ceilingwalker
Lifetime Supporting Member
Good day all. I have a SLC500 with a 5/04 processor and a relay output module 1746-OW16. I have an output that energizes a mag relay that applies heat to an acid dip tank.The heater in this tank has a one-shot fuse to protect it from overtemp. So the circuit goes from output module, to one-shot fuse at the tank, back to the control cabinet, then to the coil on the mag relay. What is happening is, the heater gets to temp set point, the output module denergizes, however, the coil remains pulled-in.So the tank keeps overheating and the only way to denergize the coil is to remove the wire from the coil itself or the wire between the coil and the one-shot fuse. I don't believe the module is the fault but I'm not sure. When I remove the wire from the contact point on the module the coil does not drop-out and the module does not read a voltage across it. This is not a new system, it has been in place and functioning for quite some time. I'm not sure if I have entirely ruled out the module or not, however, it seems that removing the wire and not reading voltage across that terminal point on the module,tells me the module is not the fault here. Any feedback would be greatly appreciated. Thank you much.