USE “SEARCH” TAB ON the top right side FOR ALL INSTRUMENTATION RELATED TOPICS
1.Isolate the Pressure Transmitter from the Process.
2.Depressurize the process by slowly open the vent plug and the vent valve.
3.Note down the transmitter output from DMM / HART Communicator. Ensure the transmitter output is 4 mA.
4.Connect Pressure source calibrator to the transmitter as shown beloworor
5.Ensure there is no leak.
6.Apply pressure as per range of transmitter in steps of 25%, 50%, 75% and 100% increasing and decreasing steps
7.Note down transmitter output for each step
8.Calculate the error and compare with allowable limit.
9.If it is within limit then the previous calibration is ok, then go-to step 15. Otherwise continue with step 12
10.If the error calculated is not within the limit then calibration is required.
11.Apply zero pressure and adjust zero of the transmitter
12.Apply 100% pressure and adjust span of the transmitter
13.Repeat the steps 12 and 13 until get the desired result
14.Repeat the steps 7 and 8 and ensure the readings are within limit
15.In case of SMART Transmitter Repeat steps 8 through 16 and follow through the HART Communicator Menu for lower range value trim and upper range value trim. Basic Set up – Calibration – Zero Trim/Sensor Trim —Lower/Upper range value trim.
16.Ensure for the correct indications in HMI at Control Room
17.Depressurize and remove the pressure source
18.Restore the process connection; Ensure all the vent & drain plugs / valves are fully tightened.
19.Take the transmitter on line. Ensure there is no leak
The calibration pressure percentage error check list is as shown below:
To learn more about Instrumentation and Control, purchase your copy now