DAQ

[SBk]

Hello

I have an external voltage trigger and I want to use it in my labview program, which measure data through serial port and save it on the text file. I plan to add another column on the text file to show the status of voltage either zero or 5 volt.

I already tried to use DAQ Assistant. I couldn't figure out how can I connect the data pin to the spread sheet. Right now my data is saved on the text file using Concatenate string since they are string. But what is the type of data (Number, String,..)?

I studies several tutorial from Labview Help, such as Read Dig Chan, or Cont Aqc and Graph,... Over there mostly used DAQmx create channel and DAQmx create timing. IS it really necessary for this application?

I appreciate any help or idea;

Best

[SBk]

To complete my previous question: when I trigger external voltgae, I would like that DAQ start working. I  figured out how to save the out put of DAQ but it dosn't start when I turn on the trigger switch.

[MoReese]

I assume your VI is a sub-vi.  This one attached is within a while loop.  The data will record properly to the text file.  Did you intend to use the Number to Decimal String function?  I changed it to Number to Fractional String.  You will need to change the Simulate Signal Xpress VI back to a DAQ Assistant.  I hope this helps.

[MoReese]

Sorry, here's the VI.

[SBk]

Thanks for the reply. I cannot test yours right now, but I have a question from it. So if I changed the simulate signal to DAQ assitant, what was the reason that you used it? And how can u trigger the program to start with the external voltage?

Cheers;

[GITA_A]

Hi,

 DAQ Assistant is used when you have a hardware and to acquire signal form it. If you dont have any hardware you can simulate different signals like sine, triangle etc using Simulate Signal express vi. And for your program to execute in response to a trigger program it using DAQmx vi's as you have seen in examples.

[MoReese · Accepted solution]

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@SBk wrote:

Thanks for the reply. I cannot test yours right now, but I have a question from it. So if I changed the simulate signal to DAQ assitant, what was the reason that you used it? And how can u trigger the program to start with the external voltage?

Cheers;

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The reason I used it, as GITA has eluded to, was because I don't have any hardware that can generate a signal, that's why I simulated one.  You can trigger a start by determinig what voltage constitutes a start condition, doing some comparison, and then trigger with a boolean function.

[SBk]

Thanks Guys for all the useful info.:)