1746-ob16 problem

Replacing a PLC with a SLC 500, we had a problem with a 1746-OB16. During checkout we found a loose wire on the DC comm to this card, once lifted every output on the card went on. Note: the outputs in this case are SS relays in motor starters. Note: the ouput LED did not change state just the outputs went high. Has anyone else seen this, is there a fix other than making sure the wire is secured?

The outputs all went ON, and actually energized the relays on the starters?

If so, I'd think initially that you need more loading across the outputs. Example: Put a half-watt, 1200 ohm resistor directly across each SS Relay input to common.

SS Relays don't need a lot to drive them, so without a common on the output module, the outputs may have floated high enough to energize the SS relays.

Me thinks I need 1746 OW16.

cornbread said:

Me thinks I need 1746 OW16.

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Possible, but not absolutely necessary. For similar, or probably less cost, you could get DIN mount solenoid drivers, that look like terminals with micro relays in them.