Siemens SIMATIC Field PG P4 Manual page 47

Performing a Calibration Cycle
Broadly speaking, the procedure for a calibration cycle is as follows:
1. Before starting battery calibration, you have to select SIMATIC battery
calibration under Control Panel > Power Options, than deactivate the
options Activate battery alarm when power level reaches in the tab Alarms
under Control Panel > Power Options.
2. Battery operation: Discharge the battery until the battery LED on the device
changes from red to green. To do this, remove the power supply from the Field
PG P4.
Duration: max. 3 hours.
3. Power supply operation: Fully charge the battery (without interruption) until
the battery LED on the device changes from orange to green. This will take a
maximum of 4 hours if the device is switched off. (Optional: to reduce the
recharge time, switch off the device if possible).
You can carry out an automatic calibration cycle with the "Field PG" panel (see
section 3.5).
SIMATIC Field PG P4 Manual
A5E00180080-04
Configuring And Operating The SIMATIC Field PG P4
3-7