Siemens SINUMERIK 840DE User Manual page 94

8 Service and Maintenance
8.1 Battery and fan replacement
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.
Backup time
The service life of the batteries used is at least 3 years.
Replacement of
The battery/fan subassembly is located under the DC link busbars (see Fig 3-3).
the battery/fan The slide-in module is replaced in its entirety.
slide-in module
Order number of the battery/fan slide-in unit:
1. Switch off the control.
2. Pull out the slide-in module. There is a latch (3) on the lower side of the
3. Install the new slide-in module. (within 15 minutes)
4. Switch the controller on again, the battery alarm should now be off.
8-92
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.
SINUMERIK 840D Configuring Manual NCU (PHD) – 03.06 Edition
6FC5247-0AA06-0AA0
© Siemens AG, 2006. All rights reserved
03.06
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