Hello.
Unfortunately, we do not have any specific examples for controlling the jrk via LabVIEW. However, one of our customers posted a VI for the Maestro Servo Controller, which uses very similar TTL Serial commands, so you should be able to use that as a starting point. You can see the supported serial commands in the "Motor Control Commands, Error Reporting Commands, and Variable Reading Commands sections of the jrk’s user’s guide. Also, please note that your jrk’s serial mode should be set to USB Dual Port.
Brandon