Siemens Simatic M7-400 Reference Manual page 368

Interface Modules
Installation and Removal of the Modules During Operation
Please read the following warning on the insertion and removal of the interface
modules and associated connecting cables.
Caution
!
Data may be lost or corrupted.
Removing or inserting the interface modules and/or their associated connecting
cables under voltage can result in the loss or corruption of data.
Switch off the power supply modules to the CC and EUs you are working on
before you carry out any changes.
Feeding in External Backup Voltage to the "EXT.-BATT." Socket
(Not Possible in Modules as of Order Number -0AA01-)
When changing the battery in the power supply modules of the S7-400, you can
ensure uninterruptible backup in the CC if you apply between 5 VDC and 15 VDC
to the "EXT.-BATT." socket of the CPU. This only provides backup power to the CC.
You can achieve corresponding backup in an EU in the case of the following
receive IMs by applying between 5 VDC and 15 VDC to the "EXT.-BATT." socket.
• IM 461-0
• IM 461-1
• IM 461-3
The "EXT.-BATT." input has the following features:
• Reverse polarity protection
• A short-circuit current limit of 20 mA
To provide an incoming supply at the "EXT.-BATT" socket, you need a connecting
cable with a 2.5 mm ∅ jack, as illustrated in the following figure. Note the polarity of
the jack.
Plus pole
6-6
6ES7461-0AA00-0AA0
6ES7461-1BA00-0AA0
6ES7461-3AA00-0AA0
Minus pole
Jack 2.5 mm ∅
S7-400, M7-400 Programmable Controllers Module Specifications
A5E00069467-07