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Everyone, are the forward and reverse output settings of the two three-way control valves used for natural gas hydrogen production in the refining unit set the same in the DCS?
This post was last edited by *efeinihao on 2015-12-27 11:23. Valve positioners have forward and reverse actions, valves have forward and reverse actions, and PID controllers also have forward and reverse actions. It must be different. Under normal circumstances, the positioner operates in a direct manner; whether the valve operates in forward or reverse mode is determined by the process requirements and is fixed. The forward and reverse actions of a PID are determined by the process requirements – for example, whether it is to stabilize the pressure before the valve or the pressure after the valve; this determines whether forward or reverse action is used.