data acquisition

[hanskoh86]

Hi everybody,

I try to built a simple acquisition program by using labview 8.5.1 and DAQ card is NI USB 6009.

After i connect it with a  AC 240V 60Hz step down to 6V 60Hz circuit, it should screen out with in sinusoidal waveform. But now, it only able to screen out in nearly square waveform. it seen aliasing happen. But i try a lot of method to configure, but still the same. Can someone help me to checking what wrong with my code and configure?

Another question is what is the mean of number of sample per channel? i try to configure the DAQmx read to single channel --> single sample --> DBL but it error since i on  need one sample only.

Saying to thank you to anyone which can help me to solve my problem. Thank You.

[jaraalmonte]

Please attach your program as a vi for help (from me at least). Number of samples per channel is the number of data points your program will aquire each time you call a read vi. For example, if you set your frequency to say 1kHz, then if you ask for two samples (starting at time 0) you will get the value at time t=1ms and t=2ms returned in an array.

[hanskoh86]

Hi,

This is the vi attachment. Thank you for your explaination. 

[hanskoh86]

For actual program, i need to continue taking the value from start until i stop the program. So what should i configure so to make sure it wil happen beside configure the number of sample? 

[Meadow]

Hans,

You will need to add several thing. Play and timing would be needed so that your acquisition doesn't run too fast.

I have made some adjustment to your original VI and it is attached below. 

One thing to add, You can try the examples in the LabVIEW as a base to learn on how to do data acquisition. Simple continous acquisition until complex synchronized start of acquisition and generation are available in the LabVIEW Daqmx example code.

Hope this helps.

James G

[hanskoh86]

Hi Meado,

Thank You for your assist.

[Meadow]

Hans,

Do kudo or solved if it solves your problem.

James

[hanskoh86]

Hi,

I founf another proble. The problem as per attach.

How could i solve the problem in order to open up the AI.vi

[Meadow]

Hans,

Just say that it was saved from later version than what you have.

Attached is saved for LabVIEW 8.5

Regards,

James