Sensoray 425 - Manual (Page 13)

Page 11 Sensoray Model 425 Instruction Manual
Signal Pairs
Each counter channel is assigned three input signal
pairs. One pair connects to the A phase, one to the B
phase, and one to the index. All input pairs are
implemented as differential RS422 receivers.
Termination resistors are not supplied with the 425
board. If your encoder (or other signal source) employs
RS422 drivers, you may need to supply external
terminations near connector J1. Refer to your encoder
documentation for the recommended practice.
Encoder Power
Any connector J1 pins designated as +5V and GND
may be used to power encoders. Regardless of whether
or not an external power source is used to supply power
to an encoder, you must connect one of the J1 GND
pins to the encoder’s power supply return. Failure to
connect these returns may damage the 425 board.
If you are using an encoder or other pulse-generating
device that will be powered by the 425 board, connect
power signals as follows:
If you are supplying power from an external source,
make sure the device ground is connected to one of the
GND pins on J1:
Phase Connections
Some encoders have built-in RS422 drivers. If you are
using this type of encoder, connect it as follows:
Other encoders have TTL or CMOS outputs. If you are
using this type of encoder, connect it as follows:
Counter channels may also be interfaced to single-
phase devices. In such cases, the counter mode is set to
3 or 7, and the device is connected as follows:
Index Connections
Index signals, which are treated as active-low sources,
are connected in a fashion similar to that of the phase
inputs. In the case of a differential RS422 index pair,
connect the two signals to the +X and -X pins:
For a single-ended TTL or CMOS index, connect to the
-X pin and leave the +X pin disconnected:
Leave both +X and -X disconnected if you are not
using the index input.
Device
+5V
GND
VCC
GND
J1
Device
GND
VCC
GND
J1
External
Power
A
B
Encoder
+A
-A
+B
-B
J1
A
B
Encoder
+A
-A
+B
-B
n.c.
n.c.
J1
OUT
Device
+A
-A
+B
-B
n.c.
n.c.
J1
GND
X
Encoder
+X
-X
J1
X
Encoder
+X
-X
J1 n.c.