Protection of sensor and electrical wire conduits/trays from water
I have hundreds of sensors out in the rain, you just need to select ones rated for out door use. I preferr 24 volt models if your rack is 24 volt there is less chance of problems with water. The only one I could see a problem with is the thermocouple. If only high temp fiber insulation when the cable gets wet it can mess up your voltage and give inaccurate readings. This is solved with plastic insulationon the wires or the outer sheith. I like low voltage because I can have the wire going in free air to the mount where if 120v the eye or prox would need to be mounted in the junction box to protect the wires.