How is it best to connect the emergency stop button to the I/O unit?
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Is it connected using solid wires? What signal to use, what is the level of signal loss, and what signal anti-interference measures to take
Hardwiring is used; since it’s a button, the signal type is DI. A 1.5mm2 control cable is employed because it’s in a control room, so there’s no significant signal loss.
The emergency stop button must be wired hardwired. The system shutdown button DI terminal is connected to the system; in the case of compressors or pumps, etc., it is directly connected to the shutdown circuit in the MCC control cabinet.
Hard wires are used for connection; the emergency stop button is a digital switch.
The emergency stop button is connected directly to the terminals of the DI card in the DCS via wires.
The control room does not require shielding; ordinary computer data cables are sufficient. If it refers to indicator lights, it’s the same way: from the auxiliary control panel to the card
^_^Of course, it’s done with hard wiring, as that’s the most direct and reliable method. If the signal power supply is stable, there will be no interference. If the operation distance is large and the path passes through sources of interference, a cable with a shielding layer can be used, with the shielding layer grounded
The emergency stop button is used as a DI input to the system.
If the emergency stop button is more than 2,000 meters away from the DI point, how can reliability be ensured and accidental activations reduced?
Hard wiring; consider debounce measures.
To reduce accidental activation of the emergency stop button, a dual-button system can be used: one for stopping and the other for confirmation; both are necessary. This is exactly the system used for protecting steam turbines from stopping.:lol