maintenance of an Allen Bradley PLC/SLC

What would be the most important things to check when doing a routine service of an Allen Bradley PLC 5 series PLC/rack and a SLC5000 PLC/rack?

There is very little to check in terms of maintenance.
Is the backup battery OK ? Check its expiry date.
If there are relay outputs, check if the number of operations are within the specified, check if the load is less than maximum permissible.
Apart from that I recommend to touch the mechanical parts as little as possible.

edit: Its not "maintenance" but heres a good advice: Check if you have a safe copy of the latest version of the PLC program

I would add that a check on the tightnees of all the connections in the panel is one of the most important parts of a panel/PLC PM program.

Listen to Jesper

Batteries - so important! We had to get a contractor in (I hate that) as an AB had lost its battery due to operators taking over changeover duties. This meant the machines were powered down on a regular basis and started to eat up the juice. The HMI has an alarm page which includes a low battery alarm - very thoughtful. However, because the icon didn't flash - it only changed colour - and there was no siren/cannon/erupting volcano, these same operators (dear sweet things, all of them) didn't notice the problem, or if anyone did they kept it to themselves. Episode 2 includes the fact that no-one had bothered to update RSLogix so our backup prog was useless, hence the contractor. Be warned!

---

PROGRAM - n. A magic spell cast over a computer allowing it to turn one's input into error messages.

Thanks, guys. Sounds like good advice.
One more simple question: does an Allen Bradley PLC 5 series PLC switch to program mode when doing an upload? What about the SLC's?
(OK, so that's two questions!)

AB PLC/SLC has to be in PROGram mode in order to Upload. You can however make ONLINE changes, but that's differnt than an upload which is transferring the program from your PC/Laptop to the controller.

just to keep the record straight ...

in Allen-Bradley systems ...

a DOWNload operation sends the program FROM the programming computer TO the PLC ...

an UPload operation brings the program FROM the PLC TO the programming computer ...

getting this one wrong has been known to make some very big messes ...

now to answer Pablo's specific questions ...

does an Allen Bradley PLC 5 series PLC switch to program mode when doing an upload? What about the SLC's?

Click to expand...

no ... the PLC-5 can stay in the Run mode while simply uploading a program ... actually, you're doing a type of upload operation every time you "save" the program to your programming computer ...

and the SLC's work the same way ... you can leave the program in the Run mode while you upload (or save) the program ...

What Ron said.

I alwasy gets those two confused. Again!

Upload is when the PLC is in a higher position than the laptop you loading the program from.
Download is when the PLC is in a lower position than the laptop you loading the program from.

Really :nodi:

The fine folk here have touched on it, but not come out and said in one simple sentence the most important bit of maintenance that should be done on ALL PLC's (and HMI's, and Drives, and anything with a comms port)...

Come up with a workable schedule, say every six months or so, and do a physical UPLOAD (save from device to PC) of every programmable device in your plant.

There is nothing worse than having a (albeit rare) failure of a device, replacing it, downloading a program that was 'Thought to be good', and then having to troubleshoot for another 8 hours to find that the sense of a contact was reverse due to the installation of a new limit switch 2 years ago.

Oh, yes. And change batteries. For Maintenance Scheduling, I usually advise all client to change every backup battery they can, every year. (And all at the same time). For Computer-Based HMI's, I advise changing the CMOS / Clock battery every two years.

Ron Beaufort said:

in Allen-Bradley systems ...

a DOWNload operation sends the program FROM the programming computer TO the PLC ...

an UPload operation brings the program FROM the PLC TO the programming computer ...

getting this one wrong has been known to make some very big messes ...

now to answer Pablo's specific questions ...



no ... the PLC-5 can stay in the Run mode while simply uploading a program ... actually, you're doing a type of upload operation every time you "save" the program to your programming computer ...

and the SLC's work the same way ... you can leave the program in the Run mode while you upload (or save) the program ...

Click to expand...

Can I Upload program from PLC-> SLC 5/03 to my PC without having the software at all.

Julian_ said:

Can I Upload program from PLC-> SLC 5/03 to my PC without having the software at all.

Click to expand...

NO, not to my knowledge.

Welcome to the forum Julian, but next time start a new thread, this is a 7 year old thread

Get a panel screwdriver and check every screw in the panel and all the remote panels. Any vibrations at all will eventually lead a strange shut-ins and intermittent faults.(Best to do this while the machine is down or can be brought down accidentally without damaging anything.
We do a backup of all systems every Christmas and July 4th of both computers and all PLC's to a portable 1Tb drive and the laptop we use for programming.