Muffler Bearing
Aluminum
- Joined
- Jan 19, 2010
- Location
- KY, USA
I'm always trying to improve my knowledge on one topic or another. Lately, I've been reading a bunch about safety relays. My question is this - if you have one circuit that has the same purpose ("E-stop!") .. can the contacts be in series with one another? Note - this is not a question specifically for any particular machine.
Most manufacturers literature has the same variation of wiring diagrams. For every safety relay channel, there's always one e-stop NC contact, wired into the coil terminals of the safety relay, and then a monitoring loop contact that either has an identical contact or jumpered for automatic restart.
If you have 10 e-stop buttons, 2 pull cords, 3 door switches, each with two sets of NC contacts, what would be the problem with having one set of contacts of each device in series for the relay coil, and the other set on the monitoring circuit?
Most manufacturers literature has the same variation of wiring diagrams. For every safety relay channel, there's always one e-stop NC contact, wired into the coil terminals of the safety relay, and then a monitoring loop contact that either has an identical contact or jumpered for automatic restart.
If you have 10 e-stop buttons, 2 pull cords, 3 door switches, each with two sets of NC contacts, what would be the problem with having one set of contacts of each device in series for the relay coil, and the other set on the monitoring circuit?