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National Instruments Corp.
19
NI 9505E Operating Instructions and Specifications
Figure 9.
Single-Ended Encoder Input Circuit
Closed-loop servo applications require consistent directional
polarity between the motor and encoder for correct operation.
One industry-standard directional polarity is as follows:
•
Positive = forward = clockwise (CW) facing motor shaft
•
Negative = reverse = counterclockwise (CCW) facing motor
shaft
Refer to Figure 7 for a depiction of clockwise and
counterclockwise rotation. If encoder counting does not behave as
expected, change the encoder polarity in the FPGA or swap the
Phase A and Phase B connections.
Receiver
Encoder
Signal
Encoder
Encoder
NI 9505E
No Connection
COM
COM
+5 V
+5 V