Hot Swapped compact logix card

Well, I screwed up majorly. I wasn't paying attention to what I was doing and pulled a card on a compact logix while it was still running. My set up is the controller, power supply, 3 DI's, 3 DO's jumper to 3 AI's, power supply. I have all of my DI's, none of my DO's, the LED on my AI's is on, but my plc isn't reading any data off of the AI's. Just wondering what it could possibly be?

Hello and Welcome

In your first part you state ControlLogix and in the second part you state CompactLogix

What is your part number to the CPU?

Have you gone online and tried to see if any errors are stated and are any fault lights on the CPU? if you have a key switch try turning it to stop and back to run

sorry, I meant compact logix

the only switch is a program, run, remote switch, the "ok" led is blinking red. Everything except the DI cards are showing to be ok, the DI's have 25vdc on them, but they are not working. I replaced all 3 with cards I know are good and still no change.

Do you have the software? you may need to reload the program/reset the CPU

Try turning the switch to program then back to run and see if that clears the issues, I think you have a I/O error in the program and it needs to be reset

andrew.saldana said:

the "ok" led is blinking red.

Click to expand...

This means you have a recoverable fault and needs to be rest, try the key if that does not work you need to go into the software and reset it

Ok, I do have the software. Ill hop on and see if I can reset it. Thanks.

The keyswitch should be able to clear it, I have seen situations where you have to go between run and stop twice to clear the fault and get it back into run mode. Do it slowly and give it time to restart.

The only switches i have is run rem prog.

You guys were great. Got online & reset it. Everything is working good. Thanks for all the good info.

:site:

Just to complete the picture for you: by default, local modules on a CompactLogix are configured to fault the PLC if the connection is lost. By pulling a card out, you caused the PLC to fault.


When the PLC is faulted, all of your inputs will still work, inasmuchas you press the button/actuate the sensor, and the corresponding light on the input module will come on. That's all hardware-level stuff, and no matter what's going on in the PLC, that will all "work". So that's whay you "had all your DI's". Of course, the PLC is not actually doing anything with those changing inputs.


On a PLC fault, digital outputs will all go to the configured fault state, which by default is off. The LED's on the output modules will indicate as such by also turning off. So that's why you had "none of the DO's".


Analog inputs don't have individual LED's, just an "OK" LED, which as you said was on. That's because the connection to your PLC was just fine (after you replaced the card you removed, presumably). As long as the analog card can connect to the processor, and the card itself is physically healthy, that LED will be on. I'm not sure what you meant by "my plc isn't reading any data off of the AI's". My best guess is that you have a HMI connected to the PLC, and it was just showing "frozen" values and not updating as the measured variable changed. Am I correct? That would be because the PLC has stopped executing the code, including the scaling from your analog inputs. When the PLC faults, all tag values stay exactly as they are and do not change. The HMI can read and write tag values to and from a faulted PLC just fine, and won't otherwise tell you that anything is wrong. But while the PLC is not executing code, there's nothing to make it update the values according to the data from the analog inputs.


Anyhow, hope that fills in a few blanks for you, and glad you got it up and running again!