Calibration of pneumatic diaphragm control valves with valve positioners
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May I ask how calibration is carried out for pneumatic diaphragm control valves with valve positioners in a laboratory? Is it done by calibrating the valve alone first, then installing the positioner, and finally calibrating both the valve and the positioner together?
Do you focus on the valve or on the condition of the positioner?
There is no need for individual calibration of the valve; it is sufficient to calibrate the actuator together with the valve.
You still need to use a single-stage valve first; if the valve core isn’t in place, it’s useless to install a positioner for calibration. :)
After the locator is installed, simply verify it at 0%, 25%, 50%, 75%, and 100% respectively.
What was said on the 4th floor is correct; the control valve itself should be checked first, and only after it’s fine should the positioner be checked.
Just 3 points are enough: 0%, 50%, 100%
The valve should be calibrated first, followed by joint calibration with the positioner; pay attention to the valve dead zone
A joint school will work; set the schedule at 50% for now and then verify it