Steps to calibrate control valves

The basic procedure for control valves calibration step to step.

You will need the following information:

Data sheet

You will need the following equipment:

Hart Communicator (Emerson 375 or 475 etc…)

What you need to know to properly make the calibration:

Valves can be either air to open or air to close. With one you start with the valve closed and the other with the valve open. The procedure is the same for both types of valves.

Steps to calibrate control valves:

  1. Ensure that the control valve is isolated from the process if working on live system or newly installed system. “IMPORTANT USE LOCK OUT TAG OUT Procedures”

  2. Make sure the controller is in manual mode for the control loop.

  3. Verify steps 1 and 2 are done a second time to insure safety of yourself and others that may not be involved in the process being worked on.

  4. Hook up the Heart communicator and verify the parameters by referencing data sheet with tag number of the instrument to be calibrated.

  5. Change the control valve from normal to setup mode.

  6. Select auto find stop (This should require 1 to 5 minutes depending on equipment used and being be calibrated.

  7. If control valve shows “Full Open more then 100% - Select open adjustment and input new number that is associated with this per data sheet and or per engineered calculation.

  8. Set an auto calculation (this should require one to five minutes).

  9. Verify the linearity. This can be done by increasing and decreasing the travel by quarter percentages (0%, 25% to 100%) and (100%, 75% to 0%).

  10. To complete the process and verify that the controller and the control valve are working properly put the loop back into normal mode and test for correct calibration.

  11. Document all work having been done on standard calibration form and properly log in system used and update any job books required by company.

The information above is just one method and you should follow the recommendations from the manufacture and your company procedures if they are available.

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