Should the instrument control interlock sections in the P&ID diagram be shown as process diagrams or instrument diagrams?
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Hello everyone, today there was a debate regarding this with the people from the engineering department. The process engineers say they don’t understand instrument control, nor do they know the difference between instrument signal wires and communication wires. They’re also unsure about how to draw the interlock diagrams for DCS and SIS. It’s our instrumentation team that should handle these interlock controls in the flow diagrams; they provide us with the interlock requirements, and after the diagrams are drawn, both teams sign off on them. I’ve also been working for almost 7 years now; previously, in my field of expertise, we were required to create instrument tag numbers, but this is the first time I’ve encountered the task of drawing flowcharts. Just now, the leaders from our department and the process engineering department also had a disagreement regarding this matter. I would like to ask everyone: in your work, which department is responsible for drawing the instrument control interlocks shown in the flowcharts? Are there any relevant standards that specify clear professional divisions? I would appreciate your advice.
This post was last edited by jujiangliu on 2018-5-8 10:28. The P&ID diagrams should be drawn by the instrumentation team. The instrumentation specialty creates P&ID diagrams based on the process flow diagrams of the process engineering specialty.
HG/T 20636 specifies the design requirements and division of tasks between the instrumentation and process engineering teams; the instrumentation team is responsible for receiving the PID diagrams, which are originally created through the joint efforts of several different teams
This post was last edited by “Hasty Passerby” on May 8, 2018, at 17:20. This division of labor probably isn’t exactly the same across all design institutes. In established processes, this issue doesn’t arise; however, it does occur in new processes and technologies. Logically speaking, the design of P&IDs should be carried out jointly by relevant engineering disciplines and the instrumentation discipline. The instrumentation discipline is better suited to handle the control and interlock aspects. In HG/T 20636.2-1998, under the section discussing the relationship between design requirements for automation engineering and those for process and systems engineering, the following description is given:
The process is improved; the instruments are adjusted in accordance with the specifications, and then returned. It is accomplished jointly by the process and instrumentation.
HG 20559.1-1993 \"Specifications for the Content and Level of Detail in Piping and Instrumentation Diagrams\" 1.0.9.1 Piping and instrumentation diagrams are primarily prepared by the process systems team; the main specialties involved include process engineering, automatic control, mechanical engineering, pumps, safety, environmental protection, commissioning, analysis and testing, as well as piping design and piping materials.
The question raised by the original poster covers two aspects: one is the content related to control interlocking, and the other is who will draw the diagrams. The content of control and interlocking is determined by the process engineering team, who provide the basic PID diagrams; on this basis, the instrumentation team makes the necessary modifications and improvements.
The instrumentation can be used to confirm the legends and drawing methods through process discussions, in conjunction with PID plotting, but the actual drawing work is carried out by the process team. According to the logic of your manufacturing process, the process parameters in the instrument specification sheet can be filled in by the manufacturing process itself later on.
The PID diagram should be drawn by process engineers, as it shows the interlock relationships – for example, which valve should be interlocked with a certain pressure – and it is the process engineers who are supposed to determine such things. Our instrumentation personnel modify the logic according to the requirements specified in the process, and then adjust the logic function diagram.
Completed through collaboration; the drawings should be double-signed by the process instrumentation team