Issues regarding the locator input signal
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For temperature control of the reactor, there are 2 thermal valves: one is used for the material flow and the other for steam. 1 cold valve for cooling water flow. What should be the input signals for those 3 control valve positioners? I encountered a hot valve and a cold valve before; the technician said that proportional control could be used, with the controller’s input signal ranging from 4-12 MA to 12-20 MA. So now there are 2 thermal valves; what should the input signal be?
According to the actual requirements of the operating conditions, one valve operates across its full stroke, while the other two do so in divided steps.
Do you still need to use stepwise adjustment? I suggest you first explain your current control scheme. Could proportional control of the material and cooling water be considered? If the temperature of the cooling water changes little while the temperature of the material changes significantly, then the temperature of the material could be used as a feedforward signal for steam control, thereby implementing such a control scheme
I don’t quite understand what the moderator is referring to. I’ll show everyone screenshots of the manufacturing process; please help me analyze it as well. Thank you all
There should be a detailed description of the control scheme; flowcharts alone are not sufficient to explain it clearly.
All controls are implemented within control schemes such as PID; its output can be used to control valves. Features like range modulation (4-8, 8-20, etc.) can all be converted into standard 4-20 signals that are sent to the actuator.
The reactor temperature can be used； Feed flow rate ； The feed flow valve forms a cascade control system for the temperature of the reactor ； Steam inlet valve ； The inlet circulating water valve enables stepwise regulation.
Anyway, a certain control scheme can achieve the goal; analyze it more carefully