Read from channels

[Dennis_Knutson]

If the graph is inside the loop, then the 25 sample will update 10 times faster.

[kdm7]

Okay

Thanks

[kdm7]

Hi Dennis_Knutson,

How can the 25 sample update 10 times faster when in both cases loop time is 0.25 seconds?

Graphs are displayed once in a loop.

[Dennis_Knutson]

Both loop times are NOT .25 seconds. To take 25 samples, it takes .025 seconds.

[kdm7]

No. 

I think I dint explain my question properly. 

I meant 25 samples are read 10 times and each data out is transposed, then appended, then transposed again to get a 6x250 array ( that is, 0.25 seconds).

[Dennis_Knutson]

You don't understand the answer. If your graph is inside inside the innermost loop, it will be updated at the rate I said. The total time for 10 loops is of course .25 seconds.

[kdm7]

There is only one loop. Both "25 sample reads" and the graphs are inside the same while loop, but on different sequential frames. The output of the "25 sample reads frame" is a 6x250 array data (i.e. 6 channels of 250 samples each which makes it a 0.25 seconds loop time.

[Dennis_Knutson]

What is the problem?

Post an image of your block diagram, please.

[kdm7]

I'll tell you what is actually done.

Six channels are configured.

In a frame (inside a while loop), 10 daqmx read functions reads 25 samples each (So there are ten 6x25 components). The output from each of the 10 daqmx read fns. are transposed and appended (using build array). This single output  is again transposed (which is now a 6x250 single component ). (So finally loop time is 0.25 secs.) This output is graphed (in the next frame and inside the same while loop.

My question is when we directly take 250 samples (loop time 0.25 secs) to get a 6x250 component, there is no difference in loop time, so is it that there is a difference in how the data is stacked? In the later case data is stacked column wise..

[crossrulz]

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@kdm7 wrote:

I'll tell you what is actually done.

Six channels are configured.

In a frame (inside a while loop), 10 daqmx read functions reads 25 samples each (So there are ten 6x25 components). The output from each of the 10 daqmx read fns. are transposed and appended (using build array). This single output  is again transposed (which is now a 6x250 single component ). (So finally loop time is 0.25 secs.) This output is graphed (in the next frame and inside the same while loop.

My question is when we directly take 250 samples (loop time 0.25 secs) to get a 6x250 component, there is no difference in loop time, so is it that there is a difference in how the data is stacked? In the later case data is stacked column wise..

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If you just make your task read 250 samples from 6 channels in one shot (instead of using the loops), then you end up with a 2D array with each channel's data being a row.