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Trouble Using USB-6009 w/MATLAB Data Acquisition Toolbox and NI-DAQmx



I am currently trying to perform both analog output and analog input using the NI-DAQmx drivers for the MATLAB Data Acquisition Toolbox. However, it seems that it is very slow. We need to be able to output a sine wave, then measure a voltage at a speed of around 100Hz. However, when I use outputSingleScan and then inputSingleScan, the best it seems to do is about 40 Hz. 


If I just do the outputSingleScan without the inputSingleScan, it looks like it can achieve 1 kHz. I assume that it is the successive calls cause the slowdown. Is this a limitation with the hardware? Or, is it a limitation because we are using MATLAB? Would we be able to achieve the speeds we need with the USB-6009 if we were using C? Or, would it require different hardware?


Any information would be useful.



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Hello, Nyamaekye,


I checked the NI USB-6009 User Guide and the maximum AI sample rate is 48 kS/s. According to this, you can use the sample rate you mentioned. Analog inputs and outputs are independent processes, so there shouldn't be a hardware limitation. What could be happening is a limitation when implementing the software, because the hardware does allow it.


You can verify this with community examples (I'm linking some below):


How to acquire and generate data using NI DAQ simultaneously on a continuous basis


Acquire Data Using NI Devices

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