I can’t understand the DCS and SIS in PID diagrams
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Learning a new craft; I had no prior experience in production. The PID diagram indicates that the interlock sequence is sometimes DCS first, followed by SIS? Or is my way of putting it incorrect? I would like to ask how to correctly read the instruments in a PID diagram; thank you.
Generally, the first page of a PID diagram will contain explanations for the relevant symbols
The instructions suggest that there is a sequence to follow, but a colleague said that interlocking doesn’t involve any sequence – what’s the actual situation?
Basically, it’s that the PID-based DCS systems and SIS are hard to understand, right?
Your question is too vague for others to understand; it’s not specific enough to answer. Just address the issue directly – if there’s a diagram you can’t understand, upload it directly so that others can help you figure it out
I see. Thank you for your kindness, but there is a confidentiality agreement regarding the drawings, so I’m afraid I can’t upload them. Please understand
Generally speaking, the priority level of SIS is higher than that of DCS; for many interlock shutdowns, if SIS is available, they are carried out solely within the SIS
DCS instruments are process flow instruments, while SIS is a safety system instrument system that uses PLCs. Controlling two systems that are not the same can be considered separately.
The sequence of sequential triggering is generally determined by the process requirements regarding which valve should be activated first. Your question is a bit vague; typically, DCS sequences and SIS sequences do not include redundant triggers
Generally, the first page of a PID diagram will contain explanations for the relevant symbols