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data acquisition at every 5 minutes and at longer intervals

How to program in LabVIEW 8.5 to acquire  data at longer intervals? say for an example at 2 minutes, at 5 minutes and at half an hour etc.
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Message 1 of 7
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You can use

-the "Wait until Next ms Multiple"

-A event structure with a timeout.

 -A timed Loop.

In all the above methods you can set the interval programmatically, if you need to.

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Message 2 of 7
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I did try it, but the limitations are/ or let me tell my requirements are

  • I want to update my indicators at three readings/ sec or little faster
  • at the same time, I want to have longer sampling time to write the data in to the file

How to achieve both the things? now I have done it using local Variables that is

Two parallel loops, one is while loop, where DAQmx is running and another is timed loop, where data writing is done. daqmx output is created as the local variable and it is fed to the measurement file. it is working well.

But I am looking for the better way. because in this method there is some delay in first readings. also I feel that this code is not so good. I could say that I did it some way.

Dbase and mss both are me



Message Edited by DBase on 02-16-2008 09:28 AM
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Message 3 of 7
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I don't quite understand how you done it, but:
you can use 2 timed loops in parallel. Each one , for each job.
You can set the priority settings too.
You can compine them to only one loop, if the period of the longer loop is a multiplier of the sorter one.
 
I don't see why this is "no good way".  I think it is the best way (well.. depending of your needs)
Post a simplified jpg of your program and maybe i can say something more.
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Have you try something like this? I know it's not neat, but at least it must work. You can make it a sub-vi, then put it inside your sampling cycle to create the delay per cycle.
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Message 5 of 7
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or have a case structure for the logging that executes at a multiple of the loop-iteration
 


Message Edited by Tohatsu on 02-19-2008 06:39 AM
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Message 6 of 7
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Sir,

I want to acquire data in every 5 minute. can u tell me method in labview so I can acquire data.  

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Message 7 of 7
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