Allen Bradley Micrologix 1200 Issue

Hello,

I have an 1762-OW8 output card which appears dead. The input/output cards to the right and left of it have power and are functioning. My electrician swapped the card out with a new one already (yes, he removed power to the PLC prior to replacing the card). What else could be causing this to happen that would be an easy fix prior to calling in an expert?

Is this a new installation?
When you are saying it "appears dead" is it 1. or 2.?

1. The CPU configured output relays are not switching states as commanded by the CPU running application file.

2. Nothing "happens" in the field when the dedicated relay is operated.

Scenario 1. might point to defective hardware (including the ribbon bus connectors!)
Scenario 2. could be as simple as a blown fuse for the supply (line) side of the relay outputs' circuitry.

If this is a new install, refer to Appendix F (System Loading Validation) of:

http://literature.rockwellautomation.com/idc/groups/literature/documents/um/1762-um001_-en-p.pdf

Reply

Was the card a like for like replacement? If so do you have access to the program and PLC? If you do while connected to the PLC open up the I/O configuration and make sure the correct card is selected in the slot that you replaced.

Is the PLC faulted? Is somewhat hard to tell from the picture, but it looks like the fault light is on.

My guess is that power was applied without the
ribbon cable attached and faulted the Plc (during
troubleshooting). You will have to go online to
clear the I/O fault and put back in run mode

In Picture PLC1, the Processor is clearly Faulted, and not in Run Mode, so the Outputs will not turn on in this state. You will have to go Online with the Processor, find out what the Fault is, and Clear it.

Stu....