I have a question for everyone regarding on-site use and the normally open, normally closed functions, as well as series power supply in DCS systems
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Hello everyone, I have a question for you. How is the power supply circuit for these instruments connected? For example, for a DO point, a 220V or 24V power supply needs to be connected in series – how is that done? The DCS system in the control room is used to connect to the solenoid valves on site, and there is also a feedback signal sent from the field to the control room. I’m not sure about the wiring for these circuits; I hope someone can help explain it to me. It would be great if there were circuit diagrams available. Thank you
To feed the signal back to the DCS, an actuator needs to be equipped with a feedback switch or sensor; this operates in a separate circuit from the solenoid valve. As for the signal used to control the solenoid valve, it depends on the requirements of the DO points in your system – that is, the load capacity of those DO points, the voltage output, and other safety requirements – to determine whether an intermediate relay is needed to control the solenoid valve.
Solenoid valve ---- Relay ---- DO card, feedback ---- Relay or isolator ---- DI card. The power supply for relays is allocated by the DCS power distribution system.
If an additional power supply is to be used, how should the power supplies be connected? Could you draw a diagram?
It is usually powered by a card; how can it participate in sequential actions with separate power supply?
The control solenoid valve will not be powered by a stuck component; there should be a relay board that connects to the power supply. I’m from Rohde & Schwarz; here it is for your reference: http://mmbiz.qpic.cn/mmbiz/vGYzdsDAfVibZHHxJnKicEUJkT8ZQxNpzC6MU6N9Pmib3f7pMSBLpVqhQ8QaBCgq6d7sL3DhYhVMmWyiasiaqnCk2Yg/640?wx_fmt=jpeg&wxfrom=5&wx_lazy=1