Rockwell Automation 1746-HSCE2 Multi-Channel High Speed Counter Module - Manual (Page 25)

Publication 1746-UM002B-EN-P - August 2004
Module Operation 2-5
Figure 2.4 Quadrature Encoder Configurations
Input Frequency Input frequency is determined by the input configuration as shown in
the table below.
12 11 10 9 8 7 6 5 4 3 2 1 2 3 4 5 6 7 8 9 10 1 0
6 5 4 3 2 1 1 0 2 3 4 5
1 2 3 1 0 2
11
Quadrature
Encoder
Input A
A
Forward Rotation
Input B
Input Z
B
Z
Reverse Rotation
A
B
X1 Count
X2 Count
X4 Count
IMPORTANT
The input configuration is limited by the operating
mode. In mode 1, Counters 1 and 2 can be assigned
any input configuration. In mode 2, Counter 1 can
be assigned any configuration, but Counters 2 and 3
are configured as pulse/internal direction. In mode
3, all counters have the pulse/internal direction
configuration. See the Summary of Available Counter
Configurations on page 2-8.
Input Configuration Input Frequency
X4 Quadrature Encoder 250 kHz
X2 Quadrature Encoder 500 kHz
All Other Configurations 1 MHz
IMPORTANT
The minimum high and low times for the pulse train
are 475 ns. Therefore, the input pulse train must fall
between a 47.5 to 52.5 percent duty cycle at 1 MHz.