overheating plc's?

[mc-motorsports]

Anyone have any input on overheating PLC's? Shop temps have been achieving 100*F as we start into August, normal for this time of year, but we have automated equipment "going stupid"... The PLC will complete the logic scan as directed, but will not restart the program as directed in automatic mode. It cycles for about 2 minutes as needed/parts loaded. It's a critical piece of the supply chain with a MicroLogics 1200 in a sealed enclosure, it locked up solid for 45 minutes the other day. I opened the cabinet and after cooling with a fan, went back to business as usual. Since then, I have installed a cooling fan on the operator station/electrical enclosure and haven't had a problem since.

keep in mind that I checked inventory, and we do not have a replacement in stock.

I discussed this with the EE, my argument was that a PLC should be able to tolerate 120*F, which I did not actually measure the cabinet temps, but I don't think it was over 120*.... I argued if the PLC was "going stupid" or otherwise overheating after operating for 10+ years in the same exact sealed enclosure, we should at least have a spare ready to change out.

I really didn't find any information on AB's website or manuals regarding overheating, only to avoid it.

Can anyone cite similar experience, or verify that the PLC is on it's way out the door?

Thanks

[Al_The_Man]

It does sound like an overheat problem, the fact that it has run for 10yrs OK probably means that some component or other has maybe degraded slightly with age, which can happen with electronic components.
If the ambient temp is 120F, it could be alot hotter on the surface of a component.
If it is a critical piece of equipment it might be a good idea to have a programmed spare on hand.
BTW. you can get temperature indicating tape that can be stuck on various surfaces that register a max temp detected by colour.
Al.

[Larken]

Put a small fan blowing on it . Get 12V fan with a wall adapter, or a cheap dollar storer fan. Even blowing on the outside will reduce the inside temp.

My son has a PS3 that crapped out. There is a guy on Youtube that tells that its the main graphics chip on the motherboard that runs extremely hot, (The PS3 even has a liquid cooled heatsink with a radiator fan !)

http://www.youtube.com/watch?v=4_Ic1_TY-GU]‪PS3 YLOD Fix Part 1 of 3‬‏ - YouTube

Anyway, he show taking the board out, putting it on a table and heating it with a heatgun to reflow it. I'm thinking that would never work.
So we do as he suggested, heat the board with my reflow hot air station and also a heatgun...any WOW it works again !!

[underthetire]

I haven't had PLC's overheat, but I have had old power supplies start putting out tons of AC ripple after getting hot, causing lots of strange issues. A couple new caps in them, and all was well in my world till something else broke.

[mc-motorsports]

No problems since I put a 5" fan to cool the enclosure. Still wondering how much longer the PLC will last... All of the company's more complicated equipment running multiple SLC and C-Logix racks have dedicated A/C units in the control rooms and or enclosures. The other thing I didn't mention is the PLC loses communication with a PC, we communicate via cable with SLC-500 software directly to a laptop, no wireless connection available. And when it's doing what it's supposed to do, no problems being online and monitoring the logic and inputs.

I have no doubts it was an over-heating issue, still arguing that it's a red flag the the PLC is on it's way to "brick" status...

[Al_The_Man]

I am not sure if the Micro1200 is supported anymore?
If not, may be look at swinging it over to a SLC500, these units can be had very cheap on ebay.
Al.

[zool]

Has the amount of amperage being pulled by various components and/or assemblies been checked?

It appears that there is something operating right at the failure level as it appears that it only when the temperature increases, AND that it has just appeared.

Given there are no replacements on the shelf, and MicroLogics 1200 is not supported any more, completing systematic analysis program would seem wise as the information gained can be used to:

1. Overhaul the faulting component[s] and/or assembly[s];

OR

2. Convince management its time to spend money to upgrade.

PS

Given the difficulties involved with Item 2, I hope it is Item 1 you can pursue!

[Al_The_Man]

IIRC, there is very little in the way of migration needed from the 1200 to the SLC500, I know AB used to offer a migration convertor for the older PLC2's & 5/15's.
It is mainly mechanical, i.e. mounting and moving the I/O connections over.
Al.