pls, help to make a data logger

Discussion in 'General Electronics Chat' started by Yuri B., Mar 3, 2010.

  1. Yuri B.

    Thread Starter New Member

    Aug 10, 2009
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    Hello.
    I need to make a 3 phase 400 V voltage level check over a period of time (at some 1 sec intervals) but do not want to buy a voltage logger for that purpose (besause am really tight budgeted).
    Does somebody know an economical way how to make a self-made logger from a laptop ?
     
  2. someonesdad

    Senior Member

    Jul 7, 2009
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    If you search some recent posts I made, I found a $25 data logger that might fit the bill. While it's no doubt not very sophisticated and missing features, it may do what you need to do...
     
  3. kubeek

    AAC Fanatic!

    Sep 20, 2005
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    Kinda depends on what exactly you want to measure on those 3 phases. 1/sec means you would have to do some averaging of the effective voltage, and than sample it with the logger.
     
  4. t06afre

    AAC Fanatic!

    May 11, 2009
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    I think it would Help if Yuri B. told us more about this project. Like what he want to achieve in this project. Also what kind of project this is(home,school, etc). And of course I do not mind helping in a school project.
     
  5. Yuri B.

    Thread Starter New Member

    Aug 10, 2009
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    A site with a water cooling chiller - 2 scroll compressors. When it was summer, and it run, it run fine at day but during night hours the both or one of the 50 A (C type) MCBs were periodically blowing. By that voltage was within norm, pressures too, amperage drawn did not exceed 20A
    Clearly something wrong with the power supply at exactly the nights. Unclear what: overvoltage, undervoltage, some distortions ?
    My boss does not want to pay for a logger but will soon ask me to name the exact cause of the malfunction described when the chiller will again be brought to action.

    Does there exist a free software with which to built a trend graph of voltage samples ?
    How to apply an analogue/digital converter to a PC ?
    Through USB or RS232 ?
    Maybe I am asking too much and am surely showing flagrant ignorance, but nonetheless. And thank you for your replies.

    )I even have such ridiculous thought as web camera taking images of multimeters measuring voltage.)
     
  6. rogs

    Active Member

    Aug 28, 2009
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    Don't see why that is ridiculous at all?!!

    You only need to do this once, so no point in spending a lot of time or cash.
    Intefacing a data logger with a high voltage 3 phase supply is going to need some careful safety issues correctly addressed -OK if you have the expertise, but time consuming for a single experiment.
    Using a time lapse webcam to photograph a multimeter ( and possibly a clock?) at preset intervals seems a very simple and effective way of solving your problem. And with excellent opto isolation - so good from a safety point of view! :)

    You'll probably need something like this: http://www.nimisis.com/projects/flix.php

    Not too expensive!
     
  7. t06afre

    AAC Fanatic!

    May 11, 2009
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    I also agree if you think the webcam setup will be the quickest and cheapest solution go for it. It will give your data and that is the most important thing. Not how you get your data
     
  8. kubeek

    AAC Fanatic!

    Sep 20, 2005
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    I would:
    a) ask the company which made the chiller how is such a malfunction possible
    and if they don´t know
    b) use three more multimeters and measure the current as well

    I suspect that either one phase goes off when the motors die, or there is some malfunction in the chiller which overloads the compressors like a closed valve on the input or output.
     
  9. Yuri B.

    Thread Starter New Member

    Aug 10, 2009
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    Thank you all for information you have provided.
    I had been only considering El-USB, but now have the cheaper choice of
    DI-194RS logger
    as well as Flix software for web cameras (and am glad my idea about the latter turned sensible)

    This type of chillers works well elsewhere (in the town) but that one is in a sort of countryside. In principal, heat load decreased at nights, so pressures, so currents, the only possibility of the constantly tripping MCBs at nights remains the level of voltage supplied during that time.
    The both motors are still alive - after many tens of tripping. The unit is also guarded by a relay against phase loss and inbalance.
     
    Last edited: Mar 5, 2010
  10. retched

    AAC Fanatic!

    Dec 5, 2009
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    Its odd there is not a phase monitor integrated into the chillers power system. They are commonplace within my realm.
     
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