The Pressure sensor utilized is from Gens and has the following parts number: 3500B350MG05G000 

The code for the pressure sensor is based off its techincal data (Gems Sensors & Controls, n.d.), where the minum current of 4mA equals a pressure of 0bar and the maximum current of 20mA equals a pressure of 350mbar.


Linear interpolation is performed with the following function (Chapra and Canale, 2015),


This means that the inputs needs to be,

  • sensor_reading:REAL;
  • max_bar:REAL;
  • max_bar_in_mAmps:REAL;
  • min_bar:REAL;
  • min_bar_in_mAmps:REAL;


And the outputs needs to be,

  • bar_read:REAL;

This Function block could have been a Function. However, to make it easy to expand on the function block in the future, it was created as a Function Block.


The coded implementation looks like this,


Visually the new function block looks as following,


References:

Chapra, S.C. and Canale, R.P. (2015). Numerical Methods for Engineers. 7th ed. New York: McGraw-Hill Education. [pdf] Available at: https://gdcboysang.ac.in/About/Droid/uploads/Numerical%20Methods.pdf (Accessed: 28 May 2024).


Gems Sensors & Controls. (n.d.). 3500 Series: Compact Low Pressure OEM Pressure Transmitters. [pdf] Available at: https://media.distrelec.com/Web/Downloads/_t/ds/Gems_3500_eng_tds.pdf (Accessed: 28 May 2024).


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