4.4 Special functions list - SF
The time T
If the status of input Trg is 1 at least for the duration of the configured time T, the output is
set to 1 on expiration of this time (the output follows the input with on-delay).
The time is reset when the status at input Trg returns to 0 before the time T has expired.
The output is reset to 0 when the signal at input Trg is 0.
If retentivity is not set, output Q and the expired time are reset after a power failure.
When an on-delay is set, the output is reset when the configured time has expired.
Symbol in LOGO!
Note the parameter T defaults specified in topic Time response (Page 115).
The time for parameter T can be based on the actual value of another, already-configured
function. You can use the actual value of the following functions:
● Analog comparator (Page 165) (actual value Ax - Ay)
● Analog threshold trigger (Page 160) (actual value Ax)
● Analog amplifier (Page 173) (actual value Ax)
● Analog multiplexer (Page 194) (actual value AQ)
● Analog ramp (Page 197) (actual value AQ)
● Analog math (Page 209) (actual value AQ)
● PI controller (Page 201) (actual value AQ)
● Up/down counter (Page 151) (actual value Cnt)
Select the required function by the block number. The timebase is configurable. For
information on valid timebase ranges and parameter preset, refer to the On-delay
(Page 123) topic.
is triggered with a 0 to 1 transition at input Trg (T
is the current LOGO! time).
The off-delay timer starts with a negative edge (1 to 0
transition) at input Trg (Trigger)
A signal at input R resets the on-delay time and the
The output switches off (transitions from1 to 0) when
the delay time T expires.
/ = No retentivity
R = The status is retentive.
Q is set with a signal at input Trg. It holds this state
until T has expired.
Manual, 10/2017, A5E01248535-AA