MicroLogix PLC: No Software Here. Still Upload it?

[Colt Hero]

We have this sub-system that was installed back in 2009, was never used, the building that used it was shutdown shortly after installation, and now the building is back up and running, the main system has been resurrected, and they want this sub-system working, too.

Problem is ... can't find the software anywhere!

Can I just hook up to it with another MicroLogix program, and when it cries "FOUL!", just upload whatever might be loaded in it, and SAVE it away?

It has power, there's a 2" PanelView on the door of the PLC enclosure - which also has power. When the E-STOP is pushed the alarm appears on the PanelView. And I can see two relays change state, and one DI I/O point turn ON when the door to the enclosure changes state. But I'm not sure if this means the program is loaded and running (or if it's just the I/O card receiving input).

Have gotten up into the ceiling where some Actuators are on what look like the water pipes, but when the START button is pressed, no sign of life. Will be getting an E&I guy involved to maybe scare up some wiring diagrams, but my question right now is about the MicroLogix program.

 

[drbitboy]

Yes, if you configure the comms to point to that MicroLogix, then select Upload, it will ask for a corresponding .RSS file, but you can also choose "Create new file," after which you should get the program, although without comments.

The question, I think, will be if the battery has been able to maintain the program, or maybe there has been power the entire time?

 

[Ken Roach]

In general, you can upload the user program from any A-B controller, including the MicroLogix, without having the source code already on your PC.

There are source code protection/password/comms lockout procedures that could prevent it, but they are uncommon.

The rung and address comments are not stored onboard MicroLogix controllers, so you will need to do a documentation effort to make the program usable for troubleshooting.

What model of MicroLogix (1000,1100,1200,1400,1500) ? Most of them had either nonvolatile memory or RTC batteries that would hold a program for many years (or indefinitely, for NVRAM).

When the E-STOP is pushed the alarm appears on the PanelView.

That is a very strong indication that the user program is loaded and running.

 

[OkiePC]

That is a very strong indication that the user program is loaded and running.

An even stronger indication is the green RUN LED right on the front of the controller.

If the PLC RUN LED is lit, then it is running a program. It might not be the right program, but if it has been mothballed and untampered with, it is likely the same one that was dumped into it years ago.