4
4-19
PG 760 Programming Device
C79000-G7076-C761-01
4.7
Changing the Back-Up Battery
A back-up battery (3.6 V lithium battery) powers the real-time clock even
after the PG 760 is switched off. In addition to the time of day, all the
information about the PG 760 system configuration is stored. If the back-up
battery fails or is removed, all this data is lost.
Because the clock uses very little power and the lithium battery has a high
capacity, the battery can provide back-up power for the real-time clock for
several years. Thus the battery rarely needs to be changed.
If the battery voltage is too low, the current time and the configuration data
stored are lost.
In this case, you must replace the back-up battery. The battery is located
behind the power supply module on the motherboard (see Figure 4-3).
To change the battery, proceed as follows:
1. Turn off the unit, unplug the power cable.
2. Open the unit as described in Section 4.1.
3. Now replace the back-up battery, which is attached to the motherboard by
a short length of cable.
4. Fix the new battery to the motherboard with a cable binder.
5. Close the unit as described in Section 4.8.
!
Warning
Risk of severe personal injury or property damage, danger of release of
harmful substances.
There may be a danger of explosion if the battery is not handled properly.
Incorrect disposal of used batteries can cause the release of harmful
substances.
Do not throw a new or discharged battery into an open fire. Do not solder
onto the cell container. Do not recharge the battery and do not open the
battery by force.
The correct lithium battery can only be ordered from Siemens
(Order No.: W79084-E1003-B1).
Return used lithium batteries to the manufacturer/recycler or dispose of them
as special waste according to local regulations.
If you change the back-up battery, you must reset the configuration of your
PG 760 with the SETUP program (see Chapter 5).
Battery Power
Supply for
Real-Time Clock
and Configuration
Battery too Low
Changing the
Battery
Resetting SETUP
PG 760 Expansions