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PGA305EVM-034: TC & NL coefficients and Scaling Factors

Igor Giterman
Prodigy 145 points

Part Number: PGA305EVM-034

I need to automate pressure sensor calibration for production quantities.

So, I need to develop a custom software for my equipment.

PGA305EVM-034 Users manual shows one example for 1 temperature and 3 Pressure points (page 84).

Can you define/explain how the TC & NL coefficients and Scaling Factors are calculated for 4T4P setup?

Thank you for your help.

Regards,

Igor

  • 0
    TI__Guru** 113765 points

    Hi Igor,

    A 4P-4T linear regression uses four pressure/temperature values at four temperatures .  In the GUI, instead of selecting 3P-1T you can select 4P-4T from the drop-down.  The boxes to fill in will now show two tables for pressure and temperature for four measurements at four temperatures.  You can think of this as a 4x4 matrix.  The end result of the linear regression is 16 coefficients.  As there are only EEPROM values for 16 coefficients, the maximum is a 4P-4T.  As far as the linear regression process, I will not begin to explain the math and will require additional research.  There are several methods for linear regression with varying outcomes.  Some outcomes will have a better linear fit than others.

    There is a DLL available for making the computations based on a Matlab script.  There is a discussion regarding the DLL that I believe I sent in a former thread.

    https://e2e.ti.com/support/sensors-group/sensors/f/sensors-forum/852425/pga305-data-representation-coefficients-calculation

    Best regards,

    Bob B