Hello Nick,
From your description, you are trying to get your Labview application to run at 5kHz. Unfortunately most Labview Vis, especially ones containing Express Vis, will not run at that rate. Most DAQ applications will have the data acquisition loop run at 10Hz. You can post a screenshot of your code if you want help evaluating it.
Eric
Eric Liauw
Senior AE Specialist - Automated Test | CLD | CTA
National Instruments