OMEGA OMB-DAQ 2408 Data Acquisition Issue

[Eli32]

I am having trouble working with data acquisition in LabView. I am using an OMEGA OMB-DAQ 2048 data acquisition board (manual attached) to acquire 2 voltage signals. I have configured the board to acquire data at 1000 samples per second. I am using a sub-vi (attached) to acquire the data. The sub-vi requires input of a sampling rate and number of samples per channel. However, none of the settings I am using seem to match with the actual data acquisition rate I am getting in LabView (which is very low and produces choppy data). I have played around with changing settings in both the sub-vi and the board and have been unsuccessful in figuring anything out. The settings seen in the screenshot provided seem to work the best. I have used a different program (TracerDAQ) to test the board and the computer. The data acquisition in this program works perfectly fine, so I figure I have a setting wrong somewhere in LabView. How do I get LabView to acquire data at the rate I would like it to using this data acquisition board? I've included a screenshot of my program while it is running and a file of data acquired during that same run. 

[GerdW]

Hi Eli,

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@Eli32 wrote:

I am using an OMEGA OMB-DAQ 2048 data acquisition board (manual attached) to acquire 2 voltage signals. I have configured the board to acquire data at 1000 samples per second.

...

The data acquisition in this program works perfectly fine, so I figure I have a setting wrong somewhere in LabView. How do I get LabView to acquire data at the rate I would like it to using this data acquisition board?

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You don't have a "wrong setting", but a completely wrong approach!

Currently you do this:

1. initializing a DAQ task
2. setting several parameters of that task, including samplerate
3. reading just a single sample (!)
4. clearing/closing/finishing this task
5. start over with step 1

Can you see the error in those steps?

Initializing/parametrizing a task takes its time, cleaning up that task too: all that work/time just to read one single sample?

Please try again, but implement these steps:

1. initialize a DAQ task
2. set all parameters, including samplerate
3. read 100 samples
4. repeat step 3 until error or measurement finished
5. clear the task

This is how most DAQmx example VIs do the job: it is also advised to learn from example VIs coming with LabVIEW...

[Eli32]

Thank you GerdW,

I am using the examples you pointed to and it is working a lot better, however I am struggling to figure out how to acquire data from more than one channel at the same time. Here is the sample program I am using.

Thank you for you help,

Eli