Micrologix 1500 processor replacement

[JohnRatHolten]

Hey All,

A question about replacing the Procesor module on a MicroLogix 1500.........

We have a machine that we bought last year, there is an inherent problem of the PLC (or the program) causing our system to occasionally fault,
and we have to switch the PLC from REM to PROG, PROG to RUN, and back to REM.

The OEM acknowledged the inherent problem when they commisioned the machine and the Tech/Eng made sure he
told everyone what to do about it.....

Apparently, someone tried to do that and managed to break the switch (and of course no one will admit to it)……
Luckily, it is stuck in the REM position, and I was able to plug in my laptop and go online to clear the fault.
The OEM did give me a copy of the program, but has since been unresponsive to my requests for information.

I bought a replacement processor just in case the switch fails completely..... This is a 1764-LRP
Now, I’ve not had any real experience with setting up a ML1500, so I figured I ask a few things before I attempt anything.
I see that the processor module snaps into the base unit and the programming port (channel 0) is on the base unit
connected to an Ethernet Interface, which is how I go online.

Are the communication protocols between the Ethernet interface and the base unit predefined?
Can this be as easy as snapping in the new processor, and downloading the program through the Ethernet interface?
Or, is it more involved than that (I read something about a comms toggle push button on the processor)??

Any input would be appreciated.....

Regards,
JohnR

 

[Mickey]

Can this be as easy as snapping in the new processor, and downloading the program through the Ethernet interface?

Yes , as long as the serial port is at its default setting. Check the offline program.

Have you looked at the fault under processor status, error tab to see what it is? You might be able to fix it so you don't have this issue anymore.

 

[George Graziano]

Most of the errors "tell you something". What is the error?
George
Sorry Mickey. You beat me too it. I misread your post thinking you were showing them where to look for a revision number.

 

[JohnRatHolten]

oh yeah, just that easy......
thanks guys.....

I've been wanting to check the error code, but I've only had to deal with the problem twice, first time I flipped the switch, next time was when the switch was broke and I was under the gun to get it running, you all know how that goes....

hopefully, next time I'll be at my leisure to research it a bit.

regards,
JohnR

 

[OkiePC]

The last ML1500 I had with an intermittent fault:
The code was pointing to an add on (analog card) in first expansion spot.
We replaced it first. Problem returned. It also was sometimes pointing at the adjacent slot. After we had already played musical analog cards, the problem remained even with two new cards, with the old cards, and re-seating all the connectors did not help.

So, I ordered up a new processor. It had been a while since I dealt with the ML1500 (4 years). When I picked up the order, I thought the box seemed sort of small. I opened it up and suddenly remembered that "Oh yeah", this processor slides into a base.

So a couple things here, you have to be able to slide the CPU out of the base to swap it. In our case the fault was in the base not the CPU, so be aware that your root cause of the faults might be in a whole 'nuther catalog number.