unsaint32
Member
I have a 24v prox with three wires. I do not have COM available for 24v+. Can I just use the 24v+ & GND to power the sensor? It's not a critical input. It just sees a part. If the sensor fails, nothing will move after that.
No. You cannot use ground as a current carrying conductor. Unless it's a '74 Duster, the answer is no.
I had one of those, Gold Duster. Only memory is a cracked exhaust manifold.
If it is genuinely a two wire sensor then the +Ve lead will go to +24v of the plc input supply, the output will go to an input and the -ve will go to the PLC common, this is unusual to have two wire DC sensors and not sure if the load of the input will be enough for a DC prox.
https://slideplayer.com/slide/4468776/14/images/25/Sourcing+Two-Wire+Inductive+Proximity+Sensor.jpg
Question on grounds and commons, is it acceptable to tie the grounds between two different panels that have two different power supplies (AC or DC)? What about tying 24V common / neutral between two different power supplies?
For grounds it is usually a good idea to ground everything connected together into one common bonded ground point. There can be a potential voltage between 2 separate ground rods on panels at different locations, and if the panel and the machine have individual ground rods.
Always try for a single ground point and have good bonding throughout.