User Manual

LOGO! functions
4.4 Special functions list - SF
LOGO!
180 Manual, 06/2014, A5E33039675
4.4.17
Threshold trigger
Short description
The output is set and reset with two configurable threshold triggers.
Symbol in LOGO!
Wiring
Description
Input Fre The function counts the 0 to 1 transitions at input Fre.
1 to 0 transitions are not counted.
Use the following as the input:
• inputs I3, I4, I5, I6 for fast counting (only LOGO!
12/24RCE/RCEo and LOGO! 24CE/24CEo): max.
5 kHz, if the fast input is directly connected to the
threshold trigger function block
• any other input or circuit component for counting
low frequency signals (typically 4 Hz)
Parameter On: on threshold
Range of values:
0000...9999
Off: off threshold
Range of values:
0000...9999
G_T: time interval or gate time during which the input
pulses are measured
Range of values:
00:00 s...99:99 s
Output Q
Q is set and reset at the thresholds.
Parameter G_T
The gate time G_T can be provided by the actual value of another already-programmed
function. You can use the actual values of the following functions:
● Analog comparator (Page 188) (actual value Ax – Ay)
● Analog threshold trigger (Page 183) (actual value Ax)
● Analog amplifier (Page 195) (actual value Ax)
● Analog multiplexer (Page 213) (actual value AQ)
● Analog ramp (Page 216) (actual value AQ)
● Mathematic instruction (Page 227) (actual value AQ)
● PI controller (Page 220) (actual value AQ)
● Up/down counter (Page 173) (actual value Cnt)
● Analog filter (Page 232) (actual value AQ)
● Average value (Page 237) (actual value AQ)
● Max/Min (Page 234) (actual value AQ)