DCS-controlled electric valve
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How are electric valves controlled by DCS used for switching? Please provide more specific details, thank you
Two-position electric valves provide digital output, while electric valves with continuous adjustment provide analog output
Depending on the functions of the electric control valve, if it can only receive digital signals (DO signals), then the control system uses DO digital output cards to control the opening and closing of the valve. If the electric control valve requires continuous adjustment, then the control system employs AO analog output cards; the output signal is usually of the 4-20MA type, and its control principle is similar to that of ESDV valves or control valves. There is no difference for control systems; the system merely sends signals, and it is the inherent functions of the electric control valve that determine how its functions are carried out
This depends on the format of the signal from the electric valve. The first type is bus-controlled: in this case, the DCS communicates with the bus controller of the electric valve, and the bus controller uses a 485 line to control the electric valve on site. The second type is the standard type: the DCS DO points are used directly to control the opening and closing of electric valves. Typically, there are two DOs (one for opening and one for closing), and three DI inputs (1 for local/remote control, 1 to indicate proper operation, and 1 for comprehensive alarms). This should be accepted as the best answer.
I would like to ask about the switching status of the 220V electric valve – what is its status, and is it powered?
It should be called valve position feedback! 4-20MADC
If you don’t understand, please don’t speak recklessly. What is 4-20madc?
What the original poster is asking about is implementing a switch; they didn’t mention implementing adjustment
The 4th floor is the correct answer: one DO is sufficient to solve the problem, and two DI channels can be used to provide feedback signals. As for comprehensive alarms, they are optional……
It’s simple for DCS engineers, but it’s difficult for those who have no experience with it at all to explain it clearly in just a few words. It is recommended to ask an engineer to resolve it. Brief description: 1) Circuit wiring: DCS DO points are connected to the secondary circuit of electric valves (control switches), while DCS DI points are connected to the feedback signals from the electric valve switches – one point for each. (For control valves that use 4–20mA current control, AO/AI points are used.) 2) DCS configuration: The relevant circuits in the DCS are configured, with parameters such as point type, signal type, and range assigned. 3) HMI configuration: Configure the screen using FIX, create the corresponding screens, and connect to the relevant DCS points.
Give a like to the person upstairs; I’ve learned something: lol