User Manual

LOGO! functions
4.4 Special functions list - SF
LOGO!
Manual, 06/2014, A5E33039675
147
● Stairway lighting switch (Page 154)(current time Ta)
● Multiple function switch (Page 156)(current time Ta)
● Stopwatch (Page 171)(actual value AQ)
● Threshold trigger (Page 180) (actual value Fre)
Select the required function by the block number. The timebase is configurable. For
information on valid ranges and parameter defaults, refer to Section "On-delay (Page 136)".
Timing diagram
Functional description
A 0 to 1 transition at input Trg sets the output, and triggers a time T
a
during which the output
remains set.
LOGO! resets output Q to lo (pulse output) when T
a
reaches the value preset at T (T
a
= T).
LOGO! sets the output immediately if there is a 1 to 0 transition at input Trg before the
specified time expires.
If the block is retentive, LOGO! resets output Q and the expired time to the values before a
power failure; if the block is not retentive, LOGO! resets output Q and the expired time to
defaults after a power failure.