Siemens SIMATIC PG 720, Manual

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3
3-17
PG 720 Programming Device
C79000-G7076-C720-02
3.6 External Power Unit and Battery
The external power unit is used to supply the PG 720 with power when it is
being operated with 115 V or 230 V mains supplies. The voltage is set
automatically. In mains power supply operation, the integrated battery is
charged at the same time. The connecting cable to the PG 720 has an external
power supply unit. For connection to the power system, the external power
supply unit has a connector for non-heating appliances.
Figure 3-10 External Power Supply Unit
!
Caution
Danger of overheating!
The external power supply unit can be damaged if the ventilation slits are
covered.
Do not place any objects on the ventilation slits.
The PG 720 has an integrated nickel-cadmium battery. This makes the unit a
portable device that can be used when no mains power supply is available.
The battery also prevents loss of data if there is a power outage.
Once the external power supply unit is connected, the battery is charged. The
following conditions are important:
S
When charging, the battery temperature must be b 5
°
C and
+ 40
°
C (40
°
F and 100
°
F).
S
Charging stops as soon as the battery is fully charged.
S
In storage, a fully charged battery runs down in approximately 2 months.
It must then be re-charged.
Note
Whenever possible, avoid running down the battery too far. Switch off the
unit when it is not in use.
Before the battery is completely discharged, the red power LED lights up.
External Power
Unit
Battery
Getting to Know the PG 720