MID-7604/7602 Stepper Power Motor Drive User Guide
14
ni.com
Use shielded, 20 AWG wire or larger for the motor power cable. If available, you should connect a case
ground wire to pin 3 (Ground/Shield) to avoid ground loops and signal noise problems. Case ground
connects to the motor housing, not to the motor power terminals.
The MID-7604/7602 contains bipolar chopper drivers. You must wire the stepper motors in a 4-wire
configuration as shown in Figure 4. You must isolate unused lead wires and leave them disconnected.
Refer to the
section of this guide for additional information on
connecting 6- and 8-wire motors and on the alternate half-coil configuration.
Caution
Never connect unused center taps or winding terminals to pin 3 (ground) or to each other.
Encoder Terminal Blocks
For quadrature incremental encoder signals, each MID-7604/7602 axis has a separate 8-position
removable screw terminal block. Where applicable, the MID-7604/7602 accepts two types of encoder
signal inputs: single-ended (TTL) or differential line driver. You can accommodate open-collector
output encoders by using 2.2 k
pullup resistors to +5 VDC.
Figure 5 shows the typical encoder wiring pin assignment for single-ended signal input.
Figure 5.
Typical Single-Ended Encoder Wiring Pin Assignment
Figure 6 shows the typical encoder wiring pin assignment for differential line driver signal inputs.
Figure 6.
Typical Differential Line Driver Encoder Wiring Pin Assignment
If the encoder cable length is greater than 3.05 m (10 ft), use encoders with line driver outputs for your
applications. Power for a +5 V encoder—generated by a power supply inside the MID-7604/7602—is
available on pin 7.
Note
If you require other encoder power voltages, reference an external power supply to the Digital
Ground signal on the 8-pin encoder terminal block.
1
2
3
4
5
6
7
8
Encoder A
Encoder B
Encoder Index
+5 V
Digital Ground
1
2
3
4
5
6
7
8
Encoder A
Encoder A
Encoder B
Encoder B
Encoder Index
Encoder Index
+5 V
Digit
a
l Gro
u
nd
