I have an application where I’m using 12 each Z-Wave switches that have normally open isolated contacts for controlling relays. The relays control motors, and other moving devices and can be controlled remotely through the Internet. The system works well, but I have the fear that in the event I’m a hundred miles away and the Internet were to stop responding, and if one or more of the motors were to continue to run; this would be very disastrous, and potentially dangerous. I’m currently using the Remotec model ZFM-80US. Any ideas on how to locally switch the relay on for a short period, maybe 5-7 seconds (or so), then it would automatically disengage. Remotely, turn it on again for another 5 seconds, and it would disengage, etc.
Since all the relays are in the same enclosure, I could fabricate a circuit board where each activation has a selectable time limit and then it would automatically disengage.
Any ideas would be appreciated.