Siemens SINUMERIK 840DE

03.06
8.1 Battery and fan replacement
8-92
© Siemens AG, 2006. All rights reserved
SINUMERIK 840D Configuring Manual NCU (PHD) – 03.06 Edition
The NCU features battery-backed SRAMs and clock modules. The NCU moni-
tors the backup voltage. The battery must be replaced within 6 weeks of a moni-
toring response. The battery/fan slide-in module in the NCU box can only be
changed after switching off the controller. The data is backed up for a period of
approx. 15 minutes.
The service life of the batteries used is at least 3 years.
The battery/fan subassembly is located under the DC link busbars (see Fig 3-3).
The slide-in module is replaced in its entirety.
Order number of the battery/fan slide-in unit: 6FC5247-0AA06-0AA0
1. Switch off the control.
2. Pull out the slide-in module. There is a latch (3) on the lower side of the
slide-in module, see Fig. 8-1. Press this latch (3) up and pull the slide-in
module forwards and out at the same time.
3. Install the new slide-in module. (within 15 minutes)
4. Switch the controller on again, the battery alarm should now be off.

Backup time
Replacement of
the battery/fan
slide-in module
8 Service and Maintenance