Saturday, June 2, 2012

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How to calibrate steam flow DP transmitter

  • Saturday, June 2, 2012
  • denizen robo
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  • How to calibrate steam flow DP transmitter

    flow_differential_pressure_steam_service_type

    Material
    Data sheet
    Pressure calibrator (std)
    Multimeter (std)
    Hart communicator
    Step
    *Ask panel man to put the controller in manual mode for control loop and to put it on MOS for ESD loop.
    *Hook up HART Communicator and verify some parameters by refer to data sheet. Typical parameters are, tag number, PV, LRV and URV.
    *Isolate the instrument from the process.
    *Release both pressure and drain low and high side liquid throughout manifold drain.
    *Connect pressure calibrator to high side of manifold
    *Expose the low side to atmosphere
    *Hook up a multimeter in series with the signal to the DCS to measure current signal.
    *Apply pressure as per data sheet LRV (normally 0mmH2O)
    Multimeter should show 4mA
    If not, do zero adjustment at transmitter using HART Communicator
    *Apply pressure as per data sheet URV
    Multimeter should show 20mA
    If not, do span adjustment at transmitter using HART Communicator
    *Verify the linearity by increasing and decreasing the pressure (0%,25%,50%,75%,100%,75%,50%,25% and 0%of range)
    *Fill up back water until half of seal pot.
    *After completion of the job ask panel operator to put loops back in normal mode or normalize the MOS

    Example calculation
    Instrument calibrated range: 0 – 2500 mmH2O
    Process calibrated range: 0 – 7000 kg/h
    Q =K  P
    0%  0 mmH2O = ( 0/2500) x 7000
    = 0 kg/h 
    50%  1250 mmH2O = ( 1250/2500) x 7000
    = 4949.75 kg/h 
    100%  2500 mmH2O = ( 2500/2500) x 7000
    = 7000 kg/h

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    1 Responses to “How to calibrate steam flow DP transmitter”

    calibration said...
    April 16, 2013 at 9:55 PM

    just linked this article on my facebook account. it’s a very interesting article for all...




    Instrument Calibrationi


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