There are several forms of DCS interlock logic diagrams
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The other party requested the DCS configuration files; not understanding this, I sent over the operational logic in text form, for example: if PT2010A is greater than 0.35 Mpa, reduce the frequency of P2021 until PT2010A reaches 0.35 Mpa. The other party replied that they still needed the DCS control interlock diagram. . Professional DCS software doesn’t do this; when you see a table like the one below, is this a form of DCS interlock logic diagram?
It shows that they understand more than you do; what they need are the source files (the original project files), which are very important for subsequent maintenance, along with the causal relationship tables.
This requires a high level of expertise; ordinary technicians might not be familiar with it
It’s not clear whether you are the turnkey supplier responsible for the design, or it’s a design institute or something else. . . Is the other party a DCS manufacturer or the owner? Different entities require different information.
The poster’s diagram is the logic schematic, which is also used for configuration. I’m currently checking the design provided by the design institute, and I find that there are still conflicts with the process requirements. In my opinion, the control logic merely outlines the objectives that the process is meant to achieve; it is the configuration architecture that forms the basis for the instruments to meet the process requirements through logical decisions. Therefore, a supplier may not be able to develop a complete system based solely on your written descriptions, unless they are very familiar with your process.
It’s a kind of chain logic diagram, but the causal relationships aren’t very clear……
The poster is likely Party B. If it’s a design institute, these files used for DCS configuration, as well as interlock logic diagrams and cause-and-effect tables, are all discussed during the negotiation of the design scope. The design institute creates these documents based on the information provided by the process package supplier or patent holder. However, some complete set of equipment-related documents need to be provided by Party B to the client; after the client reviews them, they can either proceed with secondary design or directly hand them over to the DCS manufacturer for configuration. This also depends on the original design scope and the extent of responsibility assigned to the design institute； If the owner is Party B, then provide the necessary information in accordance with the provisions of the technical agreement. After all, as the manufacturers of the equipment, you have a better understanding of the logic and requirements related to its protection. If you don’t provide this information to the owner, it will be very difficult for them to carry out subsequent work and complete the project.
Basic instrument interlock logic: the valve is closed when the liquid level is high. There is also LV2109, which is a manual valve controller; the reset takes precedence over the interlock logic
What they want is the source code for DCS; just providing logic diagrams isn’t enough~
It is an interlock logic diagram; no interlock conditions were found. The evaluation is complete.