How do you replace a battery on a SLC 500 CPU without loosing the program .

[Baker in Virginia]

Good Morning ,

How do you replace the battery on a SLC 500 CPU without loosing the program , since you need to remove the CPU , and the battery ? Is there a capacitor circuit in the CPU that will keep the circuit high for a certain amount of time ?

Thanks so much ,

 

[daba]

There is a capacitor on the board which maintains the memory for a substantial time (many minutes) when the battery is disconnected.

Have the new battery ready to go, and just change it as quickly as you can and you will be fine.

 

[Bit_Bucket_07]

The SLC 5/03, SLC 5/04, and SLC 5/05 processors have a capacitor that provides at least 30 minutes of battery back-up while the battery is disconnected. Data in RAM is not lost if the battery is replaced within 30 minutes.

http://literature.rockwellautomation.com/idc/groups/literature/documents/in/1747-in515_-en-p.pdf

 

[Mickey]

You should always have a backup though.

 

[Bit_Bucket_07]

you should always have a backup though.

+1

 

[daba]

http://literature.rockwellautomation.com/idc/groups/literature/documents/in/1747-in009_-en-p.pdf

see page 10

 

[James Mcquade]

you should always have a backup !

we have had 2 processors that had the capacitor go bad and lost the program everytime power went out, they even had a battery installed.

may not be your case, but a back up of the current program before you turn off the power is a sure thing.

james

 

[rootboy]

My recent experience with replacing the battery on a SLC was that the program didn't last thirty seconds, let alone thirty minutes.

So be sure to have your backup.

 

[Ron Beaufort]

the reason for that MIGHT be that the last person to "clear" the processor's memory didn't want to take the time to discharge the capacitor by shorting VBB to GND for about 60 seconds ... so he shorted the capacitor leads instead ...

oh - that'll discharge it quickly ... but ...

that's a LOT of capacitance in a very SMALL package - so a quick discharge might "punch through" the dielectric - and blow out the capacitor ...

and ...

the next time you need it - it won't hold up for long at all ...

the VBB to GND method provides a "bleeder resistance" to limit the capacitor's discharge rate ... shorting the capacitor's leads instead creates quite a "snap" ...

in any event - make sure that you HAVE A BACKUP PROGRAM! ...

 

[DwSoFt]

the reason for that MIGHT be that the last person to "clear" the processor's memory didn't want to take the time to discharge the capacitor by shorting VBB to GND for about 60 seconds ... so he shorted the capacitor leads instead ...

oh - that'll discharge it quickly ... but ...

that's a LOT of capacitance in a very SMALL package - so a quick discharge might "punch through" the dielectric - and blow out the capacitor ...

and ...

the next time you need it - it won't hold up for long at all ...

the VBB to GND method provides a "bleeder resistance" to limit the capacitor's discharge rate ... shorting the capacitor's leads instead creates quite a "snap" ...

in any event - make sure that you HAVE A BACKUP PROGRAM! ...

I love your posts. Always good information in it. Thanks.

 

[damica1]

the reason for that MIGHT be that the last person to "clear" the processor's memory didn't want to take the time to discharge the capacitor by shorting VBB to GND for about 60 seconds ... so he shorted the capacitor leads instead ...

oh - that'll discharge it quickly ... but ...

that's a LOT of capacitance in a very SMALL package - so a quick discharge might "punch through" the dielectric - and blow out the capacitor ...

and ...

the next time you need it - it won't hold up for long at all ...

the VBB to GND method provides a "bleeder resistance" to limit the capacitor's discharge rate ... shorting the capacitor's leads instead creates quite a "snap" ...

in any event - make sure that you HAVE A BACKUP PROGRAM! ...

I agree! It always pays to know the rest of the story. I take heed to every word this man has to say!!! (A wealth of knowledge)

 

[tomludwig]

I am a systems integrator and have been hired two times by customers with a SLC 500 where they let the battery completely die. In both cases they found the program, but one time they had to reach out to their retired former systems integrator and beg him to go into his old records and retrieve the program. One customer had me order the battery and install it, while the other had it. In both cases they needed my download cable and software to load the new program. Just to re-iterate what others have said. Always have a backup of your PLC and HMI and VFD settings (and other controller for that matter). If you are not sure, then hire an integrator to come in and assess your automation systems for this type of disaster recovery.