M-Labs/thermostat
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Limit i_set within range of MAX1968 chip

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atse 2024-04-03 11:31:34 +08:00 committed by sb10q
parent 09be55e12a
commit 00d5feaa8d
2 changed files with 11 additions and 4 deletions
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9
src/channels.rs
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@ -25,6 +25,10 @@ use crate::{
pub const CHANNELS: usize = 2; pub const CHANNELS: usize = 2;
pub const R_SENSE: f64 = 0.05; pub const R_SENSE: f64 = 0.05;
// as stated in the MAX1968 datasheet
pub const MAX_TEC_I: f64 = 3.0;
// DAC chip outputs 0-5v, which is then passed through a resistor dividor to provide 0-3v range // DAC chip outputs 0-5v, which is then passed through a resistor dividor to provide 0-3v range
const DAC_OUT_V_MAX: f64 = 3.0; const DAC_OUT_V_MAX: f64 = 3.0;
@ -130,6 +134,11 @@ impl<'a> Channels<'a> {
} }
pub fn set_i(&mut self, channel: usize, i_set: ElectricCurrent) -> ElectricCurrent { pub fn set_i(&mut self, channel: usize, i_set: ElectricCurrent) -> ElectricCurrent {
// Silently clamp i_set
let i_ceiling = ElectricCurrent::new::<ampere>(MAX_TEC_I);
let i_floor = ElectricCurrent::new::<ampere>(-MAX_TEC_I);
let i_set = i_set.min(i_ceiling).max(i_floor);
let vref_meas = match channel.into() { let vref_meas = match channel.into() {
0 => self.channel0.vref_meas, 0 => self.channel0.vref_meas,
1 => self.channel1.vref_meas, 1 => self.channel1.vref_meas,

6
src/fan_ctrl.rs
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@ -11,13 +11,11 @@ use uom::si::{
use crate::{ use crate::{
hw_rev::HWSettings, hw_rev::HWSettings,
command_handler::JsonBuffer, command_handler::JsonBuffer,
channels::MAX_TEC_I,
}; };
pub type FanPin = PwmChannels<TIM8, pwm::C4>; pub type FanPin = PwmChannels<TIM8, pwm::C4>;
// as stated in the schematics
const MAX_TEC_I: f32 = 3.0;
const MAX_USER_FAN_PWM: f32 = 100.0; const MAX_USER_FAN_PWM: f32 = 100.0;
const MIN_USER_FAN_PWM: f32 = 1.0; const MIN_USER_FAN_PWM: f32 = 1.0;
@ -56,7 +54,7 @@ impl FanCtrl {
pub fn cycle(&mut self, abs_max_tec_i: ElectricCurrent) { pub fn cycle(&mut self, abs_max_tec_i: ElectricCurrent) {
self.abs_max_tec_i = abs_max_tec_i.get::<ampere>() as f32; self.abs_max_tec_i = abs_max_tec_i.get::<ampere>() as f32;
if self.fan_auto && self.hw_settings.fan_available { if self.fan_auto && self.hw_settings.fan_available {
let scaled_current = self.abs_max_tec_i / MAX_TEC_I; let scaled_current = self.abs_max_tec_i / MAX_TEC_I as f32;
// do not limit upper bound, as it will be limited in the set_pwm() // do not limit upper bound, as it will be limited in the set_pwm()
let pwm = (MAX_USER_FAN_PWM * (scaled_current * (scaled_current * self.k_a + self.k_b) + self.k_c)) as u32; let pwm = (MAX_USER_FAN_PWM * (scaled_current * (scaled_current * self.k_a + self.k_b) + self.k_c)) as u32;
self.set_pwm(pwm); self.set_pwm(pwm);