User Manual

LOGO! functions
4.4 Special functions list - SF
LOGO!
Manual, 06/2014, A5E33039675
181
● On-delay (Page 136) (current time Ta)
● Off-delay (Page 140) (current time Ta)
● On-/off-delay (Page 142) (current time Ta)
● Retentive on-delay (Page 144) (current time Ta)
● Wiping relay(pulse output) (Page 146) (current time Ta)
● Edge triggered wiping relay (Page 148) (current time Ta)
● Asynchronous pulse generator (Page 150) (current time Ta)
● Stairway light switch (Page 154) (current time Ta)
● Multiple function switch (Page 156) (current time Ta)
● Stopwatch (Page 171) (actual value AQ)
● Threshold trigger (actual value Fre)
Select the required function by the block number.
Timing diagram
Functional description
The threshold trigger measures the signals at input Fre. The pulses are recorded across a
configurable time G_T.
Output Q is set and reset in accordance with the set thresholds. See the calculation rule
below.
Calculation rule
● If the On threshold ≥ Off threshold, then Q = 1, if f
a
> On or Q = 0, if f
a
≤ Off.
● If the On threshold < Off threshold, then Q = 1 if On ≤ f
a
< Off.
Setting the Par parameter
Note
The system scans the counter limit value once per interval G_T.
View in programming mode (example):