Battery in SLC 5/05

[TheWaterboy]

I'm ashamed to admit this but I've never had to replace a battery in a SLC. Some how been able to skip that task in all my years. So yesterday whet that came up, I noticed the battery is on the card and you have to remove the card to change it. (dumb.. so dumb)

So when I pull the battery to replace it in the unpowered state, will it lose the program like I would expect?

 

[joseph_e2]

Possibly. It's not supposed to, but be prepared for it to. They have capacitors that last long enough to swap the battery (plus <some time>) but they're likely not as strong as they originally were. I always connect and do an online save before taking it down.
As an aside, there's a reset procedure where you remove the battery and short 2 points on the board to drain the capacitors so it reverts to default. I think you're supposed to hold it shorted for like 1 minute or 5 minutes or something.

 

[OkiePC]

You have 30 minutes to swap the battery without losing the program and data assuming the capacitor is healthy. Never assume that and make a fresh upload just in case. I had a 5/05 on the bench unpowered with battery unplugged for a week and somehow it held onto the program, but don't expect to be that lucky. I have always made a fresh backup before a battery change to avoid being bitten by Murhpy's Law and so far, I've never lost a program.

 

[TheWaterboy]

OK that's what I was hoping for. I can't imagine it would be designed to allow that to occur easily but you never know.
Lets see if these old fingers still got it..........wait.....

 

[tlf30]

Wow, I admit I have also never had to change a SLC505 battery. I did not realize that it required removing the card. I just asked an I&C tech to replace one a couple days ago. I guess that is why he has not done it yet . Good to know for future reference. Such a poor design for process equipment that cannot be shutdown.

 

[joseph_e2]

Space constraints. The 5/01 and 5/02 have the battery on the front but starting with the 5/03, the 2 communication ports didn't leave enough space for the battery to be accessible.

 

[Operaghost]

Exactly, it was all about space. There just wasn't enough real estate available on those models once a serial port was added. I've had the capacitor hold a charge for several days. I think they gave the 30 minutes number as a worst case scenario. I've never had the capacitor fail on me, but certainly it is something to guard against with a fresh program upload.

One of the nicer aspects of that capacitor was that even if the battery was dead, you could still have an intact program after short power outages.

OG

 

[James Mcquade]

YES !
IT IS POSSIBLE to loose the program !
if the internal power supply that charges the battery and capacitor is bad, you will loose the program !
i have had that happen to me on 3 occasions in the last 5 years. we had spares and sent them in for repair.
as a safety, i always go online with the plc and upload the program and save it on the pc first.
if you do not have a spare, replace the battery, power the cpu up and if it has lost the program, you have it on the pc.
if it did loose the program, download the program, put the plc in run mode, then kill the power to the unit for 2 or 3 minutes.
then power the unit back up and see if it looses the program again. that will tell you what your next step is.
regards,
james

 

[Operaghost]

If the capacitor comes LOOSE, you might LOSE the program. Sorry, had to do it. My brain was hurting.

OG