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Adjusted error handling and organization of transducers.

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This commit is contained in:
Zachary Levy
2026-04-12 12:44:21 -07:00
parent 2a0d9e0097
commit f06582caed
6 changed files with 200 additions and 196 deletions
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src/transducer/part/lm35.rs
-16
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@@ -1,16 +0,0 @@
use crate::error::InvalidValue;
use crate::quantity::{DeciCelsius, MilliVolts, Quantity};
#[inline]
pub fn convert(
voltage: MilliVolts<i16>,
) -> Result<DeciCelsius<i16>, InvalidValue> {
const MIN_VOLTAGE: MilliVolts<i16> = MilliVolts(-550);
const MAX_VOLTAGE: MilliVolts<i16> = MilliVolts(1_500);
if voltage >= MIN_VOLTAGE && voltage <= MAX_VOLTAGE {
Ok(DeciCelsius(voltage.value()))
} else {
Err(InvalidValue)
}
}
src/transducer/part/mod.rs
+2 -8
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@@ -1,10 +1,4 @@
mod thermocouple;
#[cfg(feature = "lm35")]
pub mod lm35;
pub mod thermocouple;
#[cfg(feature = "thermistor")]
pub mod thermistor;
#[cfg(feature = "thermocouple-k")]
pub use thermocouple::type_k as thermocouple_k;
pub mod thermistor;
src/transducer/part/thermocouple.rs
+198
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@@ -0,0 +1,198 @@
#[cfg(feature = "thermocouple-k")]
pub mod k {
//! Type K thermocouple conversion using [f64] arithmetic internally.
//!
//! All conversion functions clamp their inputs to the valid range rather than returning errors.
//! Use the `MIN_*` / `MAX_*` constants to check whether an input is in range before
//! calling a conversion function if out-of-range detection is needed.
use libm::exp;
use crate::quantity::{Celsius, MilliVolts};
// ----- Voltage-to-temperature constants -----
/// Minimum voltage accepted by the NIST inverse polynomial (-5.891 mV ≈ -210 °C).
pub const MIN_VOLTAGE: MilliVolts<f64> = MilliVolts(-5.891);
/// Maximum voltage accepted by the NIST inverse polynomial (54.886 mV ≈ 1372 °C).
pub const MAX_VOLTAGE: MilliVolts<f64> = MilliVolts(54.886);
// ----- Temperature-to-voltage constants -----
/// Minimum temperature accepted by the NIST forward polynomial (-270 °C).
pub const MIN_TEMP_POLY: Celsius<f64> = Celsius(-270.0);
/// Maximum temperature accepted by the NIST forward polynomial (1372 °C).
pub const MAX_TEMP_POLY: Celsius<f64> = Celsius(1372.0);
/// Minimum temperature accepted by the Seebeck approximation (-2 °C).
pub const MIN_TEMP_SEEBECK: Celsius<f32> = Celsius(-2.0);
/// Maximum temperature accepted by the Seebeck approximation (800 °C).
pub const MAX_TEMP_SEEBECK: Celsius<f32> = Celsius(800.0);
// ----- Voltage to temperature (inverse polynomial) -----
/// Core NIST ITS-90 inverse polynomial for type K.
/// Input is clamped to [`MIN_VOLTAGE`]..=[`MAX_VOLTAGE`].
fn voltage_to_temp(voltage: MilliVolts<f64>) -> Celsius<f32> {
let mv = voltage.0.clamp(MIN_VOLTAGE.0, MAX_VOLTAGE.0);
let mv_pow2 = mv * mv;
let mv_pow3 = mv_pow2 * mv;
let mv_pow4 = mv_pow3 * mv;
let mv_pow5 = mv_pow4 * mv;
let mv_pow6 = mv_pow5 * mv;
let celsius = if mv >= -5.891 && mv <= 0.0 {
let mv_pow7 = mv_pow6 * mv;
let mv_pow8 = mv_pow7 * mv;
2.5173462E+1 * mv
+ -1.1662878 * mv_pow2
+ -1.0833638 * mv_pow3
+ -8.9773540E-1 * mv_pow4
+ -3.7342377E-1 * mv_pow5
+ -8.6632643E-2 * mv_pow6
+ -1.0450598E-2 * mv_pow7
+ -5.1920577E-4 * mv_pow8
} else if mv > 0.0 && mv < 20.644 {
let mv_pow7 = mv_pow6 * mv;
let mv_pow8 = mv_pow7 * mv;
let mv_pow9 = mv_pow8 * mv;
2.508355E+1 * mv
+ 7.860106E-2 * mv_pow2
+ -2.503131E-1 * mv_pow3
+ 8.315270E-2 * mv_pow4
+ -1.228034E-2 * mv_pow5
+ 9.804036E-4 * mv_pow6
+ -4.413030E-5 * mv_pow7
+ 1.057734E-6 * mv_pow8
+ -1.052755E-8 * mv_pow9
} else {
// mv >= 20.644 && mv <= 54.886
-1.318058e2
+ 4.830222E+1 * mv
+ -1.646031 * mv_pow2
+ 5.464731E-2 * mv_pow3
+ -9.650715E-4 * mv_pow4
+ 8.802193E-6 * mv_pow5
+ -3.110810E-8 * mv_pow6
};
Celsius(celsius as f32)
}
// ----- Public voltage-to-temperature conversions -----
/// Convert thermocouple voltage to temperature by directly adding the reference junction
/// temperature to the polynomial result for cold-junction compensation.
///
/// Can be useful compared to [`convert_seebeck`] when the reference temperature or the
/// temperature being read by the thermocouple is fairly close to 0 °C.
///
/// Voltage is clamped to [`MIN_VOLTAGE`]..=[`MAX_VOLTAGE`].
///
/// Uses the [NIST type K inverse polynomial](https://srdata.nist.gov/its90/type_k/kcoefficients_inverse.html).
#[inline]
pub fn convert_direct(
voltage: MilliVolts<f64>,
r_junction: Celsius<f32>,
) -> Celsius<f32> {
voltage_to_temp(voltage) + r_junction
}
/// Convert thermocouple voltage to temperature using a constant Seebeck coefficient to
/// correct the input voltage for cold-junction compensation.
///
/// Probably the right choice most of the time.
///
/// Voltage is clamped to [`MIN_VOLTAGE`]..=[`MAX_VOLTAGE`].
/// Reference junction temperature is clamped to [`MIN_TEMP_SEEBECK`]..=[`MAX_TEMP_SEEBECK`].
///
/// Uses the [NIST type K inverse polynomial](https://srdata.nist.gov/its90/type_k/kcoefficients_inverse.html).
#[inline]
pub fn convert_seebeck(
voltage: MilliVolts<f64>,
r_junction: Celsius<f32>,
) -> Celsius<f32> {
let voltage_correction = temp_to_voltage_seebeck(r_junction);
voltage_to_temp(MilliVolts(voltage.0 + voltage_correction.0 as f64))
}
/// Convert thermocouple voltage to temperature using the full NIST forward polynomial to
/// correct the input voltage for cold-junction compensation.
///
/// This is the most accurate method but uses the most processor cycles by a wide margin.
///
/// Voltage is clamped to [`MIN_VOLTAGE`]..=[`MAX_VOLTAGE`].
/// Reference junction temperature is clamped to [`MIN_TEMP_POLY`]..=[`MAX_TEMP_POLY`].
///
/// Uses the [NIST type K inverse polynomial](https://srdata.nist.gov/its90/type_k/kcoefficients_inverse.html).
#[inline]
pub fn convert_polynomial(
voltage: MilliVolts<f64>,
r_junction: Celsius<f64>,
) -> Celsius<f32> {
let voltage_correction = temp_to_voltage_poly(r_junction);
voltage_to_temp(MilliVolts(voltage.0 + voltage_correction.0 as f64))
}
// ----- Temperature to voltage (forward functions) -----
/// Convert a temperature to a type K thermocouple voltage using the full NIST forward
/// polynomial.
///
/// Temperature is clamped to [`MIN_TEMP_POLY`]..=[`MAX_TEMP_POLY`].
pub fn temp_to_voltage_poly(temperature: Celsius<f64>) -> MilliVolts<f32> {
let celsius = temperature.0.clamp(MIN_TEMP_POLY.0, MAX_TEMP_POLY.0);
let cel_pow2 = celsius * celsius;
let cel_pow3 = cel_pow2 * celsius;
let cel_pow4 = cel_pow3 * celsius;
let cel_pow5 = cel_pow4 * celsius;
let cel_pow6 = cel_pow5 * celsius;
let cel_pow7 = cel_pow6 * celsius;
let cel_pow8 = cel_pow7 * celsius;
let cel_pow9 = cel_pow8 * celsius;
let mv = if celsius >= -270.0 && celsius < 0.0 {
let cel_pow10 = cel_pow9 * celsius;
0.394501280250E-01 * celsius
+ 0.236223735980E-04 * cel_pow2
+ -0.328589067840E-06 * cel_pow3
+ -0.499048287770E-08 * cel_pow4
+ -0.675090591730E-10 * cel_pow5
+ -0.574103274280E-12 * cel_pow6
+ -0.310888728940E-14 * cel_pow7
+ -0.104516093650E-16 * cel_pow8
+ -0.198892668780E-19 * cel_pow9
+ -0.163226974860E-22 * cel_pow10
} else {
// celsius >= 0.0 && celsius <= 1372.0
let base = celsius - 0.126968600000E+03;
let exponent = -0.118343200000E-03 * (base * base);
let addition = 0.1185976 * exp(exponent);
-0.176004136860E-01
+ 0.389212049750E-01 * celsius
+ 0.185587700320E-04 * cel_pow2
+ -0.994575928740E-07 * cel_pow3
+ 0.318409457190E-09 * cel_pow4
+ -0.560728448890E-12 * cel_pow5
+ 0.560750590590E-15 * cel_pow6
+ -0.320207200030E-18 * cel_pow7
+ 0.971511471520E-22 * cel_pow8
+ -0.121047212750E-25 * cel_pow9
+ addition
};
MilliVolts(mv as f32)
}
/// Convert a temperature to a type K thermocouple voltage using a constant Seebeck
/// coefficient approximation (41 µV/°C).
///
/// Temperature is clamped to [`MIN_TEMP_SEEBECK`]..=[`MAX_TEMP_SEEBECK`].
#[inline]
pub fn temp_to_voltage_seebeck(temperature: Celsius<f32>) -> MilliVolts<f32> {
MilliVolts(0.041 * temperature.0.clamp(MIN_TEMP_SEEBECK.0, MAX_TEMP_SEEBECK.0))
}
}
src/transducer/part/thermocouple/mod.rs
-2
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@@ -1,2 +0,0 @@
#[cfg(feature = "thermocouple-k")]
pub mod type_k;
src/transducer/part/thermocouple/type_k.rs
-169
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@@ -1,169 +0,0 @@
//! Note - Thermocouple conversion uses [f64] arithmetic internally.
use libm::exp;
use crate::error::InvalidValue;
use crate::quantity::{Celsius, MilliVolts, Quantity};
fn _convert(
voltage: MilliVolts<f64>,
) -> Result<Celsius<f32>, InvalidValue> {
let mv = voltage.value();
let mv_pow2 = mv * mv;
let mv_pow3 = mv_pow2 * mv;
let mv_pow4 = mv_pow3 * mv;
let mv_pow5 = mv_pow4 * mv;
let mv_pow6 = mv_pow5 * mv;
if mv >= -5.891 && mv <= 0.0 {
let mv_pow7 = mv_pow6 * mv;
let mv_pow8 = mv_pow7 * mv;
let celsius = 2.5173462E+1 * mv
+ -1.1662878 * mv_pow2
+ -1.0833638 * mv_pow3
+ -8.9773540E-1 * mv_pow4
+ -3.7342377E-1 * mv_pow5
+ -8.6632643E-2 * mv_pow6
+ -1.0450598E-2 * mv_pow7
+ -5.1920577E-4 * mv_pow8;
Ok(Celsius(celsius as f32))
} else if mv > 0.0 && mv < 20.644 {
let mv_pow7 = mv_pow6 * mv;
let mv_pow8 = mv_pow7 * mv;
let mv_pow9 = mv_pow8 * mv;
let celsius = 2.508355E+1 * mv
+ 7.860106E-2 * mv_pow2
+ -2.503131E-1 * mv_pow3
+ 8.315270E-2 * mv_pow4
+ -1.228034E-2 * mv_pow5
+ 9.804036E-4 * mv_pow6
+ -4.413030E-5 * mv_pow7
+ 1.057734E-6 * mv_pow8
+ -1.052755E-8 * mv_pow9;
Ok(Celsius(celsius as f32))
} else if mv >= 20.644 && mv <= 54.886 {
let celsius = -1.318058e2
+ 4.830222E+1 * mv
+ -1.646031 * mv_pow2
+ 5.464731E-2 * mv_pow3
+ -9.650715E-4 * mv_pow4
+ 8.802193E-6 * mv_pow5
+ -3.110810E-8 * mv_pow6;
Ok(Celsius(celsius as f32))
} else {
Err(InvalidValue)
}
}
/// Convert from a voltage produced by a type k thermocouple to a temperature using polynomial and
/// directly adding the reference junction temperature to the result for offset compensation.
///
/// Can be useful compared to [convert_seebeck] when the reference temperature or the temperature
/// being read by the thermocouple is fairly close to 0.
///
/// This function uses the [NIST type K thermocouple linearisation polynomial](https://srdata.nist.gov/its90/type_k/kcoefficients_inverse.html).
#[inline]
pub fn convert_direct(
voltage: MilliVolts<f64>,
r_junction: Celsius<f32>,
) -> Result<Celsius<f32>, InvalidValue> {
let base_temp = _convert(voltage)?;
Ok(base_temp + r_junction)
}
/// Convert from a voltage produced by a type k thermocouple to a temperature using polynomial and
/// using a constant seebeck coefficient to correct the input voltage for offset compensation.
///
/// Probably the right choice most of the time.
///
/// This function uses the [NIST type K thermocouple linearisation polynomial](https://srdata.nist.gov/its90/type_k/kcoefficients_inverse.html).
#[inline]
pub fn convert_seebeck(
voltage: MilliVolts<f64>,
r_junction: Celsius<f32>,
) -> Result<Celsius<f32>, InvalidValue> {
let voltage_correction = temp_to_voltage_seebeck(r_junction)?;
_convert(MilliVolts(voltage.0 + voltage_correction.0 as f64))
}
/// Convert from a voltage produced by a type k thermocouple to a temperature using polynomial and
/// using a polynomial to correct the input voltage for offset compensation.
///
/// This is the most accurate method but uses the most processor cycles by a wide margin.
///
/// This function uses the [NIST type K thermocouple linearisation polynomial](https://srdata.nist.gov/its90/type_k/kcoefficients_inverse.html).
#[inline]
pub fn convert_polynomial(
voltage: MilliVolts<f64>,
r_junction: Celsius<f64>,
) -> Result<Celsius<f32>, InvalidValue> {
let voltage_correction = temp_to_voltage_poly(r_junction)?;
_convert(MilliVolts(voltage.0 + voltage_correction.0 as f64))
}
pub fn temp_to_voltage_poly(
temperature: Celsius<f64>,
) -> Result<MilliVolts<f32>, InvalidValue> {
let celsius = temperature.value();
let cel_pow2 = celsius * celsius;
let cel_pow3 = cel_pow2 * celsius;
let cel_pow4 = cel_pow3 * celsius;
let cel_pow5 = cel_pow4 * celsius;
let cel_pow6 = cel_pow5 * celsius;
let cel_pow7 = cel_pow6 * celsius;
let cel_pow8 = cel_pow7 * celsius;
let cel_pow9 = cel_pow8 * celsius;
if celsius >= -270.0 && celsius < 0.0 {
let cel_pow10 = cel_pow9 * celsius;
let mv = 0.394501280250E-01 * celsius
+ 0.236223735980E-04 * cel_pow2
+ -0.328589067840E-06 * cel_pow3
+ -0.499048287770E-08 * cel_pow4
+ -0.675090591730E-10 * cel_pow5
+ -0.574103274280E-12 * cel_pow6
+ -0.310888728940E-14 * cel_pow7
+ -0.104516093650E-16 * cel_pow8
+ -0.198892668780E-19 * cel_pow9
+ -0.163226974860E-22 * cel_pow10;
Ok(MilliVolts(mv as f32))
} else if celsius >= 0.0 && celsius <= 1372.0 {
let base = celsius - 0.126968600000E+03;
let exponent = -0.118343200000E-03 * (base * base);
let addition = 0.1185976 * exp(exponent);
let mv = -0.176004136860E-01
+ 0.389212049750E-01 * celsius
+ 0.185587700320E-04 * cel_pow2
+ -0.994575928740E-07 * cel_pow3
+ 0.318409457190E-09 * cel_pow4
+ -0.560728448890E-12 * cel_pow5
+ 0.560750590590E-15 * cel_pow6
+ -0.320207200030E-18 * cel_pow7
+ 0.971511471520E-22 * cel_pow8
+ -0.121047212750E-25 * cel_pow9
+ addition;
Ok(MilliVolts(mv as f32))
} else {
Err(InvalidValue)
}
}
#[inline]
pub fn temp_to_voltage_seebeck(
temperature: Celsius<f32>,
) -> Result<MilliVolts<f32>, InvalidValue> {
if temperature.value() >= -2.0 && temperature.value() <= 800.0 {
Ok(MilliVolts(0.041 * temperature.value()))
} else {
Err(InvalidValue)
}
}