SLC 5/05 On Board Battery

[Scada Tom 0]

How often should the battery for a SLC5/05 be replaced? (this is the one for the processor memory)

[Ken Moore 23]

We replace ours every 18 months, but I do not know where this number came from. Edit: Found this in the SLC 500 Modular Hardware Style manual, I guess we are being extra cautious.

[Scada Tom 0]

Isn't 2 years how long it maintains the memory without power?

[Ken Moore 23]

That's the way I read it. So.... How long will it last when not in use, I would guess many years, but it all depends on the application. We have a pretty big maint. function for all our panels at the 18 month mark, changing the PLC battery is just one small item in a very large procedure. I'm sure we are changing them out prematurely, but if it saves me a midnight call, I'm for it.

[BobLfoot 302]

We have an annual 2 day power outage where we tear our distribution system 13.8 and 480 apart and clean and lube everything. We also have two to three building cleanings by heating the interior to 135 F and holding it there for 24 hours. Of course all PLC's are powered down before the temp is raised. As a result we change our batts annually rather than put up with the midnight calls to reload programs when a batt fails unexpectedly.

[paulengr 44]

I don't know about the others but I can positively verify that around 165-170 F on the metal shell of a 1771-L40E, it will shut down. Drop down to 155 F and it starts right back up like nothing ever happened. This is with the power supply right beside it and a full rack of I/O. Don't know for how long or how many times that a PLC-5 can tolerate this but it was routinely running for months and months in the 120-140 range every day for 3-4 hours.