Siemens SIMATIC S7 System Manual page 774

Technical specifications
A.9 Battery board signal boards (SBs)
Diagnostics
Critical battery level
Battery diagnostic
Battery status
Battery status update
Table A- 154 Wiring diagram for the SB BA01 Battery board (6ES7288-5BA01-0AA0)
SB BA01 Battery board (6ES7288-5BA01-0AA0)
774
SB BA01 Battery Board
< 2.5 V
Low voltage indicator:
Low battery voltage causes the LED on the BA01 panel
•
to illuminate with the red light continuously ON.
Diagnostic alarm and/or digital output status of battery
•
low condition available
Battery status bit provided
0 = Battery OK
1 = Battery low
Battery status is updated at power up and then once per day
while CPU is in RUN mode.
System Manual, V2.3, 07/2017, A5E03822230-AF
S7-200 SMART