USB 6211 outputs Voltage

[daisy_11]

Hi,I have encountered such a problem that after using 6211 for a period of time, a 3.3V constant voltage is output after 6211 is connected to the computer. After 6211 is output voltage controlled by the program, the sine wave displayed by the oscilloscope is not complete, only the positive semi-axis waveform

[GerdW]

Hi Daisy,

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@daisy_11 wrote:
I have encountered such a problem that after using 6211 for a period of time…

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And what have you done to understand/prevent that problem?

What is a "period of time"? Seconds, minutes, hours, days?

What changes when that "period of time" has elapsed?

Does the DAQ device (and whatever is connected to that device) work as expected before the "period of time" has elapsed?

What is connected to your DAQ device?

[daisy_11]

6211 was connected to the computer and the output end was connected to the oscilloscope. I wrote the data into DAQmx, and the output voltage and oscilloscope showed waveform, which showed no problem. After testing for one or two days, the voltage waveform of 6211 output the same data appeared problem, and 6211 output constant 3.3V voltage

[GerdW]

Hi Daisy,

what happens when you use another AO channel?

What happens when you use a simple handheld DMM to measure the output of the USB6211?

(Is the USB6211 still ok or did there happen some voltage spike damaging your DAQ device?)

[daisy_11]

The other channel is not used, but when the output end is measured with a multimeter, Ao0 is 3.3V and Ao1 is 2V

[GerdW]

Hi Daisy,

does your test work as expected when you use AO1 instead of AO0?

When the answer is "yes" then there might be a hardware problem with AO0…

[daisy_11]

Two channels have just been tested, both of which output the wrong waveform, where AO1 was not used before

[Kevin_Price]

Please post your code *and* the waveform data you're writing to the task.

In the case of the Finite Sampling code screenshot, the last sample in that Waveform global will be held indefinitely after you stop the task.  That's the nature of AO on M-series devices, they maintain their last value.  Is it possible that the last waveform value is 3.3V?

In the case of the Continuous Sampling code screenshot, it isn't clear when the task will be stopped.  It seems unlikely that it'd always get stopped at the same sample #, but I also don't know how your data values vary with sample #.

Code and data will help clear that up.

-Kevin P

[daisy_11]

The program stops the task and resets the device after the stop button is pressed The final voltage in a finite sample is 0V instead of 3.3V Thank you for your reply. I contacted the supplier and learned that this problem was caused by the hardware damage of 6211

[GerdW]

Hi Daisy,

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@daisy_11 wrote:
I contacted the supplier and learned that this problem was caused by the hardware damage of 6211

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You might think about implementing a buffer/protection circuit to prevent other hardware damages of your DAQ devices…