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Inhibit output signals can be activated automatically upon a shutdown condition, a Kill
Motion command, or any motion error that causes a kill motion condition, such as
following error trip. You can also directly control the inhibit output signals to enable or
disable a driver or amplifier.
Step, Direction, and Inhibit Output Circuit
The NI 7340 motion controller provides single-ended step, direction, and inhibit output signals.
To connect the NI 7340 to drives with opto-isolated inputs, connect as shown in Figure 4-2. If
the optocoupler does not include its own current-limiting resistor, you must provide an external
resistor in series with the NI 7340 output, as shown.
Caution
resistor that limits the current to a value below the maximum specifications of the
controller and other hardware.
Figure 4-2. Step, Direction, and Inhibit Output Circuit
3.3 kΩ
Limit and Home Inputs
The following signals control limit and home inputs.
•
Axis <1..4> Forward Limit Input
•
Axis <1..4> Home Input
•
Axis <1..4> Reverse Limit Input
These inputs are typically connected to limit switches located at physical ends of travel and/or
at a specific home position. Limit and home inputs can be software enabled or disabled at any
time. When enabled, an active transition on a limit or home input causes a full torque halt stop
of the associated motor axis. In addition, an active forward or reverse limit input impedes future
commanded motion in that direction for as long as the signal is active.
Note
By default, limit and home inputs are digitally filtered and must remain active
for at least 1 ms to be recognized. You can use MAX to disable digital filtering for
limit and home inputs. Active signals should remain active to prevent motion from
proceeding further into the limit. Pulsed limit signals stop motion, but they do not
prevent further motion in that direction if another move is started.
To prevent damange to the NI 7340 or other motion hardware, use a
NI 7330
+5 V
Step/Dir
Optional
NI 7340 User Manual and Specifications
Drive
+5 V
Step+/Dir+
Step–/Dir–
© National Instruments | 4-5
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