Analog Output USB X 6361

[bryce2727]

I am a beginner to NI hardware. Thank you in advance for your time. 

I am trying to generate a 1MHz square wave with the 6361 using DAQmx. I notice that when I change "samples to write" the frequency changes. and when I change "rate" the frequency also changes..

I was not able to generate a frequency of 1MHz without receiving an error

"onboard device memory underflow. .....

Reduce your sample rate or try using DMA or USB Bulk."

I am incorrect to understand that the 6361 is capable of generating 1MHz frequencies?

[BrinkHombre]

Hey bryce2727,

Can you specify what your samples to write and rate inputs are for your DAQmx task? Also, can you provide a screen shot of your block diagram or the specific error code you are receiving? These will be helpful in further troubleshooting.

Here are a few articles that explain similar "underflow" errors with other DAQ devices. I believe they will give more context into why you are seeing this error, even though the AO frequency is specified in the NI-6361 spec sheet.

1. My PXIe-6124 Unable to Reach Maximum AO Rate
   • Analog Output Regeneration is our recommended method when generating periodic signals
2. Overwrite, Overflow, and Underflow Errors with Traditional NI-DAQ

Based on my current understanding, while you could be asking the DAQ device to write a waveform at an output frequency that meets the NI hardware's specifications, it is possible your computer's onboard FIFO is not being filled fast enough to keep up with the DAC sampling rate. The articles above provide some good places to start with how to fix this problem.

Best regards,