Rockwell Automation 1755-OF8 GuardPLC Controller Systems - Manual (Page 110)

110 Publication 1753-UM001C-EN-P - March 2010
Chapter 12 High-Speed Counters
Counter Mode/Direction and Reset
In pulse counting with direction and reset, the state of input B is
evaluated in addition to counter input A.
When the B input has a low signal while the counter recognizes a
negative pulse edge at its A input, the value of the counter is
incremented by 1. When there is a high signal at the B input, the
counter is decremented by 1.
The counter is released or reset via the Z input. The counter is
released when there is a constant LOW signal at the Z input. A
constant HIGH signal halts the counter and a short-time HIGH signal
resets the counter value to 0.
To enable the counter to function correctly, configure these
parameters in the routine.
Parameter Setting
Cnt[0x].5/24V Mode true for 24V
or
false for 5V
The adjusted level also applies to inputs B and Z.
You must configure this parameter with a constant.
Cnt[0x].Auto Advance Sense true to count up and down simultaneously
Cnt[0x].Direction true to decrement (counts from 16,777,215 downward)
or
false to increment (standard setting)
Cnt[0x].Gray Code false
Cnt[0x].Reset true
If this parameter is set to false, the counter value is
reset to 0.