Replacing The Backup Battery - Siemens SIMATIC PG 720 P Manual

5.5

Replacing the Backup Battery

Battery Power
A backup battery (3.6 V lithium battery) powers the real-time clock even
Supply for
after the PG 720 is switched off. In addition to the time of day, all the
Real-Time Clock
information about the PG 720 (device configuration) is stored in RAM. If the
and Configuration
backup battery fails or is removed, all these data are lost.
The clock uses very little power and the lithium battery has a high capacity
so that the battery can provide backup power for the real-time clock for many
years and seldom needs to be replaced.
Battery Voltage If the battery voltage is too low, the time of day and the device configuration
too Low
data in the RAM are lost.
Replacing the
In this case, you must replace the backup battery. The battery is located on
Battery
the drive mounting.
To change the battery, proceed as follows:
1. Switch off your PG 720 and remove the power cable and all the connecting
2. Open the unit as described in Section 5.1.
3. Now change the battery by removing the connector and releasing it from the
4. Push the new battery firmly into the clip.
5. Close the unit as described in Section 5.6.
Figure 5-6 Clip for Backup Battery
Caution
!
Risk of damage!
Only replace the lithium battery with an identical battery or with a type
recommended by the manufacturer (Order No.: W79084-E1003-B1).
Dispose of used batteries in keeping with local regulations.
Changing SETUP
After you have changed the battery, you must set the configuration data of
your unit again using the SETUP program (see Chapter 6).
PG 720 P Programming Device
C79000-G7076-C721-02
cables.
clip.
Clip
PG 720 Expansions
Backup battery
Hard disk drive
5-9