National Instruments Quadrature Input Module FP-QUAD-510 - Manual (Page 4)

FP-QUAD-510 4 www.ni.com
Figure 3. Basic Field Connections to Single-Ended Encoders
The FP-QUAD-510 supports differential inputs for Phase A,
Phase B, and Index signals. You can easily accommodate encoders
with various phase relationships by swapping the signals and/or
connecting them to the inverting inputs as specific applications
require.
The Index signal must occur when both the Phase A and Phase B
signals are low, as shown in Figure 4. If the index polarity is
inverted, try reversing the +Index and –Index signals on differential
encoders or using the –Index input on single-ended encoders.
Figure 4. Encoder Signal Phasing
Table 1 lists the terminal assignments for the signals of each axis.
+A and –A represent the Phase A signals, +B and –B represent the
Phase B signals, and +I and –I represent the Index signals.
+A
+B
+Index
+5 V
GND
Encoder
+5 V
Reg
+ –
+A
–A
+B
–B
+I
–I
NC
NC
NC
V
sup
COM
V C
Phase A
Phase B
Index