MicroLogix 1400 - error code 0487h

Hello,

I need help with PLC error code. Major error S:6 = 487h. Which is known for The expansion I/O configuration in the user program did not match the actual configuration, or specified a module that what the module is capable of holding.

PLC has been running since long time. No update was performed at all. Suddenly, in the morning came across this error code.

Things I already tried:

1. Powered off PLC, reconnected all the modules. Powered ON. Still same error code.

2. Advance setting of IO configuration, clicked on ignore configuration error. Error goes away. But, Analog output module is not giving variable output anymore. It is giving minimum output. Due to which conveyor belt running at the lowest speed.


We have three analog Output modules in the panel. I ignored configuration error on module 4, then error goes to module 5. If I select for both 4 & 5, the error go to module 6. First, I thought it could be the output module but the same thing happed to rest of the analog module as well. So, it has to be PLC.


But, on the other end, once I ignore the configuration error for all Analog Output module, PLC runs the cycle and it is communicating with Digital Input and output modules. So, I am not sure what is causing this issue.


Can anyone help me out, here? I would really appreciate it.

Thank you

Welcome to the forum!

It sounds like your analog output module has failed. If it was previously working but then stopped communicating with the PLC, that would explain the fault, and would also explain the fact that it gives you minimum output when you disregard the fault.

You could try disconnecting and inspecting the connector, make sure you have no bent/dirty/corroded pins and so on, but given your description I'd be surprised if that helped - I'd suggest you'll likely need a new module.

Edit to add: I would suggest the module in slot 4 has failed, and it's preventing communication with all modules to the right of it. As you ignore each fault, the next module exhibits the symptom, purely because that's the first one in line that you're not ignoring.

Assuming all the analog output modules are the same type, you can test this by swapping the module in slot 4 with the one on the far right, and enabling the I/O fault for all modules except the last. If my suspicion is correct, all of the other modules will then work correctly, and only the last one will be faulty.

Thank you for your response. It was the module 4 which wasn’t communicating with PLC. Sent that one for repair. Because to get the new one, we need to wait for 26 weeks.