Rockwell Automation 1746-HSCE,D17466.5 High-Speed Counter Module - Manual (Page 163)

1 Publication 1746-UM006B-EN-P - August
Appendix
C
Differential Encoder Information
This appendix describes the wiring procedures for connecting a
differential encoder to the module.
Connecting a Differential
Encoder For proper module operation, wire the encoder so that the Z input
signal is high (true) at the same time the A and B input signals are low
(false). If this condition is not met, inconsistent homing may occur.
If you are using an Allen-Bradley Bulletin 845H differential encoder,
this condition is met by following the wiring diagrams in this manual.
The following instructions describe how to connect a differential
encoder to the module.
1. Obtain the encoder output timing diagram from the encoder
data sheets.
2. On the timing diagram, look at the Z input signal and its
complement Z signal. Whichever signal is low for most of the
encoder revolution and pulses high for the marker interval
should be wired into the Z(+) terminal. The remaining signal
should be wired into the Z(-) terminal.
3. Look at the B input signal and its complement B signal.
Whichever signal is low for at least part of the marker interval
should be wired to the B(+) terminal. It is possible that both
signals meet this condition. It this is the case, either signal may
be wired to the B(+) terminal. The remaining signal should be
wired into the B(-) terminal.
4. Look at the A input signal and its complement A signal.
Whichever signal is low for at least part of the marker interval
should be wired to the A(+) terminal. It is possible that both
signals meet this condition. It this is the case, either signal may
be wired to the A(+) terminal. The remaining signal should be
wired into the A(-) terminal.