5.3 Long Power Failure in Devices with an Interface
V
in
V
out
ok
Bat
Remote
from PC
Diagram 4: Long power failure in devices with an interface
Resumption of power supply when the buffering time tp is up (t3 is temporally after t4):
In the input voltage of the DC UPS module drops (time t1), the "Bat" battery immediately assumes the direct
voltage supply. In this way, the output voltage Ua remains absolutely uninterruptible.
The floating changeover contact "OK/Bat" switches to its resting position "Bat."
At time t2 selected by the user, the buffering time tp set at the DIP switches is started using the "Remote Timer
Start" signal (signal level = 0 at Pin 7 of the 9-pole serial interface or the "R" signal in case of USB
communication).
In the case of the selected "Output Ua Interruption" DIP switch setting, the output voltage Ua is automatically
interrupted for approximately 5 seconds when the set buffering time is up (time t4) and, at the same time, the
battery, which has not yet been disconnected due to a lack of input voltage, is deactivated from the output.
Note
: Without the remote signal level=0 with the time period setting of t=max, the output voltage is not
interrupted in this case because the set buffering time does not start (or, rather, it is interrupted only if the
exhaustive discharge protection disconnects the battery and the input voltage has not yet returned up to that
point).
DIP switch settings: Buffering at the maximum buffering time with Switch 1 Off (right)
Buffering time tp with Switch 2 through 7 from 5 to 635 sec.
Possible interruption of Ua using Switch 8 On (left)
© Siemens AG, 2009 13/18
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