Calibration How to Instrumentation

Calibration Procedure : Control Valve

How to calibrate control valve?

Required Material:
1) Data sheet
2) Hart Communicator
Step wise Procedure: 
*Ask panel man to put the controller in manual mode for control loop 
*Isolate the Control valve from the process.
WARNING – The Isolation of control valve from the process shall be done by field operator. Careful step shall be done to ensure no upset to the operation.
*Hook up HART Communicator and verify some parameters by refer to data sheet such as Tag Number, OP and etc. 
*Change from normal mode to setup mode
*Select auto find stop (wait some minute)
*If full open is more than 100% select open adjustment and put new number as per calculation
*Make an auto calibration ( wait some minute)
*Verify the linearity by increasing and decreasing the travel (0%,25%,50%,75%,100%,75%,50%,25% and 0%of range)
*After completion of the job ask panel operator to put loops back in normal mode 
*Fill the calibration form and file it for future reference.
Example calculation
A: Max travel from stem   70mm
B: Scale plate   50mm
New open adjustment should be (50/70) X 100 = 71.48%

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1 comment

AcuteSoft December 10, 2014 at 3:15 pm

If the control valve we are using is SMART valve then we can use HART communicator for calibrating. Provide the supply pressure according to the valve name plate then use HART communicator and give 0% 25% 50% 75% & 100%. Now check the traveling of valve.

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