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The Code for the Moisture sensor is based on its technical data (Bosch, 2024), where 0v = 0%rH [NOT VERIFIED]  which linearly scales to 10v 5v = 100%rH[NOT VERIFIED]. This means that linear interpolation is utilized to scale the input voltage too an output in %rH.

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

This means that the inputs needs to be,

• sensor_reading:REAL;
• set_point_in_pRhREAL;
• alarm_delay:TIME;
• max_rPhpRh:REAL;
• max_rPhpRh_in_volts:REAL;
• min_rPhpRh:REAL;
• min_rPhpRh_in_volts:REAL;

And the outputs needs to be,

• rPhpRh_read:REAL;
• alarm_high:BOOL;
• alarm_low:BOOL;

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The coded implementation looks like this,

Visually the new function block looks as following,

Image Added

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).

Bosch. (2024). BME688: Digital low power gas, pressure, temperature & humidity sensor with AI. [pdf] February 2024, Document revision 1.3. Available at: https://www.bosch-sensortec.com/media/boschsensortec/downloads/datasheets/bst-bme688-ds000.pdf (Accessed: 28 May 2024).