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NI845x, Vref control (0 (V) ~ Vref (V))

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I have problem while controlling NI NI8452, Vref voltage. When I plug in My USB device, "NI8452"

i) Vref =0V

ii) After ruing my VI (LabVIEW program), Vref= 3.3V (which is programed value)

iii) After stopping my VI, Vref is again 3.3V. (the value remain same, as programed)

To make Vref = 0V, i have to remove the USB and plugin gain.

Is there anyway that i can make Vref=0V, when i stopped my VI.

Any help would be appreciated.

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Did you have any problem, when Vref is 3.3V after communication?


I also experienced the same situation when communicating SPI.

But, I confirmed that the Vref operated well when the SPI communication is executed again. 


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Accepted by topic author fpk
06-24-2019 06:42 PM

I am using I2C, and have no issue in communication, when Vref=3.3V.


My main target is to Run VI @Vref=3.3V for sometime, then make Vref=0 (and stop the program for sometime) and again run VI with Vref=3.3V.

Like On/OFF the slave for intended period of time.

I found that I can make a state machine and control the USB using devcon, ""

Now i have the same issue, The program run well initially, after disable USB 8452 and again enable USB 8452 , I received communication error with the slave.



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