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CONTROL PANEL
ETV 1591-H
24.03.2015
Page 17
5.3
UPS Operating Modes
Limit at which the operating mode of the UPS is changed.
5.3.1
Switching to Battery Operation
The UPS monitors the main supply voltage in order to switch to battery operation when the
+24 V main supply fails. When a violation of the value limits is detected, the UPS switches
the source of the buffered supply from the +24 V main supply to the battery and back.
Operating Mode
Threshold
(hysteresis)
Meaning
Main supply OK
>19.4 V (±0.4 V)
The ETV 1591-H function block is powered by the +24 V supply.
The battery can be charged.
Main supply failure
<18.4 V (±0.4 V)
The ETV 1591-H function block is powered by the UPS battery.
Battery connected to a load.
5.3.2
Low Battery Charge Conditions
With the battery voltage measured under load, the low charge condition can be determined.
Contrary thereto, the charging or open circuit voltage cannot be evaluated. The voltage
under load is used for example, to immediately shut down Windows when a critical charge
condition is reached.
Status
Batter Voltage
(loaded)
Meaning
No critical status
>13.2 V
Battery normal.
Battery warning
≤13.2 V
The battery must be charged (recommended: >5 h)
The capacity of the battery is sufficient to safely shut down the
operating system (maximum 60 seconds).
Critical battery warning
≤12.8 V
The battery is has reached a very low charge, it is possible the less
than 60 seconds of buffering cannot be provided. Windows is
immediately shut down after a main power failure by the Windows
service "SigmatekUpsMonitor"
Battery critical
≤12.3 V
Deep discharge protection threshold of the battery. The UPS
deactivates the entire system so that the battery is not burdened
further.
The operating system is no longer shut down.