I need to accomplish 2 things at low cost of course:
1) Detect a short and wire it into a sinking plc input
I was thinking to wire +24v to the coil of a relay and the short to the other side of the coil and then using the contact for my plc input. Its for detecting an antenna is plugged in so I don't want to risk damaging it either.
2) Detect that a light has turned on by sensing current or resistance change on the 12V feed and then turn on a sinking plc input with that detection
Not too many ideas on this one.
1) Detect a short and wire it into a sinking plc input
I was thinking to wire +24v to the coil of a relay and the short to the other side of the coil and then using the contact for my plc input. Its for detecting an antenna is plugged in so I don't want to risk damaging it either.
2) Detect that a light has turned on by sensing current or resistance change on the 12V feed and then turn on a sinking plc input with that detection
Not too many ideas on this one.