How do valves at different control stations interlock with each other
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This post was last edited by sunjun*2010 on 2017-4-7 08:38. Currently, one control station in my DCS system has 4 valves, while another control station has 1 valve; all of them are ball valves. I would like to implement interlocking between these valves – is that possible? And how should it be done?
Are you referring to different stations within one system, or two separate systems? There should be no problem with different stations within the same system, right?
For general safety requirements, the relevant components are located in one control station; two control stations are required to enable inter-station communication in order to function. . Otherwise, it cannot be used.
For inter-station communication, it is necessary to transmit the status of the conditions that require interlocking to the station where the valve is located; however, interlocking between two or more stations is not recommended. One more thing: how do you communicate between stations? (Is it fiber optic cable, network cable, or a 9-pin cable?)
It is highly recommended not to use inter-station communication; in my case, inter-station communication is achieved through a central control serial port card. We have encountered situations where, after an alarm indicating a failure in the main controller, the indicators for inter-station communication showed abnormal readings. It is recommended to use a one-input two-output safety barrier for this purpose; I have adopted this solution for all my critical inter-station communications. If it’s really not feasible to implement this approach, then there is no choice but to use regular inter-station communication
Yes, it’s supported; signal separation at the hardware level is better. Even if a problem occurs, it will be limited to just that one component, and there won’t be multiple alarms or failures occurring simultaneously
The valve position status feedback safety barrier has been changed to a one-input two-output configuration, and is assigned to two stations
It was solved with just a small gauge!! ! The instrument operates independently of the control system to control these two or more valves in a interlocked manner; the control system can also monitor and control each valve. In the event that communication between the control stations is lost, this control instrument can still ensure proper valve control. Low investment, reliable and stable!
It’s best not to use communication for connecting points; although it is convenient, its failure rate is quite high!