Installing And Removing The Backup Battery - Siemens SIMATIC Panel PC 870 Equipment Manual

Servicing and Expanding the Computing Unit
4.6

Installing and Removing the Backup Battery

Battery supply for clock and configuration
A backup battery (3.6 V lithium battery on the motherboard; see Fig. 4-2) ensures
that the hardware clock will also operate when the device is switched off. In
addition to the time of day, the device configuration is also stored. In case of a
failure of the backup battery or disconnection from the plug contact, these data are
lost.
Thanks to the low current consumption of the clock and the high capacity of the
lithium battery, the battery is able to backup the clock over several years. It is
therefore only seldom required to replace the battery.
Battery voltage too low
If the battery voltage is too low, the current time of day is lost, and no correct
device configuration is guaranteed any more; in this case, the battery must be
replaced.
Changing the battery
Proceed as follows:
1. Disconnect the device from the mains and remove all interconnecting cables.
2. Open the device as described in Section 4.1.
3. Change the backup battery by removing the connector from base X49 of the
motherboard (see Fig. 4-3) and remove the battery from its holder.
4. Attach the new battery in its holder and connect the battery connector to the
motherboard.
5. Close the device.
Warning
!
Risk of personal injuries and material damage; risk of emission of hazardous
substances!
If handled incorrectly, a lithium battery can explode; failure to dispose of old
batteries in accordance with the relevant standards can result in the emission of
hazardous substances.
The lithium battery must only be replaced by identical types or types
recommended by the manufacturer (Order No.: W79084-E1003-B1).
Do not throw new or discharged lithium batteries into the fire; do not solder at the
cell body; never try to discharge lithium batteries and do not open them with
violence.
As far as possible, exhausted lithium batteries should be returned to the battery
manufacturer/recycler or be disposed of as special waste.
4-16
SIMATIC Panel PC 870 Computing Unit, Equipment Manual
Release 11/02