Inserting A Backup Battery (Option) - Siemens SIMATIC S7-400 Installation Manual

6.8

Inserting a Backup Battery (Option)

Backup
Depending on the power supply module, you can use one or two backup batteries:
• To back 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.
You can 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). You can also back up
modules in an expansion rack via the EXT. BATT socket on the receive IM.
Inserting a Backup Battery
To insert the backup battery (batteries) in the power supply module, proceed as
follows:
1. Discharge any static charge by touching a grounded metal part of the S7-400.
2. Open the cover of the power supply module.
3. Insert the backup battery/batteries in the battery compartment.
Ensure correct polarity of the battery.
4. Switch on battery monitoring with the BATT INDIC slide switch, as shown in the
following table.
have a single-width power supply module,
have a double or triple-width power supply
module and want to monitor
a backup battery,
have a double or triple-width power supply
module and want to monitor both backup
batteries,
5. Close the cover.
Automation System S7-400 Hardware and Installation
A5E00850741-01
If You ... ...Then
set the BATT INDIC switch to BATT.
set the BATT INDIC switch to 1BATT.
set the BATT INDIC switch to 2BATT.
Commissioning
6-13