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Limit i_set within range of MAX1968 chip #102

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sb10q merged 1 commits from atse/thermostat:limit-i_set into master 2024-04-24 18:05:20 +08:00
Conversation 0 Commits 1 Files Changed 2 +11 -4
2 changed files with 11 additions and 4 deletions
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9
src/channels.rs
View File

@ -25,6 +25,10 @@ use crate::{
pub const CHANNELS: usize = 2;
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
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 {
// 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() {
0 => self.channel0.vref_meas,
1 => self.channel1.vref_meas,

6
src/fan_ctrl.rs
View File

@ -11,13 +11,11 @@ use uom::si::{
use crate::{
hw_rev::HWSettings,
command_handler::JsonBuffer,
channels::MAX_TEC_I,
};
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 MIN_USER_FAN_PWM: f32 = 1.0;
@ -56,7 +54,7 @@ impl FanCtrl {
pub fn cycle(&mut self, abs_max_tec_i: ElectricCurrent) {
self.abs_max_tec_i = abs_max_tec_i.get::<ampere>() as f32;
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()
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);