composite synchronised analog ouputs

[viswa]

Hi all,

             My problem contains 3 steps.

1. I would like to generate two sine waveforms synchronously with different frequencies and amplitudes.  (Which i can do now)

2. Generating a analog output (square waveform) using external digital TTL trigger analog input again in sync. (Which i can do now) 

3. Now i want to add one of the sine waveform to the square waveform  and produce a composite analog waveform.

So first two tasks are running independtly with out error.

But to do 3 task i need to run task 1 and 2 simultaneously. I just designed a new vi which contains task 1 and 2 in it leading to task3 vi. but it gives and error. I have attached all of the vis and images to this message. if any body has idea please help me out!!!!!!!!!!!!!

I am using Labview 8.2 version and USB6229 DAQ card which has 4 AO's.

[Andrew McL]

Hi Viswa,

Thank you for contacting National Instruments. I assume that you want to just add two waveforms together and you're not trying to do anything complicated with sampling data. 

If you replace the build array block with an Add block, you should be able to do this. I have attached a piece of sample code that should show you in a bit more detail. 

If I have misunderstood you, please let me know and I shall try and help you out.

Many thanks,

[viswa]

Hi Andrew,

                       I modified the programme for obtataining outputs from three analog output channels along with external digital trigger and analog input on USB 6229. The programme generates 3 output what i want is 2 synchronised sine waveforms and an analog square waveform

Now the programme is working and is attached to this post.

Now the difficulty is controlling sampling rate. For 2 sync  sine waveforms 100000 sampes per sec is needed because we need waveforms upto few tens of kilohertz range.

At the same time we need to generate a 25Hz square waveform which needs just few thousands of samples per sec.

Is it possible to over come this problem by any other method? 

[viswa]

I got error-89137 message when i executed the third vi in the first post. How can i resolve it?

Because of this error i tried to put all three channels in one task, which was attached in my first reply (http://forums.ni.com/ni/attachments/ni/250/53104/1/Three%20analog%20waveforms%20generation.vi).

Any help woul dbe greatly appreciated.

Message Edited by viswa on 10-27-2009 02:10 PM

Message Edited by viswa on 10-27-2009 02:10 PM