Specifications

Mode 20: Up/Down Counter
Purpose
The counter in the HSIO circuit can count up/down signals from two separate sources (i.e.,
two single channel encoders) or two quadrature signal pulses. Quadrature signals are
commonly generated from incremental encoders, which may be rotary or linear. The
up/down counter has a range from -8388608 to 8388607. Using CT174 and CT175, the
quadrature counter can count at up to a 7 kHz rate.
NOTE: The count is 32 bit BCD sign + magnitude format.
Functional Block Diagram
The diagram below shows HSIO functionality in Mode 20. When the lower byte of HSIO
Mode register V7633 contains a BCD “20”, the up/down counter in the HSIO circuit is
enabled. For quadrature counting, input X0 is dedicated to the Phase A quadrature signal,
and input X1 receives Phase B signal. X2 is dedicated to reset the counter to zero value when
energized.
For standard up/down counting, input X0 is dedicated to the up counting signal, and input
X1 is dedicated to the down counting signal. The X2 input resets the counter to zero when
energized.
DL06 Micro PLC User Manual, 3rd Edition, Rev. C
E–24
Appendix E: High-speed Input and Pulse Output Features
1
2
3
4
E
6
7
8
9
10
11
12
13
14
A
B
C
D
Input Circuit
CPU
PLC
DL06
Y0 - Y1
X4 - X23
Y2 - Y17
V-memory
V7633
0020
Mode Select
I/O data
HSIO
Counter
Phase A
Reset
X0 X1 X2
O
utput Circuit
X3
Phase B
Filter
Input Circuit
CPU
PLC
DL06
Y0 - Y1
X4 - X23
Y2 - Y17
V-memory
V7633
0020
Mode Select
I/O data
HSIO
Counter
Up
Reset
X0 X1 X2
Output Circuit
Down
X3
Filter