How to do high speed data acquisitioning in real time using LabVIEW 7.0?

[Sub 148]

Firstly I'm a newbie to Labview. Secondly, to give a general background on my project, I'm trying to test the limits of a simple stepper motor. I've created a basic Labview program to step the motor and to get data under user defined conditions, but my time step is erratic--inconsistently jumping around and oftentimes creating a slight lapse. What I want to do is get as many data points as possible in the quickest time, but how? I was sampling at about 10 ms and was wondering if there was a way to sample any faster with a consistent time step?

Thank you and have a nice day,

Keith Blackwell

[CoastalMaineBird]

The LabVIEW DATA ACQUISITION HANDBOOK (not sure of the exact title), has examples of simultaneous I/O, which is what I assume you need.

Clock- controlled analog output (to drive the stepper), and analog input (to read your inputs), sound like the ticket for you.

You could load the output buffer with a pattern that drives your stepper, and get multiple input samples for every step, all precisely timed.

[Bill B]

Hello Keith,

If you would like to acquire a data point every 10ms, then you essentially need to be sampling your signal at a rate of 100Hz. This can easy be achieved, by doing a hardware timed acquisition. There are many example programs that ship with LabVIEW which demonstrate how to achieve this task. Follow this path to find one such example program in LabVIEW:

Help >> Find Examples >> Hardware Input and Output >> DAQmx >> Analog Measurements >> Voltage >> Acq&Graph Voltage-Int Clk.vi

This example will demonstrate how to do a hardware timed buffered input. Simply connect your signals and specify your sample rate and run.

Regards,
Bill B
Applications Engineer
National Instruments