Analog Output Express VI myRIO

[Eng.Fel]

Spoiler

Hello,

I started to work with Labview few month ago and I liked it. It is very intuitive!

So, some weeks ago I got the NI myRIO. But, now, I am having trouble with the analog output express VI.

I add a control in the express VI and measured with a voltimeter the output and I realized that it just send a pulse, but I need that it send a flat signal.

I wasn't able to find a way to change it. 

Does anyone know how to change it? Or have a tip what can I do to make this a continuous flat signal?

Thanks

[j_bou]

Hello Eng.Fel,

How are you using the express VI? Is it in a loop? Please feel free to post your code to the forums so we can assist you further.

In addition, refer to the help document below for details regarding this express VI. As the document below recommends, you can use the High Frequency Sampling.lvproj in the labview\examples\myRIO\High Frequency Sampling directory to get stated with the Analog Output express VI.

Analog Output Express VI:
http://zone.ni.com/reference/en-XX/help/373925B-01/myrioreference/myrioref_exp_ao/

Regards,

j_bou

[Eng.Fel]

Hi  j_bou,

Thanks for the help.

Yes, I am using it inside the main loop of myRIO and I am just able to read some voltage in the voltmeter when in the Labview the value of the wire connected to the analog output express VI changes, otherwise the value that i read in the voltmeter is zero. 

I uploaded the Vi that I am using to test the analog output of myRIO. In my real application Instead of a control connecting the express VI I have a shared variable that is calculated in a VI in the desktop. Basically, I just need that myRIO send a proportional output signal between 0-10V.

My knowledge from electronic is very basic, maybe I am having this trouble because I am interpreting this VI wrong. I am using the express analog output VI and I thought that doing it, I would have a DC current output with the value that Express VI was receivingin the code.

What I couldn't understand about that material in the link is about the frequency and 1 or n samples. Is it meaning that the output is AC instead of DC? Also I didn't find how to change the express Vi from 1 sample to n sample in the Labview.

Thanks

[Eng.Fel]

I also tried to simulate a DC signal and link it to the analog output express VI from myRIO but I still just can measure something in the voltmeter in the instant that I change te value of the offset after it back to zero. It does not make sense for me...

Please if some one can indicate me material or directions to send a constant output from 0-10 V in myRIO, please share it.

Thanks

[j_bou]

Hello Eng.Fel,

I slightly modified the High Frequency Sampling.lvproj example project (mentioed in my last post) to output a constant instead of a sin wave. I read the outputted signal back into the myRIO using a AI channel. Using the code below, I could output a contact DC voltage and read it back in. Take a look at the code and let me know what you think.

j_bou

[Eng.Fel]

Hi j_bou,

Thanks for reply!

I wasn't able to make it work in my Labview.

When I loaded the files it search for a file called "myRIO v1.1 FPGA Throughput". I couldn't find it so I loaded ignoring it and the VI shows the running arrow broken. Looking for the error it is related with a bitfile in the myRIO. Do you know what is it?

I attached some pictures of the error.

PS: To open your files I needed to install a the FPGA module that I didn't have installed before.

Thanks you!

.