Rockwell Automation 1746-HSCE2 Multi-Channel High Speed Counter Module - Manual (Page 23)

Publication 1746-UM002B-EN-P - August 2004
Module Operation 2-3
Pulse/Internal Direction
When the Pulse/Internal Direction configuration is selected, a bit
written from the backplane determines the direction of the counter.
The counter increments on the rising edge of the input if the bit is low
(0) and decrements on the rising edge of the input if the bit is high
(1).
Up and Down Pulses
In this configuration, the counter increments on the rising edge of
pulses applied to input A and decrements on the rising edge of pulses
applied to input B.
Figure 2.3 Up and Down Pulse Configuration
TIP
When both inputs transition simultaneously or near
simultaneously, the net result is no change to the
count value. Therefore, simultaneous (or near
simultaneous) pulses are ignored and no change in
the count value is reported.
1 2 3 2 1 0 1 2
Input A
Input B
Input Z
Incrementing Encoder
or Sensor
Increment Pulse
(count up)
Increment Pulse
(Input A)
Decrementing Encoder or
Sensor
Decrement Pulse
(count down)
Decrement Pulse
(Input B)
Count
Module