Breakpoint VIs

NI-Motion VI

Breakpoint VIs

Position breakpoints are an enhancement to the encoder decoders on the NI motion controller and are available when the encoders operate as axis feedback or as independent encoder resources. Breakpoint functionality is available on servo and closed-loop stepper axes. You can use Breakpoint VIs to configure, enable, and read the position breakpoint status. Advanced VIs, such as periodic breakpoint and buffered breakpoint can be used to achieve higher-frequency breakpoints. To configure buffers for buffered breakpoints, refer to Buffer VIs. You also can load a breakpoint position modulus. Like all motion I/O, breakpoint outputs also can function as general-purpose outputs with the Set Breakpoint Output MOMO VI.

Note  All breakpoints can be affected by jitter in the motion system. For example, if you have breakpoint positions very close to each other, the jitter in the motion system could cause the position to change enough to reach the breakpoint when a breakpoint is not intended. Increase the value of the breakpoint window using Set u32 to compensate for system jitter.

Refer to the following table for the maximum breakpoint rates for each type of breakpoint. Not all breakpoints are available on all controllers.

Breakpoint Type Maximum Frequency
Single 150 Hz
Buffered, PID rate of
62.5 µs to 250 µs
2 kHz
Buffered, PID rate greater
than 250 µs
1 kHz
Periodic 4 MHz


Click the icons for VI descriptions.

Load Breakpoint Position Load Breakpoint Modulus Configure Breakpoint Enable Breakpoint Output Set Breakpoint Output MOMO Read Breakpoint Status Configure Breakpoint Output Up to Owning Palette

Configure Breakpoint

Load Breakpoint Position

Enable Breakpoint Output

Read Breakpoint Status

Configure Breakpoint Output

Set Breakpoint Output MOMO

Load Breakpoint Modulus