Downgrade CompactLogix Firmware

[juanmdx]

Hello everyone,

I just wanted to know if it's posible to downgrade the firmware of a compactlogix, I have a 1769-L32E with firmware 20 and I have version 17 on my computer.

Is there any way I can downgrade the CPU?, I know I should upgrade mine but I want to know if I can downgrade it.


Thanks and best regards

 

[dmroeder]

Downgrading the firmware in the processor is no problem. The problem is going to be getting the program back into it. Changing the program from V20 to V17 will be impossible for you because you do not have V20 to start with. Even if you did have V20, it's not always very much fun.

There is a trick for downgrading a program but it does not always work the way you want. It involves saving your program as an L5K file (basically a text file), then editing it's version number. It will then let you pick a different version when importing it.

We have found several caveats with this method. It will corrupt some of the property windows of I/O cards. If you have advanced configurations like maps to other processors or produced/consumed tags it will not work.

If you start down this path and find out you cannot make it work, you won't be able to get the processor back up and running until you have a PLC program and processor firmware revision that match.

 

[juanmdx]

Thanks a lot for your answer, that's what I was looking for.

Best regards

 

[TConnolly]

If you have the program in Version 20 you can zip it and attach it to a post. Someone here with both versions can try downgrading the program to version 17 and repost it.

 

[dcooper33]

I occasionally have to use the L5K trick. All of our CLX programs are v20, with a FactoryTalk remote server as Security Authority. So whenever one of our corporate engineers wants to mull over a bit of logic, I will use the L5K file to turn the project into v19 so anyone can open it.
With the email, I usually add the caveat, "DON'T USE THIS ON A REAL MACHINE!"

 

[TConnolly]

When I want to make sure a program won't get accidentally used on a real machine I put a timer on the first rung and put
OTL timer.pre.31
right before the timer, guaranteeing that the preset will be negative and that any programmer will see that it was intentional, and hopefully clue in that the program is intentionally disabled.