calibration of weight device

Discussion in 'General Electronics Chat' started by ghanim, Feb 1, 2010.

  1. ghanim

    Thread Starter New Member

    May 21, 2009
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    Here is the details of the issue. We regularly calibrate the weighing devices to insure the consistancy of the work. The calibration process goes as follows:

    We have 50 pieces with standard weight, 20Kgs each which makes a total of 1000kgs, the half of the maximum capacity. We put them in steps and with each step we observe what the indicator reads to make sure that it works properly.

    The details of the last calibration process are:

    When we put 5 pieces (Standard 100kgs) the indicator reads (99kgs), when we put 10 pieces (Standard 200kgs) the indicator shows (199kgs), when we put 15 pieces (Standard 300kgs) the indicator reads (298kgs) then we put 50 pieces (Standard 1000kgs) the indicator reads (995kgs)

    Keep in mind that the tolerance is always kept to zero

    So the weighing indicator which we are talking about here is PRECIA MOLEN indicator with the serial number 02F724098

    Now I think you have a clear idea about the problem so please send me the ( process installation document) because I just have the user manual here which isn't complete.
     
  2. KMoffett

    AAC Fanatic!

    Dec 19, 2007
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  3. beenthere

    Retired Moderator

    Apr 20, 2004
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    You're actually checking the calibration by placing weights on the platform.

    Adjusting the scale might be possible with a trimmer potentiometer that affects the response of the internal circuitry. There may be another trimmer that sets the zero (unweighted) condition. It's also possible that calibration is done by an internal ROM that is used as a lookup table by a microprocessor.

    The manufacturer may tell you to return the scale for recalibrating.
     
  4. t06afre

    AAC Fanatic!

    May 11, 2009
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    This was a strange statement. Can you elaborate. All measurement systems will have some error. And how accurate is your test weights? Are they also tested.
     
  5. Duane P Wetick

    Active Member

    Apr 23, 2009
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    One thing I found out when weighing things in a laboratory is that, if you need accuracy to 3 places, you must measure to 4 places, because of the uncertainty in the LSD (least significant digit).

    Cheers, DPW [ Everything has limitations...and I hate limitations.]
     
  6. beenthere

    Retired Moderator

    Apr 20, 2004
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    If this scale is used for weighing some substance for sale, then some nice people from a federal outfit come by periodically to check it. It must present an accurate response to their check weights or it gets officially removed from service.

    We need the OP to check in on this.
     
  7. ghanim

    Thread Starter New Member

    May 21, 2009
    5
    0
    Thanks guys I have contact the manufacture and the problem is solved
     
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