Low battery LED lit while battery is ok of AB 1756-L61

[AB2005]

Hi;


I am experiencing a problem with AB 1756-L61 controller that it doesn't retain the program while battery is connected. I have found that when PLC is in the slot and power is ON, if we remove its battery, the low battery LED of controller is lit which is normal but when we install back the battery, LED remains lit and is off upon power cycle.
Battery is ok as its voltage is 3.2V. I have also replaced the battery but issue has not resolved.
I have flashed the controller, updated its firmware from 20.11 to 20.19, again downloaded the program but problem has not resolved.



Do you please help me out?

 

[Operaghost]

That is definitely a confusing issue.

When you say it is not holding the program after cycling power, is it empty with no program at all, or does it have some other program in it?

In the RSLogix 5000 software you can go into the Controller Properties and view the Minor Fault status. I have seen where people have clicked on the Battery fault check box. This is supposed to be a "read only" field that has a check next to it when you have a battery fault. But for some odd reason, they let you check the box which can prevent the fault from clearing.

OG

 

[arpus4KM]

have you tried something simple like putting a different battery in anyway? in the odd chance that it may be faulty, in the case that the voltage is good, but under any load it may drop down. have you tested the voltage while installed to make sure there is nothing drawing it down after being reinstalled?

 

[mylespetro]

have you tried something simple like putting a different battery in anyway? in the odd chance that it may be faulty, in the case that the voltage is good, but under any load it may drop down. have you tested the voltage while installed to make sure there is nothing drawing it down after being reinstalled?

I think he said he put in a replacement battery and the issue remains

 

[arpus4KM]

I think he said he put in a replacement battery and the issue remains

you are right, I missed that in the thick of it

 

[parky]

That's not how I read it, the OP seems to be saying if he removes the battery then the led comes on, replacing the battery the led does not go off until powered down & back up, this is normal, however, loss of program when battery is assumed ok sounds like a faulty processor, seen something like this on an old SLC, perhaps the OP could explain it a little clearer if powered down & back up does the led go off ?.