Can DCS issue a shutdown command to the SIS system?
Thread Content
Can DCS issue a shutdown command to the SIS system? A problem arose in the project: the interlock design for the pumps is implemented in the SIS system, but the process requirements dictate that the DCS system be used for manually stopping the pumps (with pump start-up being done on-site). Is it possible for the DCS system to send a stop command to the SIS system? Please, an expert, explain it to me! It would be better if there were corresponding regulatory provisions. Thank you all first!
It should be impossible; the specific reasons will be clarified by experts. In my opinion, the signal triggering in SIS relies on hardwired signals from field devices, so it’s unlikely that this will work with DCS signals
It is best not to use SIS to control the start and stop of the pump. Personal understanding: Shutting down pumps in DCS is part of the normal production process, whereas SIS serves as a safety protection mechanism; the two should not be confused and should be handled separately. Modify the control in the electrical cabinet by adding a DCS pump shutdown button (it’s a very simple task)
If your pump is associated with risks such as material leakage, then the interlock for the pump should be implemented in the SIS. However, this is merely an interlock that leads to automatic shutdown of the pump (based on what you said, the pump starts manually on-site). Your process requirements call for a normal shutdown of the pump, and these two functions are different. In that case, you will need to ask the electrical team to modify the control schematic, so that the shutdown signal from the SIS is integrated into the main control circuit. It’s similar to an emergency stop function; the way in which the DCS handles pump shutdown remains unchanged. When the SIS is not active, it is still possible to shut down the pump using the DCS, and there is no conflict between the two methods. But once the conditions for shutdown via the SIS are met, automatic shutdown will take place
No. In principle, non-safety-related control systems should not be able to operate safety-related control systems, and safety-related manual shutdown functions should be built within the SIS platform.
Everyone needs to understand that SIS does not require human operation, got it?
No, you can issue a stop command directly through DCS; it’s not possible to do so via SIS
GBT50770-2013 5.0.9 5.0.10 Safety instrumented systems and basic control systems shall not interfere with each other’s operations; calculations
It’s not possible, but you can issue a command to stop the pump through DCS
Not allowed? Allowed? Not allowed? Allowed? You can say it’s allowed if you want, or you can say it’s not allowed – either works. The Party commands the guns; the equipment is for your use, so you can do whatever you want with it. Whatever you do, it’s considered valid; through such actions, truth is created. . . .