Chapter 5 Signal Connections
© National Instruments Corporation 5-11 NI 7350 User Manual
The polarity of the trigger (position capture) input is programmable in
software as active low, or active high, rising edge orfalling edge. You
also can use a trigger (position capture) input as a latching
general-purpose digital input by simply ignoring the captured position.
•Shutdown Input—When enabled in software, the shutdown input
signal can be used to kill all motion by asserting the controller inhibits,
setting the analog outputs to 0 V, and stopping any stepper pulse
generation. To activate shutdown, the signal must transition from a
lowto high state.
•Breakpoint <1..8>—You can program a breakpoint (position
compare) output to transition when the associated encoder value
equals the breakpoint (position compare) position. You can use a
breakpoint (position compare) output to directly control actuators or as
a trigger to synchronize data acquisition or other functions in the
motion control system.
You can program breakpoints as either absolute, relative, periodic, or
buffered positions. Breakpoint (position compare) outputs can be
preset to a known state so that the transition when the breakpoint
(position compare) occurs can be low to high, high to low, toggle, or
pulse.
You can set the breakpoint (position compare) outputs to Totem Pole
mode or Open Collector mode. In Totem Pole mode, the output buffer
can both sink and source current, which is appropriate for most
applications. In Open Collector mode, the output buffer can only sink
current. By default, breakpoint (position compare) outputs are set to
Totem Pole mode.
You can directly set and reset breakpoint (position compare) outputs to
use them as general-purpose digital outputs.
Wiring Concerns
Caution Keep trigger (position capture) input, shutdown input, and breakpoint (position
compare) output signals and their ground connections wired separately from the motor
drive/amplifier signal and encoder signal connections. Wiring these signals near each other
can cause faulty operation.
Caution Excessive input voltages can cause erroneous operation and/or component
failure.