ABB AC500 PLC Hardware Manual page 1110

Device Specifications
Accessories > AC500-eCo
5.
1110
Insert replacement battery.
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ATTENTION!
A standard batterie CR2032 can be used for TA561-RTC and TA562-
RS-RTC.
Nominal voltage: 3 VDC.
Required capacity: 230 mAh.
Required temperature range for discharge: 0 °C...+70 °C.
After replacement of the battery, the real-time clock (RTC) date and
time must be set again by the user.
Don't use a battery older than 3 years for replacement (e.g. battery
kept too long in stock).
Batteries must be stored in a dry place.
3ADR010121, 13, en_US 2019/04/17