Standard representation method for chains
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This post was last edited by Gentle man on 2023-12-28 at 10:19. Hello, experts! I believe you all have many years of experience in automation control, and you must have encountered numerous interlocks in system PID diagrams. I would like to ask: what is the proper and correct way to draw interlocks? Those who know the answer please offer some guidance! ! Here is a system PID diagram we obtained. It’s impossible to understand this sequence of connections; it seems that the way in which these connections are shown is incorrect. As shown in the figures below, these two diagrams represent one system, with the output port on the right side of the upper diagram connected to the input port on the left side of the lower diagram. With so many such connections, there are only two sequence numbers, which is quite strange
The standard way of representing chains should be clear and standardized. If the chain drawing shown in the figure is difficult to understand, it might indeed be non-standard. A proper sequence should have clear sequence numbers, and every action and feedback should have a distinct way of being represented. It is recommended to refer to relevant industry standards or drawing specifications for verification and modification. .
The interlocks in PID are merely used to indicate that a certain sensor is involved in a particular interlock, or that a certain interlock controls a certain pneumatic valve; to understand the details of the interlocks, one needs to refer to the interlock logic diagram or the cause-and-effect table.
The interlocks in the P&ID diagram only represent signal relationships, without indicating logical relationships. To understand the logical relationships, one should read the interlock logic diagram.