USB-6281 arbitrary analog output

[F11Raven]

Hello, I am very new to LabView and national instruments. I'm trying to output a sine wave with noise with my usb-6281. I cant find how to do this in labview 8.2. I see how to output a normal sine wave from signal express and the measuremtn & automation explorer but I would like to make a program in labview to execute it. and not only a sine wave but one with noise. Can anyone point me in the right direction for this? is this even possible with the 6281? I should also probably mention that a sine wave is not really necessary, I am controlling a voltage variable attenuator and wish to change the attenuation maybe 5 times a second so speed is not essential. I could even run it through a script of voltage levels. but I'm not sure how to do that either. thanks in advance for your help.

[P.Sanders]

I believe you may need NI-FGEN VI's. See this example which changes an arbitray waveform on the fly in LabVIEW, best of luck! 🙂

[Dennis_Knutson]

p. sanders,

NI-FGEN is only for the Function Generators, not an M-Series DAQ Card.

F11Raven,

Just open the Express VI called Simulate Signal. It has a 'Add noise' option. If you want to use lower level functions, use the search button on the functions palette to find all of the noise functions.

[F11Raven]

Thanks for the replies guys. Ok so now i have the signal, how do i output it to the hardware? when i tried to use the instrument IO assistant it said i can only communicate with the serial, Ethernet, or GPIB interface. I need to output on the USB.

[Dennis_Knutson]

Why would you think you need to use the Instrument I/O Assistant? You said you have a USB-6281. That means you need to use DAQmx and the DAQ Assistant. This is the same thing you used in signal Express.

[F11Raven]

I was using an evaluation version of labview 2009 and i saw the Daq assistant but im using labview 8.2.1 now and i cant find it.

[Dennis_Knutson]

It's included with the installation of DAQmx. If you have the Measurement I/O palette and the DAQmx functions, you could try a repair. Otherwise, just do reinstall.

[BROhan · Accepted solution]

Hi F11Raven,

The DAQ Assistant is bundled with DAQmx, which is the driver necessary to interact with your USB-6251. You can download the latest version of DAQmx here. After installing it, you should be able to use the DAQ Assistant within LabVIEW.

[F11Raven]

i have no DAQ anything in the measurment I/O pallete. Il try a reinstal and see if that works

[F11Raven]

OK i installed the DAQ thing the BRO said and now it works thanks alot!