Siemens LOGO!, Manual

Page: 201 / 534

LOGO! functions
4.4 Special functions list - SF
LOGO!
Manual, 04/2011, A5E03556174-01
201
4.4.15 Up/down counter
Short description
An input pulse increments or decrements an internal value, depending on the parameter
setting. The output is set or reset when a configured threshold is reached. The direction of
count can be changed with a signal at input Dir.
Symbol in LOGO! Wiring Description
Input R A signal at input R resets the internal count value to
zero.
Input Cnt The function counts the 0 to 1 transitions at input Cnt.
1 to 0 transitions are not counted.
Use
•
inputs I3, I4, I5, and I6 for fast counting (only
LOGO! 12/24RC/RCo, LOGO! 12/24RCE, LOGO!
24/24o and LOGO! 24C/24Co): max. 5 kHz, if the
fast input is directly connected to the up/down
counter function block
• any other input or circuit component for counting
low frequency signals (typ. 4 Hz).
Input Dir You set the direction of count at input Dir:
Dir = 0: Count up
Dir = 1: Count down
Parameter On: On threshold
Range of values:
0...999999
Off: Off threshold
Range of values:
0...999999
StartVal: Initial value from which to begin counting
either down or up.
Retentivity for internal counter value Cnt:
/ = No retentivity
R = The status is retentive.
4
5
&QW
'LU
3DU
Output Q Q is set or reset, depending on the current value at
Cnt and the set thresholds.