how to display the data in a multichannel task

[soundofwind]

The task is composed of reading data from 12 virtual channels, how can I display the real time data in these 12 channels separately after the DAMx read. I tried to use the Select Signals function in the Express. but that means i have to use 12 of them for all the channels. Is there a better way to do that? thanks

[Broken_Arrow]

Using DAQmx Read, click on the Read output and Create Indicator. That'll be an Array. Drag the array to the size (number of elements) you want to see, and that's it. Each element corresponds with each channel, in the order you added them to the task.

[soundofwind]

 thanks. What if i want to create individual indicators for each channel.

[soundofwind]

I tried to use the index array but i didn't know how to match each channel. are there any better ways?

[Dennis_Knutson]

If you leave the index inputs unwired, it will default to elements 0 through whatever, in order. That means you can clean all that up. You should also clean up all of the wires that are going every which way. I don't see why you have the indicators set to EXT data type and I don't understand why you are taking multiple samples (NSamp) and displaying only one value. Why use NSamp and throw most of the data away?

[soundofwind]

What should i do then if i want to indicate each channel continuously i mean real time? thanks

[Dennis_Knutson]

You are showing the data continuously. You have the option of displaying the data in a grpah, you can switch to single sample acquisition, yoo can specify the number of samples to be less than the entire scan. Define what you mean by 'real time' and you can get a more precise answer.

[Broken_Arrow]

1) In your analog input task, you've added 20 channels. So, the order of the data in the array is simply the order in which you added the channels. Is what you have not working?

2) Since you are using numerics as display (not graphs), you don't need to use the Wfm datatype, and thus have all that coercing going on. I would setup the Sample Clock after your AI Task and wire it to Continuous Samples, "rate" of 1000, and set the polymorphic Read to 2D DBL NChan NSamp, and pick the data out of the resulting 2D array. Each row is a channel. Average the row to get a simple DBL value.

3) You don't have to wire a number to each of the Index Array inputs if you expect to get the data sequentially. When you drag the Index Array, LabVIEW assumes you want to get the data sequentially. (that was covered by Dennis as I was typing)

edit: yeah, You should not use the word "real time" and have a 1000mS loop! 🙂

Message Edited by Broken Arrow on 03-16-2009 07:32 AM

Message Edited by Broken Arrow on 03-16-2009 07:34 AM

[soundofwind]

Thank you so much. That's what i expected to get