Micro Logix 1000 outputs don't work

Hello everybody,

I've had an issue with MicroLogix 1000 [FONT=&quot]1761 – L32BWA. Somehow I had shortcut wire from PLC output with COM. Output voltage was +24 VDC that I got from PLC. After that controller disabled all the outputs. Inputs are working but ouputs not. How can I troubleshoot this issue?

So to explain again... I had active relay output (+24vdc) and touched wire with wire of DC COM. Since then not single output works...
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It sounds like you burned out a common wire to ALL your relay outputs. Fix: Buy another PLC (less trouble and time) or if you can solder and have a magnifying glass, some tools, and steady hands, open up the case and go to work.

It could be that the burned wire or fuse is inside, between the PLC power supply and the 24 VDC Power Out terminals. If so, your relay outputs may still work, if your Output LEDs still go ON. If so, you could power your Outputs with an external power supply (DC or AC). Your relay outputs actually will operate from AC or DC, from 5 VAC/VDA up to 125 VDC or 264 VAC.

You might want to use a fuse between your Power supply and your PLC COM output terminals, just in case you accidently do it again!

Welcome to the forum.

I know that not the news you wanted to hear, but Lancie is probably correct. Unless you have blown a fuse somewhere else in your circuit then you have most likely destroyed the PLC. The ML1000 is a throw away brick. You'll have to replace it and then download a new program to it.

Are any of the PLC indicator lights on? Is so which ones? Maybe take a photograph of it and post it. Maybe you got lucky. If you didn't destroy the PLC then you should take a quick trip to over to Monaco and visit the Monte Carlo casino while your luck holds.

@TConnolly

Welcome to the forum.
I know that not the news you wanted to hear, but Lancie is probably correct. Unless you have blown a fuse somewhere else in your circuit then you have most likely destroyed the PLC. The ML1000 is a throw away brick. You'll have to replace it and then download a new program to it.

Are any of the PLC indicator lights on? Is so which ones? Maybe take a photograph of it and post it. Maybe you got lucky. If you didn't destroy the PLC then you should take a quick trip to over to Monaco and visit the Monte Carlo casino while your luck holds.

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I have no LED indication that output is active and it's forced in RSLogix, for every input I have indication, and for power and force... Better to get a magnifying glass and solder

On the upside they make great paperweights that are a constant reminder of a stupid mistake. At least mine is... I haven't made that same mistake again so I guess it's working??? Hope you get it figured out.

Kraken Fan #69

Ouch. Good luck, a down PLC just plain sucks.

I have no LED indication that output is active and it's forced in RSLogix, for every input I have indication, and for power and force...

Click to expand...

Did you try feeding your outputs with an external power source? You could be lucky and the part that got burned was the internal connection from the Micrologix internal 24 VDC power supply and the 24 VDC (+) and (-) teminals. That is not likely but possible. It would be easy to check with some external power source, either DC or AC in your case.

Can you still measure 24 volts between the MicroLogix + and - 24 terminals?

Lancie1 said:

Did you try feeding your outputs with an external power source? You could be lucky and the part that got burned was the internal connection from the Micrologix internal 24 VDC power supply and the 24 VDC (+) and (-) teminals. That is not likely but possible. It would be easy to check with some external power source, either DC or AC in your case.

Can you still measure 24 volts between the MicroLogix + and - 24 terminals?

Click to expand...

I have tried to get external source, but relays dont work (they dont close the circuit). There is 24V between the MicroLogix + and - 24 terminals.

Sorry for your loss. You need to kiss this one goodbye.

Lancie1 said:

Sorry for your loss. You need to kiss this one goodbye.

Click to expand...

Hehe, thanks for your help anyway

Are you certain the program is still loaded and the controller is in RUN mode ?

Shorting the +24VDC "sensor power supply" on a 120V AC supply model MicroLogix can result in the user program being deleted.

The output indicator lamps do not (as far as I know) depend on the actual output field voltage; they are powered by the internal circuitry of the controller, just like the input status lamps and the RUN mode lamp.

I had a similar experience. Since it was a brick (I thought) might as well open it up & see what's inside. I found a blown 5x20mm fuse so I replaced it and then it worked again. I don't remember exactly what I did to cause the failure but was glad not to have to buy a new one.