5.2 Brief Power Failure in Devices without an Interface
© Siemens AG, 2009 12/18
Diagram 3: Brief power failure in devices without an interface
= with setting of interruption Ua; DIP Switch 8 On (left)
V
in
V
out
ok
Bat
Resumption of power supply before the buffering time tp is up (t3 is temporally before 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 the same time t1, the buffering time tp set on the DIP
switches starts automatically. If the "Output Ua Interruption" DIP switch setting is selected, the output voltage Ua
is automatically interrupted for 5 seconds after the buffering time tp (time t4) is up. The battery is already switched
off because the input voltage has returned to time t3. f the DIP switch is not set to "Output Ua Interruption," there
is no interruption in this example because the input voltage at time t3 has already returned before the set buffering
time (time t4).
DIP switch settings: Buffering according to a set time using Switch 1 On (left)
Buffering time tp with Switch 2 through 7 from 5 to 635 sec.
Possible interruption of Ua using Switch 8 On (left)
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