PID regulator
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What does it mean to communicate with the DCS to set the PID controller of the control valve to manual mode and the output value to 0?
Prevent cascading recovery; excessive valve variation
It’s not about what the purpose of doing this is; I can’t understand the meaning of that sentence. What does it mean to output 0?
Is it a foreign product? Translate it like this. My understanding is that in DCS, the PID regulator is set to manual mode, and then it is adjusted manually so that the PID output is 0.
None of you understand what I mean. You repeated what I said; what I want to know is what this phrase means – when the regulator output is 0, what does that specifically mean? Does it mean that the valve is closed?
There is a difference between expression and understanding; it’s sufficient to simply state what it means for the regulator output to be zero. The regulator’s output signal is 4~20mA, corresponding to 0~100%; when the output is zero, the signal value is 4mA. As for whether the valve is fully open or fully closed, it depends on its state; for electrically operated valves, it is fully closed ； The electrically controlled type is fully open.
Yes, this is the answer I wanted. Thank you!
I have a question, Master: are the so-called electric open/close valves and pneumatic open/close valves the same thing, or is what you mentioned referring to electric valves while mine refers to pneumatic valves?
"Electric on/off valves and pneumatic on/off valves serve the same purpose, but they differ in structure and working principle; the main difference lies in their power source – electricity for the former and air for the latter. For the regulator output signal, whether it is a electrically actuated valve or a pneumatically actuated valve, the signal remains 4–20 mA. For pneumatic control valves, an electrical converter is required; typically, the 4–20 mA signal enters this electrical converter, which then converts it into air pressure ranging from 0.02 to 0.1 MPa in order to regulate the valve.
Valves like the XV type are pneumatic, right? They can only be in the fully open or fully closed position. But there’s also an electromagnetic valve on them, which is used to control the flow of steam in and out of the cylinder. This is something different from the electrical converter, right?
There are only two states: \"fully open\" and \"fully closed\"; these are valves that operate in a on/off manner. In contrast, control valves in control systems can be in any state. The signals output by electrical converters are analog signals, while solenoid valves output switch signals – there is a big difference between the two...