While loop and data acquisition timing worries

Hello everyone,
I apologize in advance if this is a silly question, but I could not find the answer around here.
I have made a VI to record continuously from 64 analog channels at a 5kHz sampling rate. I then stream this data to a tdms file. The data acquisition and write functions are in a while loop.
I the same loop, I have a bunch of other loops, that each run on their own wait timers to help limit the amount of memory they take up. I am now worried that this may somehow affect my data acquisition timing.
If I put a bunch of timed loops within another loop, does the outer loop run at the same pace as the slowest of the inner loops? And could that mess up my sampling rate?
I have attached my VI, in case what I just wrote makes no sense at all.
Thanks for any tips...
Attachments:
Record_M8viaDAQv3.vi ‏237 KB

Well, looking at your code you will only write to your TDMS file one time. You have multiple infinite loops within the main/outer loop. That means that the main loop will only run a single iteration because it cannot complete an iteration until all code within it completes. With at least two infinite loops inside the loop it will never complete. Not too mention the only way to stop your code is to hit the stop/abort button. NOt a very good way to stop your code. As someone once said using the abort to stop your code is like using a tree to stop your car. It will work but not advised.
As Ben mentioned try to understand data flow better. You have unnecessary sequence frames in your code where normal data flow will control the execution sequence.
Mark Yedinak
"Does anyone know where the love of God goes when the waves turn the minutes to hours?"
Wreck of the Edmund Fitzgerald - Gordon Lightfoot

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andyt writes:
> I am using a timed while loop and am unable to get the loop to run at
> a speed of less than 1ms (I am currently using the Wait(ms) function).
> How can I get a faster response?
>
> I am trying to create a virtual engine within a timed while loop and
> am unable to get the loop to run at a speed of less than 1ms (I am
> currently using the Wait(ms) function). This does not however allow
> realistic engine speeds. How can I overcome this? I have access to
> a PCI-MIO-16E-4 board.
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Attachments:
new_control_and_acquisition_program.vi ‏946 KB

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Please do NOT attach .bmp images with the extension changed to .jpg to circumvent the forum filters!
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thedunnyman wrote:
How do I do this? Creating table while looping through dates?
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daq_printscreen.GIF ‏45 KB

siva0182 wrote:
Find attached the picture of the vi where I tried to put in timers.one in each of the frame and at the end added one more frame just to measure the time elapsed .
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But surprisingly I tried displaying the actual timer value at the start and at the start of sourcemeter read function ..but the display of both indicators is almost equal with little difference of only 10 msec.????? I'm not sure which of the several timers you are referring to here. What is the value going into the wait function between the VISA write and the Keithly VI?
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PID while.vi ‏100 KB

My problem is the following. Both of the NI-DAQ I placed using DAQ Assist, require to be in a while loop.
-If
I place them in separate loops, I have the problem of passing
information between the Input NI-DAQ and the PID, and also between the
PID and the Output NI-DAQ.
This is the best option---Use QUEUE or Functional global or something else to tranfer the data to and fro
How do I make that QUEUE or Functional global?
-If I place them both in one big loop, an error occurs saying that the selected buffer size is too small (Error -200609).
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Attachments:
SyncTimedLoop32.vi ‏228 KB

hwm wrote:
2. When it is running, I click on stop button, why it won't stop?
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hwm wrote:
1. In Loop 3, when the comparison (x>20.85) is true, Loop1, Loop2 and Loop3 are stopped, why it won't quit the while loop (I have wired it to while loop stop)?
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shiftreg.JPG ‏56 KB

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ShiftRegLoop.JPG ‏54 KB

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Read Measurement.PNG ‏44 KB
Read Measurement.PNG ‏44 KB

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Saint
"Kevin Powell" ha scritto nel messaggio
news:[email protected]..
>
> I am a Labview user who would like to capture video and data (from one
video
> camera and 4 strain gauges) simultaneously, then be able to play the video
> whilst being able to process the data streams. Is there a simple way to do
> this? - Thanks!

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Spectrometer Control V3.0.vi ‏113 KB

lightblue,
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On Tue, 3 Feb 2004 09:03:07 -0600 (CST), jujian wrote:
>Although many topics of simultaneous analog output and input can be
>found in NI Developer Zone, I have not found a case similar to my
>project. I'm trying to generate a 1kHz sine wave by using the analog
>output of NI DAQPad-6070E, and acquire one channel input signal
>simultaneously. I found most of the examples can not work properly
>above 100Hz. Any suggestions are welcome. Thank you.
>
>Jian

While loop and data acquisition timing worries

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