Positioner input feedback
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I would like to ask the experts: the electrical signal for adjusting a butterfly valve is 4–20 milliamps. When 20 milliamps are applied, the valve should be fully open, as indicated by 20 milliamps. Currently, the valve is open at 60%, which corresponds to 12 milliamps. What should I do?
Typically, control valves are equipped with potentiometers for adjusting the range and zero point, and adjustments are made to these potentiometers until the desired settings are achieved.
If your control valve outputs 20MA at 100% and 4MA at 0%, then the process should be linear, with little variation; it’s better to do more tuning
Your question doesn’t seem to be clearly described. 1, “When 20 milliamps is entered, it should display 20 milliamps when it’s at full capacity, right?” ”It shows 20ma; it displays 20ma there. Is it 20ma at the input or 20ma at the output? I didn’t understand what you said. 2\"The valve is currently open at 60%, with a current of 12 milliamps. What should be done? With an opening degree of 60%, is this 12 mA the feedback current or the input current?\" Can I understand that you supplied a signal of 20 ma to the locator, resulting in an opening degree of only 60% for the locator, with a feedback signal of 12 ma? If it’s as I understand it, I’m not sure which company’s locator it is. Find the manual and perform self-tuning once!
When it’s at 4 milliamps, the zero point isn’t set correctly; adjusting it again will fix it
Positioners are all capable of adjusting their opening degree
This valve positioner should not have been initialized at the time of manufacture. I don’t know; it’s a valve positioner from that manufacturer, so it’s best for you to have the manufacturer adjust it.
If it’s a 12 milliampere signal from the positioner input method, and the valve opening degree as well as the valve position feedback signals indicate 60%, then this is due to improper settings for parameters such as the actuator and air supply pressure during the configuration of the positioner. Make the necessary adjustments and conduct another automatic check; everything should be fine then