ADLINK PCI-8164 - Manual (Page 56)

44 Signal Connections
over driving the source. The differential signal pairs are converted
to digital signals EA, EB, and EZ, then feed to the PCL6045 ASIC.
Below are examples of input signal connection with an external
circuit. The input circuit may be connected to an encoder or motor
driver if it is equipped with a differential line driver or an open col-
lector output.
Connection to line driver output
To drive the card encoder input, the driver output must provide
at least 3.5V across the differential pairs with at least 6 mA
driving capacity. The grounds of both sides must be tied
together. The maximum frequency will be 4 Mhz or more
depending on the wiring distance and signal conditioning.
Connection to open collector output
You need an external power supply to connect with an open
collector output. Some motor drivers provide the power source.
The diagram below shows the connection between the card,
encoder, and the power supply. Note that an external current
limiting resistor R is necessary to protect the card’s input cir-
cuit. The following table lists the suggested resistor values
according to the encoder power supply.
I
f
= 6 mA max
Encoder Power (V) External Resistor R
+5V 0
Ω
(None)
+12V 1.8k
Ω
+24V 4.3k
Ω