How To Calibrate Control Valve Positioner.

How To Calibrate Control Valve Positioner./ Procedure for Control Valve Positioner Calibration.

Equipments required:-

1. Positioner.
2. Control valve.
3. Pressure source.

The procedure for Control Valve positioner Calibration:-

1. Zero adjustments are done at the nozzle
2.  Span adjustment is done by moving flapper assembly (follower assembly) along the summing beam
3. The air supply to the positioner is 20 psi.
4. To calibrate move the flapper assembly to midrange of direct side or about no.6
5. Increase the input signal to 3 psi.
6. Adjust the nozzle in or out slowly to make the output gauge output 0 psi.
7. Increase the input pressure to 15 psi.
8. If the output saturates too soon (at the output gauge) before giving 15psi move the flapper assembly to a smaller number in the summing beam. 
9. If the output saturates too late or above 15 psi move flapper assembly to a larger number at the summing beam.
10. Every time when you move the flapper assembly reset the nozzle to zero also.