There is a problem with the DCS card in the device
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There is a problem with the DCS card in the device; all control valves cannot be operated, and their positions remain fixed at the values they had before losing control. What could be causing this? I’m not very familiar with the DCS structure; could any experts help me understand it? What role does the card play in the device? What role does the cabinet room play?
What manufacturer’s system? All control valves have lost control – wasn’t there any redundancy in the controller? They generally feature fault-free, disturbance-free switching. Unless you are a very small system and not from a major DCS manufacturer. Card types include control cards, communication cards, IO cards, etc. The cabinet room is where the cabinets are placed; inside those cabinets, there are cards, safety barriers, switches, and so on.
Which DCS is being used? Also, first check whether all the control valves you mentioned are controlled by the same output card Does your home have safety guards? If you say that it should remain in the state before losing control, it means that your channel setting uses \"retain after power loss\" or that your safety gate configuration is set to \"retain\"; check whether the status light of this output card is working properly.
It’s not necessarily a card failure; what is the model of the CPU? The same issue can occur even if it isn’t running.
Has it experienced consecutive limit-downs? There’s no reset
It is recommended to first check the card component to see if the status indicators and output signals are working properly! Power off the card, turn it back on and check again; if that doesn’t work, the card might be damaged!
The card serves to convert your control output into a current of 4–20mA on a proportional basis, which is then sent to the valves on site via the safety barrier. Thus, to check the malfunctioning circuit, follow this sequence: DCS card output port — safety barrier inlet and outlet — valve positioner signal reception — valve positioner operation (check whether the current matches the set value)