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National Instruments Corporation
7
UMI Accessory User Guide — UMI-7764
Power for the encoders is internally routed from the power input terminal
block and is available on the +5 V terminal on each axis motion I/O
terminal block. You must supply a +5 V source to the power input terminal
block for proper operation. Refer to Figures 1 and 2 to help you locate the
encoder terminals on your UMI-7764 accessory. Figure 4 shows the wiring
for a differential encoder.
Note
The dotted loop indicates a shielded cable.
Figure 4.
Differential Encoder Wiring
Figure 5 shows the wiring for the single-ended encoder.
Figure 5.
Single-Ended Encoder Wiring
The UMI-7764 accessory allows for differential inputs for Phase A,
Phase B, and Index signals. You can easily accommodate encoders with
phase relationships different from Figure 6 by swapping the signals as
required by the specific application. The Index pulse must occur when both
Phase A and Phase B signals are logic low as shown in Figure 6. Servo and
closed-loop stepper applications require encoder feedback and consistent
directional polarity between the motor and encoder for stable operation.
The UMI-7764 uses the following standards for motor direction:
•
Positive = forward = Clockwise (CW) facing motor shaft
•
Negative = reverse = Counter-clockwise (CCW) facing motor shaft
Phase A
Phase B
Phase B
Index
Index
Phase A
Shield
1
1Connect to Digital Ground
Phase A
Phase B
Index
Shield
1
1Connect to Digital Ground
Summary of Contents for UMI-4A
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