labview interfacing with labjack

[paulrobinson]

Hi all,

       I'm interfacing labjack U3 series to acquire analog signals at the defined sampling rate and i able to acquire the signal for first 8 channels but when i set it up above 8 channels i'm not able to receive the data and one more confusion here is 'how to set differential and single ended mode in this case?', here i have attached my vi and give me some suggestions thank you bcoz i'm never get used to this labjack before.

Thanks in advance,

Regards,

Paul 

[David_L]

I don't really know LabJack, but there is a third party tool available for interfacing with this hardware.  You may consider it instead of reinventing the wheel.

http://sine.ni.com/nips/cds/view/p/lang/en/nid/211373

--David_L, CLA

[LabJackSupport]

Our LabVIEW support for the U3 is on the following page, but I'm guessing you already found that:

https://labjack.com/support/software/examples/ud/labview

Are you using command-response mode, or stream mode?

https://labjack.com/support/datasheets/u3/operation

We can't open your attached VI because the version is too new, but if you post a screenshot we can see what you are doing.

If you are using command-response mode and don't need top performance, you could just make a call to eAIN to get a reading for each channel.  Something like "U3 Efunction Loop Example.vi", but with a bunch of calls just to eAIN rather than the other easy functions.

If you are using command-response mode and want top performance, "U3 Multiple IO Example Loop.vi" is a good example of the general technique you want to use.

If you are using stream mode, look at "U3 easy Stream Example Full.vi".

You control single-ended or differential by what you specify for the negative channel.  Use 31 or 199 for single-ended, or use the desired negative channel for differential:

https://labjack.com/support/datasheets/u3/hardware-description/ain/channel_numbers

https://labjack.com/support/app-notes/differential-analog-inputs