PSU output decay measurement (0.2ms) using USB 6229. Feasible?

[Gravey]

Hi Guys

I'm a Newbie so please forgive any lapses in protocol. I'm using a USB-6229 in a custom made end of line PCB tester. One test requires measuring the time taken from the start of decay of the UUT's onboard 3V3 supply to when it reaches 3.0V after switch off, typically 0.2ms. Given latency issues etc is it feasible to achieve this using the USB-6229's resources and Labview or should I design an external level change detection/comparator circuit to gate a counter on the DAQ board? Your input will be appreciated.

[Speedy_Badger]

Hello Gravey,

Welcome to the world of LabVIEW and DAQmx. If you are attempting to measure a change in time on the order of 0.2 ms (5 kHz) you should probably acquire at 10 times that rate to achieve a solid shape. This would mean you will sample at 50 kHz. The USB 6229 is capable of 250 kHz on a single input channel (or 250 kHz aggregate on multiple channels) which is roughly 5 times the sample rate you need. This being the case I would say that the 6229 is more than capable of measuring your application without the effect of latency.

Since this is your first time using LabVIEW and DAQmx I would suggest looking at the following resources. They are great starting points on the tools available.

Getting Started with NI-DAQmx

Learn 10 Functions in NI-DAQmx and Handle 80 Percent of Your Data Acquisition Applications

How can I learn LabVIEW

Regards,