NI USB 6008 Can be used for simultaneous generating and acquiring signal

[Rayan IJ]

Hello guys

I am new in Labview town, and I am learning the Labview only by watching the video tutorial uploaded by NI. In Generating Signal episode they used a USB data acquisition device but I just have the NI USB 6008 device and I wanted to simulate the stuff they doing in the video only with this tiny toy. Is it possible to simultaneously generate a, for instance a sin wave and acquire it just only with use of this NI USB 6008 Device and nothing else.  I attached a photo here the way I wired up the analog channels. Can anyone please give me some hint to understand this?

Thanks

[charlesy]

Hello Rayan,

Your wiring connection is fine, but be advised that the USB-6008 does not support waveform analog outputs. This means you have to write each voltage output individually, for example in a loop. Take a look at the "Gen Voltage Update.vi" example. You could wrap a While loop around the DAQmx Write subVI, but you'll need some substantial delay in the loop for it to look repeatable.

USB has pretty high latency and is not deterministic, so it can get delayed by processing on your host computer. I'd expect tens of milliseconds of latency and uncertainty for each update. If you are just trying for something slow, like a 1 Hz sine wave, and you don't care about distortion, you could probably get a reasonable approximation with this device. It's really more intended for DC output levels.

By contrast, most other DAQ devices have an onboard memory where you download an entire waveform that is then fed to the D/A converter at regular intervals. That way, the hardware timing is completely independent of bus latency and processing overhead.

Hope this helps,

Charles