Siemens FEC920 User Manual page 120

ONE SHOT
If the trigger input is active, countdown timing is initiated as soon as the entered time value is confirmed (scroll
key). The entered time decrements to zero, and must be re-entered by the user before any further timer function
can be initiated.
Rules
1. The time value decrements only when the trigger input is active.
2. The output is On only when the trigger value is active (and the entered time value has not elapsed).
3. The entered time value can be edited at any time to increase or decrease the remaining time period.
Elapsed time
MIN ON
Note: For ease of comparison the two time edits in the figure above were both to the same value.
This is not a necessary condition.
This 'Off delay' function provides an output signal that goes 'on' when the trigger goes active and remains on
for a specified period after the trigger goes inactive.
If the trigger goes inactive, then active again before the time period has elapsed, then the elapsed time is reset
to zero and the output remains on.
The 'Triggered' parameter is on whenever the elapsed time is counting down.
Elapsed time
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FEC920: USER GUIDE
Trigger
τ
Time
Output
Time edits
Time
Triggered
Figure 102 'One Shot' timer definitions
Trigger
Output
Triggered
Figure 103 'Min On' timer definitions
A5E45696052A Rev-AA
τ τ
1
Time Time
2 = Time
Time
September 18