Commissioning
6-13
AutomationSystem S7-400 Hardwareand Installation
A5E00850741-01
6.8 Inserting a Backup Battery (Option)Backup
Depending on the power supply module, you can use one or two backup batteries:
•Toback up a user program and save it without loss in the event of a power
failure.
•For retentive storage of bit memory,timers, counters, and system data as well
as data in variable data blocks.
Youcan also provide this backup with an external battery (5 to 15 VDC). You
achieve this by connecting the external battery to the EXT.BATT.socket on the
CPU (see Reference Manual,CPU Data Section 1.2). Youcan also back up
modules in an expansion rack via the EXT.BATT socket on the receive IM.
Inserting a Backup Battery
Toinsert the backup battery (batteries) in the power supply module, proceed as
follows:
1. Dischargeany static charge by touching a grounded metal part of the S7-400.
2. Openthe cover of the power supply module.
3. Insertthe backup battery/batteries in the battery compartment.
Ensure correct polarity of the battery.
4. Switchon battery monitoring with the BATT INDIC slide switch, as shown in the
following table.
If You... ...Then
have a single-width power supply module, set the BATTINDIC switch to BATT.
have a double or triple-width power supply
module and want to monitor
a backup battery,
set the BATTINDIC switch to 1BATT.
have a double or triple-width power supply
module and want to monitor both backup
batteries,
set the BATTINDIC switch to 2BATT.
5. Closethe cover.