Using Onboard Programs with the NI SoftMotion Controller

To use onboard programs with the NI SoftMotion Controller, use the LabVIEW Real-Time Module (RT) to target your application to run in the same environment as the NI SoftMotion Controller.

Because the NI SoftMotion Controller onboard program shares the same processor and system resources with the NI SoftMotion Controller, ensure you consider the following points before running your application in LabVIEW RT:

• Ensure that your top level VI is configured to run at normal, above normal, or high priority. If you are targeting LabVIEW RT for ETS, use the timed loop instead of changing the priority of your top level VI.
• Follow the guidelines in the LabVIEW Real-Time Module User Manual. The guidelines regarding memory allocation and using shared resources are especially important.
• The jitter of the system increases with the number of devices used in your RT system. Enable only the devices you need to use for the current application.
• Because interrupts cause jitter, National Instruments recommends you configure your application to poll for data periodically rather than wait on an interrupt.

  You can further decrease the jitter under ETS by configuring the Ethernet mode to be polling. You configure these settings for the RT controller in Measurement & Automation Explorer (MAX).

  Under LabVIEW RT, the NI SoftMotion Controller runs in the background at time critical priority. The NI SoftMotion Controller is designed to consume less than 40% of the processor bandwidth. The rate at which the NI SoftMotion Controller updates its data is typically 100 Hz.