Back-Up Battery - Siemens Simatic PG 740 Manual

PG 740 Expansions
4.6
Battery Power
Supply for
Real-Time Clock
and Configuration
4
Battery too Low
Changing the
Battery
Resetting SETUP
4-16

Back-Up Battery

A back-up battery (3.6 V lithium battery) powers the real-time clock even
after the PG 740 is switched off. In addition to the time of day, all the
information about the PG 740's configuration is stored in RAM. 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.
If the battery voltage is too low, the current time and the configuration data
stored in the RAM are lost.
In this case, you must replace the back-up battery. The battery is located
behind the power supply module on the motherboard.
To change the battery, proceed as follows:
1. Switch your PG 740 off, unplug the power cable and detach all connecting
cables.
2. Open the unit as described in Section 4.1.
3. Undo the three screws of the bracing between the motherboard and the drive
support.
4. Remove the power supply by undoing the two screws on its right-hand side
and the two screws on the motherboard.
5. Unplug the power supply cable from the power supply.
6. Slide the power supply to the left as far as the stop. You can now lift the power
supply out of the unit.
7. Now replace the back-up battery, which is attached to the motherboard by
a short length of cable.
8. Fix the new battery to the motherboard with a cable binder.
9. Replace the power supply and close the unit as described in Section 4.8.
Caution
!
Risk of damage!
You may only replace the lithium battery with an identical battery or a
battery type recommended by the manufacturer of your PG 740
(Order No.:W79084-E1003-B1).
You should dispose of used batteries in keeping with local regulations. If
returned to the manufacturer, the battery materials can be recycled.
If you change the back-up battery, you must reset your PG 740's
configuration with the SETUP program (Chapter 5).
Programming Device PG 740
C79000-G7076-C742-01