Zachary Levy
39 lines
1.3 KiB
Rust
39 lines
1.3 KiB
Rust
use crate::quantity::{Kelvins, Ohms};
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use libm::{log, logf};
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/// Convert thermistor resistance to a temperature using beta parameter equation
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pub fn convert_beta(
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resistance: Ohms<f32>,
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beta: f32,
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reference_temp: Kelvins<f32>,
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reference_resist: Ohms<f32>,
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) -> Kelvins<f32> {
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let kelvins = 1.0 / ((logf(resistance.0 / reference_resist.0) / beta) + 1.0 / reference_temp.0);
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Kelvins(kelvins)
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}
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/// Convert thermistor resistance to a temperature using Steinhart-Hart equation
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pub fn convert_steinhart(resistance: Ohms<f64>, a: f64, b: f64, c: f64) -> Kelvins<f32> {
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let log_omhs = log(resistance.0);
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let kelvins = 1.0 / (a + b * log_omhs + c * log_omhs * log_omhs * log_omhs);
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Kelvins(kelvins as f32)
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}
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// ---------------------------------------------------------------------------------------------------------------------
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// ----- Tests ------------------------
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// ---------------------------------------------------------------------------------------------------------------------
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#[cfg(test)]
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mod tests {
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use float_cmp::assert_approx_eq;
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use crate::quantity::{OhmsVal, KelvinsVal};
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use super::*;
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#[test]
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fn convert_beta_test() {
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let temperature = convert_beta(1538.462.ohms(), 3950.0, 298.15.kelvins(), 100_000.0.ohms());
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assert_approx_eq!(f32, 435.31073, temperature.0);
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}
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}
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