Mechanical valve positioner
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Most of the valve positioners used in our company are intelligent valve positioners; mechanical valve positioners are also available, but we have not conducted any in-depth research on them. May I ask which expert has detailed experience in debugging mechanical valve positioners? How to adjust the 4~20mA signal for various adjustment positions of the valve at full open and full closed states?
Reply to 1# Lingfei: 1. After the valve positioner is installed, connect the instrument air supply and check whether the air path is unobstructed, for any signs of leakage, and whether the pressure output by the filter regulator meets the requirements. 2. If it is a pneumatically operated valve, an input of 4 mA corresponds to the valve being in the fully closed position; if this is not the case, adjust the zero point of the positioner so that the valve is fully closed. Enter 20mA for the valve to be fully open; if this is not correct, adjust the setpoint of the positioner for a fully open valve. 3. There should be no dead zone at the zero point or within the range. 4. Then, verify repeatedly at the scale levels of 0%, 20%, 40%, 60%, 80%, and 100% until the requirements are met.