A stop signal stops two devices at the same time
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I have a question: In a DCS system, an emergency stop signal is used to stop two devices simultaneously. How should the wires for these devices be connected? Should the emergency stop signal wires of the two devices be connected in series or in parallel? Why
The DCS only needs to provide two DO outputs, which can be connected to the electrical control circuits of the two devices respectively; or one DO can be used, and then a relay can be employed to divide it into two signal nodes that are connected to the electrical control circuits of the two devices respectively.
It can be achieved in 2 ways: 1. Output 2 DOs to go to 2 separate devices. 2. Output a DO, add a DPDT relay, and connect 2 wires from this relay to 2 separate devices.
The control methods for the first and third floors will suffice. There’s no need to consider anything about parallel or series connections; it’s sufficient to just program it properly!
What about passive digital signals?
If your emergency stop button is located in the field control box, and two emergency stop buttons are required, they need to be connected in parallel to DI. If there is only one emergency stop button connected directly to DI, that will suffice. By implementing chaining in the program, it is possible to save one point in cost. If a quick stop button is added to the screen, a interlock can be implemented in the program.
Agree with the opinion from floor 3! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !
Thank you for your reply. My signal is a passive DO signal generated by DCS, and I don’t want to make any changes to the program configuration. Is it sufficient to connect the emergency stop circuits of the two devices together?
It’s simpler to use DCS for comparing two DO signals； Alternatively, a DO signal can be used to control the relay and thereby activate the electrical cabinet; in this case, an electrical control box needs to be added on-site.
As you requested, using a multi-contact relay is more suitable for this purpose!
It can be achieved in 2 ways: 1. Output 2 DOs to go to 2 separate devices. 2. Output a DO, add a DPDT relay, and connect 2 wires from this relay to 2 separate devices. This statement is the most accurate, and it can also be implemented logically