9
With a certified pressure calibrator inject at HP side
what is equal to high range value (URV) and note the
transmitter full scale as found:
100%:
Pressure= Bar & Current = mA
If different of 20 mA adjust the span by HART
communicator.
- Refer to transmitter vendor manual to locate
span trim in the menu.
- Note down reading in the attached calibration
record form.

4. I&C Channel
www.iandc-channel.com
10
Repeat (8) and (9) steps till zero and span calibration
is achieved.
11
Check the intermediate calibration points: 25%, 50%
and 75% and confirm the reading and alarm actuation
and reporting with panel operator in DCS.
- Refer to transmitter vendor manual for
alignment if any no-linearity error is noticed.
- Note down reading in the attached calibration
record form.
12
Remove all test equipment and tighten connections
and fittings properly.
Confirm no leak with leak tester.
13
Line up the transmitter:
- Close drain plugs
- Confirm transmitter reading is normal.
Note the indication as left :
Pressure= Bar & Current = mA
If no drain plugs
- Close the vent valve.
- Open the equalizer.
- Open HP&LP isolation valves.
- Close the equalizer.
14 Do the housekeeping in work place.
15
Complete IPF form in control room to normalize the
override.
16 Close the work permit.

5. I&C Channel
www.iandc-channel.com
5. CALIBRATION RECORD FORM
Location: Date :
Tag No
. : Range :
Test equipment
Pressure Calibrator Multi meter
Serial No.
Calibration expiry date
%
Theoretical Actual output
Error % Remarks
bar mA
As found
(mA)
As left
(mA)
0
25
50
75
100
100
75
50
25
0
Error tolerance < + or - 0.25%span
Calibrated By : Checked / Witnessed by: