Generating 4 analog output waveforms with different frequencies

[viswa]

Hi John,

                  The vi has been modified according to you suggestions. Now it is generating AO and DO in sync!!!. There might be few modifications required in future, if i have any questions i will post back them in this thread. 

Thanks a million!!!

Regards

Viswa

[viswa]

Hi John,

                 I want to control each waveform parameters such as frequency, amplitude and phase independently, i can do that using numeric controllers. But i want to change frequency and amplitude while vi is running so i tried to use control KNOB instead of numeric control. The problem i cant control data range independtly for each of the elements. Could it be possible to implement it? 

What i mean is that i want to have variable control knobs with different maximum and minimum values for all parameters in every array.  

Suppose i want to have frequency for two waveforms say maximum to 10000Hz can be variable in steps of 100, where as  for other waveform i want to have maximum frequency 50 only and can be varible precisely in steps of 1.

[Dennis_Knutson]

There is no difference between a knob and any other numeric control. To set the range and increment, right click on the control and select Data Entry. Uncheck the 'Use Default Limits' and set the min/max/increment to whatever you want. You can also set these with property nodes.

[viswa]

Hi Dennis,

                         I did try the method that you are explaining but if you look at the vi attached in the previous page ver 2.0 you might get what i am trying to explain. If i change max and min value to any one of the knob control, all other knobs get the same settings. I just dont want that to happen.

Thanks for your quick reply.

[Dennis_Knutson]

I don't see any VI with knobs - just some image. In any case, there was a bug in earlier versions of LabVIEW where the property page for onc control appeared for all. This bug has been fixed. I don't remember exactly but I think the work around was to use property nodes.

[John_P1]

First of all, whether the control is a knob or a text field you can still change it on-the-fly.

It sounds like you prefer the knob (which is OK), but you want to have different max/min values on the different knobs.  The problem is that the control is an array of knobs (each element in the array is a cluster with the desired waveform parameters--the idea was that this would be scalable to any number of AO channels).  I don't know of a good way to change the scale of knobs in an array element-by-element.

If you want to have different knob scales for the different channels, I would probably use a cluster control for each rather than having one array of clusters.

Best Regards,

[Dennis_Knutson]

Ah, I missed seeing that the image was an array of controls. Sorry about the confusion.

[John_P1]

I had a feeling, it's hard to tell sometimes from a screenshot (it helps that I wrote the code in the first place).  Thanks for posting anyway!

[viswa]

Hello John,

                    You are right about using cluster of waveform parameters individually for each waveform than using array of waveforms.  I have modified the vi with my requiremnets and worked well, only the remaining thins is to implement triggering at rising or falling edge. Iknnow that its straight forward to implement. 

I never understood the link https://forums.ni.com/t5/Example-Code/Two-Analog-Output-Waveforms-With-Different-Frequencies-and-or/...

I had always a question about  multiple waveform generation. Does my task need to define any buffer lengths as explained in the above link?? 

Thanks for the help!!

I guess you have the sub vi Generate PWM.vi

Message Edited by viswa on 03-18-2010 06:59 PM

[cassio]

Hello,
I would like to use my DAQ 600USB to measure the resistance wires. You have an example VI?
Thanks