MID-7604/7602 Stepper Power Motor Drive User Guide
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When connecting the encoder wiring to your MID-7604/7602, use shielded wire of at least 24 AWG.
Analog noise filters filter the encoder inputs in the MID-7604/7602. You must use cables with twisted
pairs and an overall shield for improved noise immunity and enhanced encoder signal integrity. Figure 9
shows twisted pairs in a shielded cable.
Figure 9.
Shielded Twisted Pairs
Note
If you use an unshielded cable, noise can corrupt the encoder signals, resulting in lost counts,
reduced accuracy, and other erroneous encoder and controller operation.
Limit Switch Terminal Blocks
For end-of-travel limit, home, inhibit input, and inhibit output connections, MID-7604/7602 axes have
a separate, 6-position removable screw terminal connector block. Figure 10 shows the limit switch
terminal block pin assignments.
Figure 10.
Limit Switch Terminal Block Pin Assignment
(Passive Limit Switch Connection Example)
The inhibit output signal is asserted low from the MID-7604/7602 when an axis is inhibited. This signal
can be useful for actuating mechanical brakes or for monitoring an axis status. An axis is inhibited if the
host bus interlock circuitry is activated, if the ENABLE switch on the front panel is in the inhibit
position, if the motion controller’s inhibit signal is low, or if the per-axis inhibit input is actively driven.
The MID-7604/7602 stepper drive remains in a reset state for 500 ms after the inhibit is deasserted.
Therefore, you can lose steps if you attempt to issue a start motion command within 500 ms from the
deassertion of the stepper drive inhibit. A Kill command asserts the inhibit signal from the controller
and a Halt command deasserts the inhibit signal from the controller. The yellow LEDs (middle row) and
red LEDs (top row) on the front panel illuminate if an axis is currently inhibited (killed state).
S
hield
+5 V
Encoder Index
Encoder Index
Encoder B
Encoder B
Encoder A
Dr
a
in
Encoder A
Digit
a
l
Gro
u
nd
1
6
2
3
4
5
Forward Limit
Home Input
Inhibit Input
Digital Ground
Reverse Limit
Inhibit Output
