M-Labs/thermostat
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clamp TEC settings to a valid & design specs range

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- Not respecting the design specs can cause hardware to get stuck in unrecoverable state
This commit is contained in:
linuswck 2024-05-10 12:25:27 +08:00
parent 925601f4f5
commit 1007982b48
3 changed files with 32 additions and 23 deletions
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51
src/channels.rs
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@ -1,5 +1,6 @@
use core::cmp::max_by;
use core::{cmp::max_by, marker::PhantomData};
use heapless::{consts::U2, Vec};
use num_traits::Zero;
use serde::{Serialize, Serializer};
use smoltcp::time::Instant;
use stm32f4xx_hal::hal;
@ -32,12 +33,24 @@ pub enum PinsAdcReadTarget {
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;
// From design specs
pub const MAX_TEC_I: ElectricCurrent = ElectricCurrent {
dimension: PhantomData,
units: PhantomData,
value: 2.0,
};
pub const MAX_TEC_V: ElectricPotential = ElectricPotential {
dimension: PhantomData,
units: PhantomData,
value: 4.0,
};
// 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;
const DAC_OUT_V_MAX: ElectricPotential = ElectricPotential {
dimension: PhantomData,
units: PhantomData,
value: 3.0,
};
// TODO: -pub
pub struct Channels {
channel0: Channel<Channel0>,
@ -128,7 +141,7 @@ impl Channels {
/// i_set DAC
fn set_dac(&mut self, channel: usize, voltage: ElectricPotential) -> ElectricPotential {
let value = ((voltage / ElectricPotential::new::<volt>(DAC_OUT_V_MAX)).get::<ratio>() * (ad5680::MAX_VALUE as f64)) as u32 ;
let value = ((voltage / DAC_OUT_V_MAX).get::<ratio>() * (ad5680::MAX_VALUE as f64)) as u32 ;
match channel {
0 => self.channel0.dac.set(value).unwrap(),
1 => self.channel1.dac.set(value).unwrap(),
@ -139,11 +152,7 @@ impl Channels {
}
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 i_set = i_set.min(MAX_TEC_I).max(-MAX_TEC_I);
let vref_meas = match channel.into() {
0 => self.channel0.vref_meas,
1 => self.channel1.vref_meas,
@ -318,7 +327,7 @@ impl Channels {
best_error = error;
start_value = prev_value;
let vref = (value as f64 / ad5680::MAX_VALUE as f64) * ElectricPotential::new::<volt>(DAC_OUT_V_MAX);
let vref = (value as f64 / ad5680::MAX_VALUE as f64) * DAC_OUT_V_MAX;
match channel {
0 => self.channel0.vref_meas = vref,
1 => self.channel1.vref_meas = vref,
@ -378,22 +387,22 @@ impl Channels {
}
}
pub fn get_max_v(&mut self, channel: usize) -> ElectricPotential {
pub fn get_max_v(&mut self, channel: usize) -> (ElectricPotential, ElectricPotential) {
let max = 4.0 * ElectricPotential::new::<volt>(3.3);
let duty = self.get_pwm(channel, PwmPin::MaxV);
duty * max
(duty * max, MAX_TEC_V)
}
pub fn get_max_i_pos(&mut self, channel: usize) -> (ElectricCurrent, ElectricCurrent) {
let max = ElectricCurrent::new::<ampere>(3.0);
let duty = self.get_pwm(channel, PwmPin::MaxIPos);
(duty * max, max)
(duty * max, MAX_TEC_I)
}
pub fn get_max_i_neg(&mut self, channel: usize) -> (ElectricCurrent, ElectricCurrent) {
let max = ElectricCurrent::new::<ampere>(3.0);
let duty = self.get_pwm(channel, PwmPin::MaxINeg);
(duty * max, max)
(duty * max, MAX_TEC_I)
}
// Get current passing through TEC
@ -435,21 +444,21 @@ impl Channels {
pub fn set_max_v(&mut self, channel: usize, max_v: ElectricPotential) -> (ElectricPotential, ElectricPotential) {
let max = 4.0 * ElectricPotential::new::<volt>(3.3);
let duty = (max_v / max).get::<ratio>();
let duty = (max_v.min(MAX_TEC_V).max(ElectricPotential::zero()) / max).get::<ratio>();
let duty = self.set_pwm(channel, PwmPin::MaxV, duty);
(duty * max, max)
}
pub fn set_max_i_pos(&mut self, channel: usize, max_i_pos: ElectricCurrent) -> (ElectricCurrent, ElectricCurrent) {
let max = ElectricCurrent::new::<ampere>(3.0);
let duty = (max_i_pos / max).get::<ratio>();
let duty = (max_i_pos.min(MAX_TEC_I).max(ElectricCurrent::zero()) / max).get::<ratio>();
let duty = self.set_pwm(channel, PwmPin::MaxIPos, duty);
(duty * max, max)
}
pub fn set_max_i_neg(&mut self, channel: usize, max_i_neg: ElectricCurrent) -> (ElectricCurrent, ElectricCurrent) {
let max = ElectricCurrent::new::<ampere>(3.0);
let duty = (max_i_neg / max).get::<ratio>();
let duty = (max_i_neg.min(MAX_TEC_I).max(ElectricCurrent::zero()) / max).get::<ratio>();
let duty = self.set_pwm(channel, PwmPin::MaxINeg, duty);
(duty * max, max)
}
@ -509,8 +518,8 @@ impl Channels {
PwmSummary {
channel,
center: CenterPointJson(self.channel_state(channel).center.clone()),
i_set: (self.get_i(channel), ElectricCurrent::new::<ampere>(3.0)).into(),
max_v: (self.get_max_v(channel), ElectricPotential::new::<volt>(5.0)).into(),
i_set: (self.get_i(channel), MAX_TEC_I).into(),
max_v: self.get_max_v(channel).into(),
max_i_pos: self.get_max_i_pos(channel).into(),
max_i_neg: self.get_max_i_neg(channel).into(),
}

2
src/config.rs
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@ -71,7 +71,7 @@ struct PwmLimits {
impl PwmLimits {
pub fn new(channels: &mut Channels, channel: usize) -> Self {
let max_v = channels.get_max_v(channel);
let (max_v, _) = channels.get_max_v(channel);
let (max_i_pos, _) = channels.get_max_i_pos(channel);
let (max_i_neg, _) = channels.get_max_i_neg(channel);
PwmLimits {

2
src/fan_ctrl.rs
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@ -54,7 +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 as f32;
let scaled_current = self.abs_max_tec_i / MAX_TEC_I.get::<ampere>() 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);