SIS interlock
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The lower-level unit in the SIS uses a PLC1200, while the upper-level unit uses WINCC; when the interlock conditions are met, the PLC stops operating. How can this be resolved?
What do you mean? Isn’t it very simple? Just connect your input to the PLC, write a program on the host computer, and then have the output sent to the field based on that program
Once the input conditions are met, the PLC stops operating, and the output is not sent to the field
1. The lower-level device in the SIS uses a PLC1200; can the PLC1200 meet the requirements of the SIS? 2. What signal should be sent to the PLC when the interlock conditions are met? Check the reason why it stopped running
Did the poster just start working? It’s one thing when the output doesn’t reach the field and another when the PLC stops operating. The PLC stopping operating means it has \"crashed\", while the failure to deliver the output to the field is due to issues with the PLC configuration, I/O cards, wiring, etc.; these need to be checked step by step. Generally, PLCs do not “freeze” because there is a watchdog to monitor them.
You didn’t make it clear either – do you mean achieving a situation where the PLC stops operating, or that the PLC stops working unexpectedly? An unexpected shutdown must be caused by a problem with the interlock system; check the logic first and then the wiring.
Once the PLC stops operating, doesn’t the program get interrupted? As a result, no signals can be sent to the field. The PLC stops working as soon as the interlock condition is met – is it because the manufacturer wrote the program incorrectly?
It means that if the PLC stops unexpectedly, the interlock function cannot be achieved
There’s nothing to do about it – the original poster isn’t majoring in instrument automation.
It’s clearly a problem unrelated to the program. Three directions: 1. Check whether the interlock output circuit is connected incorrectly, to the relay terminals of the power supply circuit. 2. Check the PLC power supply circuit to see if it is an independent circuit. 3. Check the grounding – ensure that grounding has been properly implemented, and that there is no interference causing the relay to operate incorrectly. 1200 is still very fragile
First, check whether there are any issues with the PLC power supply cables and interlock signal wires; there should be no interlocks in the program that would cause the PLC to shut down immediately.