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Pressure Transducer Gain and Scaling for DAQ system Software

Discussion in 'ISO 17025 - Calibration and Test Laboratories' started by west0prest0, May 23, 2024.

  1. west0prest0

    west0prest0 New Member

    May 22, 2024
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    I am a lab technician in a refrigeration lab, and this is my first year managing the calibration of our equipment. We occasionally use pressure transducers (one high side and one low side) in our development testing. Pressures are recorded in a Keysight workbench, where gain (+) and offset (-) scaling are applied to the channels.

    For example, a 0-1000 PSI 0-5Vdc transducer calibrated last year had gain and offset values of +199.89 and -1.92 for inputting into the DAQ.

    We switched to a new calibration firm this year. Amidst the anticipated growing pains, I believe a key part of the calibration process was overlooked. Historically, we received gain and offset values from the previous firm post-calibration for channel scaling in our DAQ software. I asked if we would receive these Mx+B offsets from the new firm during their on-site visit and was assured we would and that they would be on the cal cert. Unfortunately, the values are not the ones we need. They are merely slope and intercept of the pressures applied and measured.

    I am assuming the old gain and offsets were derived from post-calibration tuning to bring the values displayed on the Keysight closer to "true".

    The question I have is: Can I derive new gain and offset values for our DAQ software using the values available on the new calibration certificate?

    The new cert includes a slope and intercept and a data series of applied and measured pressures recorded during the calibration process. However, I don't have the VDC values at those applied pressures or a 0 point calibration data. I would like to avoid having to recalibrate them if possible.

    I'm not sure if this is the right place to ask this, but any insights and hints would be greatly appreciated. I would really like to figure this out.
    Excuse the long-winded first post and thank you for your time and help!
  2. Miner

    Miner Moderator Staff Member

    Jul 30, 2015
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    Greater Milwaukee USA
    The intercept is equivalent to the offset, and the slope is equivalent to the gain.

    BradM likes this.
  3. BradM

    BradM Moderator Staff Member

    Jul 31, 2015
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    Arlington, TX
    Welcome to the forum!! My apologies; a few questions. So you have these 0-5vdc transducers that are calibrated. How are they calibrated? Are they calibrated separately than the workbench input?

    If they are calibrated separately, how is the workbench calibrated/verified?