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Help calibrating some instruments

  1. Dec 12, 2006 #1
    It was difficult deciding where to put this -- so feel free to move this post if you'd like!!

    I am working on calibrating some Omega pressure transducers, and I just want some verification on my overall error. Model -- PX303 various pressures.

    Zero Balance -- with 0 PSI (gage pressure) on the instrument, my voltage output can vary by this percentage. This is an adjustment to make in my software -- i.e. if it is saying .6 Volts is zero, I am OK because the 0.1V difference is still within the instruments zero balance range.

    Span Tolerance -- if I put the upper limit of pressure on the instrument, this is the voltage variation allowed on the upper end i.e I might not get 5.5V output on the max PSI on the deadweight tester.

    I need verification if that's indeed what these ranges are, and if so -- Can I not include them in my error calculation? By making the software adjustments, the only error left should be the accuracy error??

    Last edited: Dec 12, 2006
  2. jcsd
  3. Dec 12, 2006 #2


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    Staff Emeritus
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    Gold Member

    Post the model number of your transducer. So the rest of us can look at the documention for your transducers. There is no standard terminology for these terms, we need to see the documention.
  4. Dec 13, 2006 #3
    I added the model number above -- it is a voltage output transducer.
  5. Dec 19, 2006 #4
    Trying to bump this up to the top -- hoping someone can offer some advice. Thanks!!!
  6. Dec 19, 2006 #5


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    Staff: Mentor

    Well, to save others from having to google it, here is the datasheet for the part:


    It says it comes with an operator's manual -- what does that say about calibration? Do you have any web pointers to the kind of calibration that you are trying to do? This is calibration in software to make the sensor overall more accurate, right?
  7. Dec 19, 2006 #6
    Operation manual -- yeah right. I talked to Omega, and they said most companies will send the transducers to them to confirm the calibrations. There are no internal adjustments that can be made....

    What I am looking to do is just confirm the transducers are still working within their specified parameters.

    I guess my question is meant to be generic -- What do these different accuracy ranges mean and am I accounting for them correctly when confirming the working condition of these instruments.
  8. Dec 19, 2006 #7


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    With transducers like that (strain gauge based) the calibration is really in the data collection. There is nothing to tweak in a transducer like what you could adjust in older dial gauges. You are usually given a calibration with the transducer.

    In your case your definitions are correct. The zero balance is balancing the bridge for the strain gauges in the transducer. The span tolerance takes into account all of those little niceties that go along with strain gauges like temperature and transverse sensitivities.
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