Problems with valve position control of remote control valves
Thread Content
I heard that the remote control valve allows the opening degree to be set in the control room, but generally, there is no indicator for the opening degree in the control room unless there are special requirements; as a result, the set opening degree may differ from the actual operation on site. I don’t understand this statement; please, those who are good at self-control can help clarify it for me! Thank you
This post was last edited by ylb913 on 2018-6-14 at 22:10. There is no display in the room for feedback on the opening degree of the pneumatic control valve. It relies on controlling parameters such as flow rate, pressure, liquid level, and temperature; when this control is not adequate, the air pressure keeps changing, generating signals to increase or decrease the valve opening further.
For remote control valves, whether pneumatic or electric, it is possible to set the opening degree from the control room. In the case of pneumatic valves equipped with mechanical electrical valve positioners, the problems you mentioned often occur. However, with intelligent valve positioners or electric actuators that include valve position feedback mechanisms, it is rare for there to be a discrepancy between the set value and the actual feedback; such devices will automatically make corrections. But if it is necessary to display the valve position feedback signal on a higher-level computer, then a communication signal card or an additional feedback signal cable is required to achieve this
What’s not quite clear to me is whether the valve position should be displayed by default
No, many factories take investment considerations into account. After all, the feedback signal requires an AI channel and a signal cable; do you realize that the feedback signal isn’t really necessary in practical use?