Replacing The Backup Battery - Siemens SIMATIC PC 670 Equipment Manual

Maintaining and Extending the Computing Unit
4.3

Replacing the Backup Battery

Battery power supply for real-time clock and configuration
A backup battery (3.6 V lithium battery) powers the real-time clock even after the
unit has been turned off. In addition to the time of day, all the information about the
device (device configuration) is stored. If the backup battery fails or is removed
from its plug, these data are lost.
The clock uses very little power and the lithium battery has a high capacity so that
the battery can provide back-up power for the real-time clock for many years. The
battery seldom needs to be replaced for that reason.
Battery voltage too low
If the battery voltage is too low, the time is lost, and a correct configuration of the
device can no longer be guaranteed.
Replacing the battery
In this case, you must replace the backup battery. The battery is located on the
motherboard.
To change the battery, perform the following steps:
1. Disconnect the unit from the mains power supply and then disconnect all the
connection cables.
2. Open the device as described in section 4.1.
3. Change the backup battery inserted in the motherboard by pulling out the cable and
undoing the cable tie.
4. Secure the new battery in its mounting with a cable tie.
5. Insert the battery connector in the motherboard.
6. Close the device.
7. Connect the unit to the power supply again and press the Reset button (refer to
Chapter 4.11).
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Panel PC 670 Computing Unit, Equipment Manual
Release 04/02