USB 6289

[Rsilva]

Hi folks!

This is my first post so I apologize if I am not doing something by the book.

I am new to LabVIEW (I am a Chemical Engineer) and I am trying to use (or code if you will) a Digital Signal Generator.

I have studied a bit on the subject and I am wondering if it is posssible to generate digital signals with LabVIEW using a binary counter....or something else, suggestions are

greatly aprecciated.

For this project I am using a USB-6289 DAQ Board. 

The purpose is generate a digital signal using LabVIEW and with the internal DAC of the USB-6289 output analog signals.

I have not code (sorry...like I said I am new to LabVIEW)...and I am still in the process of choosing a direction for the code...:smileywink:

So any suggestion or tip, for the code or in the digital signals subject, are appreciated.

Cheers :smileyhappy:

[Dennis_Knutson]

I don't understand why you would want to generate digital signals with the analog output. Why don't you use the digital outputs? Explain exactly what you mean by binary counter.  

Open the example finder (Help>Find Examples) and go to Hardware Input and Output>DAQmx>Digital Generation.

[Rsilva]

Yes Dennis you're correct, I meant output and not input! The digital signals are going to be sent to a signal generator module (and that one does the DAC function, if I am not mistaken)...

Like I said I am kinda new at LabVIEW and I have already checked the examples in the examples section.

However I want to know if it is possible to generate digitals signals using just LabVIEW codin, and if it is not too much trouble, some pointers are appreciated....since I am 

a chemical engineer, and electronics is not really my field of experties...

The digital counter comes from what I have read so far in terms of digital signal generation, I have seen terms like "numerically-controlled oscillator", "digital counter", "phase accumulator", "DDS generation", and sadly I have to admit it is a little bit confusing...

Hope I am not abusing the scope of the forum...

Thanks in advance for any help.

Cheers

Message Edited by Rsilva on 04-06-2009 12:44 PM

[Dennis_Knutson]

Things still do not make any sense to me. What kind of signal generator do you plan on using? What is the interface to the pc? What do you mean by generating digital signals by just using LabVIEW? Of course you can but if you need to output them, that is what the digital outputs of the 6289 are for.

[Rsilva]

Yes Dennis, and I used those digital output channels in the USB-6289 with the examples in LabVIEW.

However, I reached a point where I have some doubts (and for the sake of not complicating let me address just the LabVIEW coding part, if I may):

1) Using the "Write Dig Chan" example in LabVIEW, and wiring the digital channels of the 6289 to a Logic Analyzer, I can visualize the output signals but the signals are random...they do not maintain the "1" value.....or is this the intended purpose, to have random digital signals outputing?....

 2)And my main issue is how to code a digital signal generation (to output in the 6289) so I can change the settings (square, triangular, sinusoidal, and clock, etc)

Again, I appologize for the lack of experience, and I thank you for your patience.

Cheers.

[Dennis_Knutson]

I think we have a problem with language. You had talked about digital generation and I think you are just talking about generating some analog signals with the 6289 and not what is normally though of as 'digital generation'.

For outputing sine/square/triangle waveforms, look through some of the examples under DAQmx>Analog Generation>Voltage. One of the more simple ones is called Cont Gen Voltage Wfm-Int Clk.vi and allows you to output a particular waveform with selectable frequency and amplitude

[Rsilva]

Yes, I do believe so Dennis, and I appologize for it.

I'll try to make it simple and take it step by step:

1) Is it possible to output a digital signal with USB-6289 with adjustable frequency and amplitude.

I want to do this because it gives me a better control (using digital signals, that is....).

Thanks again.

Cheers

[Dennis_Knutson]

I am really confused as to what you want to do. Sometimes you talk about digital signals and sometimes analog. A digital signal is binary and cannot have different amplitudes. Maybe if you drew a picture of what you want to output from the DAQ card.