forked from M-Labs/ionpak-thermostat
31 lines
719 B
Rust
31 lines
719 B
Rust
use libm::F32Ext;
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/// Steinhart-Hart equation parameters
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#[derive(Clone, Debug)]
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pub struct Parameters {
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pub a: f32,
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pub b: f32,
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pub c: f32,
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/// Parallel resistance
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///
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/// Not truly part of the equation but required to calculate
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/// resistance from voltage.
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pub parallel_r: f32,
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}
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impl Parameters {
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/// Perform the voltage to temperature conversion.
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///
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/// Result unit: Kelvin
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///
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/// TODO: verify
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pub fn get_temperature(&self, voltage: f32) -> f32 {
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let r = self.parallel_r * voltage;
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let ln_r = r.abs().ln();
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let inv_temp = self.a +
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self.b * ln_r +
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self.c * ln_r * ln_r * ln_r;
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1.0 / inv_temp
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}
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}
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