Overview
1-8
Series
505 High Speed Counter
and Encoder Module User
’
s Manual
Counting Modes (continued)1.5.2
Quadrature
Mode
For quadrature mode, each channel counts according to rising and/or
falling edges. T
ypical devices for quadrature inputs are optical encoders.
Different quadrature modes are selected based on the resolution required
by the application and the encoder used.
1.5.3
1X Quadratur
e
The module counts on the edges of the A input pulses.
When input A leads input B, the HSC counts up on each rising edge of
input A.
When input B leads input A, the HSC counts down on the falling edge
of input A.
Figure 1-5 illustrates the relationship between inputs A and B and the
count value in
1X Quadrature mode.
Count Value
1X Quadrature
12 10
A
B
25s
min
Count Up
(A Leading)
Count Down
(B Leading)
26.7
s
min
Figure 1-5
1X
Quadrature Mode