Siemens Simatic RTU303xC Series Operating Instructions Manual page 172

Configuration (WBM)
4.18 Operating mode
● Connect battery
By clicking the button, you connect the plugged in battery module and its expansion
modules logically with the RTU.
Without the connection on this WBM page, the RTU does not access the physically
plugged in battery module.
When connecting the RTU checks the voltage level of the batteries in the battery module.
It detects empty or defective batteries as well as incorrect physical connections of the
batteries. You should therefore check the feedback in the WBM to make sure that the
batteries have been accepted by the RTU.
● Disconnect battery
Note
Disconnection necessary for battery replacement
Without the disconnection in the WBM, the RTU continues to access the physically
plugged in battery module.
By clicking the button, you disconnect the plugged in battery module and its expansion
modules logically from the RTU.
The RTU checks whether a disconnection is permitted in the current operating situation.
Disconnection is only possible if the RTU is supplied either via the external power supply
or via the other battery module at this point in time.
If at the time of disconnection another battery module with an adequate voltage level is
connected, the RTU switches internally to the other battery module and releases the
module to be disconnected for a battery change.
Battery switchover
● Use the preset value
Enable the option if the RTU is to use the preset voltage value of 80% as the signal for
switching over the battery modules.
By default, the RTU switches over to the second battery module when the voltage value
of the first module falls below 80% of the nominal voltage of 7.2 volts, which means a
threshold value of ≤ 5.76 V.
When this option is disabled, you can enter a different threshold value manually. In rare
cases, this can be practical, for example when connected sensors put heavy load on the
battery with high current peaks.
172
Operating Instructions, 06/2019, C79000-G8976-C382-06
RTU303xC