User Manual

LOGO! functions
4.4 Special functions list - SF
LOGO!
174 Manual, 06/2014, A5E33039675
● Analog ramp (Page 216) (actual value AQ)
● Mathematic instruction (Page 227) (actual value AQ)
● PI controller (Page 220) (actual value AQ)
● Up/down counter (actual value Cnt)
● Analog filter (Page 232) (actual value AQ)
● Average value (Page 237) (actual value AQ)
● Max/Min (Page 234) (actual value AQ)
● 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 (Page 180) (actual value Fre)
Select the required function by the block number.
Timing diagram
Functional description
The internal counter increments (Dir = 0) or decrements (Dir = 1) by one count with every
positive edge at input Cnt.
You can use input R to reset the internal count value to the start value. As long as R = 1, the
output is also 0 and the pulses at input Cnt are not counted.
If retentivity is not set, output Q and the expired time are reset after a power failure.
Q is set or reset depending on the current value at Cnt and the set thresholds. See the
calculation rule below.