User Manual

LOGO! functions
4.4 Special functions list - SF
LOGO!
180 Manual, 04/2011, A5E03556174-01
● Off-delay (Page 164) (current time Ta)
● On-/off-delay (Page 166) (current time Ta)
● Retentive on-delay (Page 168) (current time Ta)
● Wiping relay(pulse output) (Page 170) (current time Ta)
● Edge triggered wiping relay (Page 172) (current time Ta)
● Asynchronous pulse generator (Page 175) (current time Ta)
● Stairway
light
switch (current time Ta)
●
Multiple function switch (Page 182) (current time Ta)
● Stopwatch (Page 198) (actual value AQ)
● Threshold trigger (Page 210) (actual value Fre)
Select the re
quire
d function by the block number. The timebase is configurable. For
information on valid ranges and parameter defaults, refer to the On-delay (Page 160) topic.
Timing diagram
7
7/
7UJ
4
7
7DLVEXV\
Functional description
A 0 to 1 signal transition at input Trg sets output Q. The next 1 to 0 transition at Trg
retriggers the current time T
a
, and output Q remains set.
Output Q is reset when T
a
= T. You can output a warning signal before the off-delay time (T -
T
!
) has expired to reset Q for the time of the pre-warning period T
!L
.
A further one-shot at input Trg during T
a
retriggers the time T
a
.
If retentivity is not set, output Q and the expired time are reset after a power failure.