User`s guide

20 • Signal Connections
Here are two examples of connecting the input signals with the external
circuits. The input circuits can connect to the encoder or motor driver,
which are equipped with: (1) differential line driver or (2) open collector
output.
u Connection to Line Driver Output
To drive the PCI-8134 encoder input, the driver output must provide at least
3.5V across the differential pairs with at least 6 mA driving capability. The
ground level of the two sides must be tight together too.
u Connection to Open Collector Output
To connect with open collector output, an external power supply is
necessary. Some motor drivers also provide the power source. The
connection between PCI-8134, encoder, and the power supply is shown in
the following diagram. Please note that the external current limit resistor R
is necessary to protect the PCI-8134 input circuit. The following table lists
the suggested resistor value according to the encoder power supply.
Encoder Power(VDD) External Resistor R
+5V
0 Ω (None)
+12V
1.8kΩ
+24V
4.3kΩ
If=6mA max.
External Encoder / Driver
With line driver output
PCI-8134
A,B phase signals
Index signal
EA+,EB+,EZ+
EZ+
EA-, EB-, EZ-
EXGND
GND