National Instruments FP-QUAD-510 User Manual

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FP-QUAD-510
4
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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