src/channel_state.rs

@@ -16,13 +16,11 @@ use crate::{
 };
 
 const R_INNER: f64 = 2.0 * 5100.0;
-const VREF_SENS: f64 = 3.3 / 2.0;
 
 pub struct ChannelState {
     pub adc_data: Option<u32>,
     pub adc_calibration: ad7172::ChannelCalibration,
     pub adc_time: Instant,
-    /// VREF for the TEC (1.5V)
     pub vref: ElectricPotential,
     pub dac_value: ElectricPotential,
     pub pid_engaged: bool,
@@ -64,9 +62,8 @@ impl ChannelState {
     /// Get `SENS[01]` input resistance
     pub fn get_sens(&self) -> Option<ElectricalResistance> {
         let r_inner = ElectricalResistance::new::<ohm>(R_INNER);
-        let vref = ElectricPotential::new::<volt>(VREF_SENS);
         let adc_input = self.get_adc()?;
-        let r = r_inner * adc_input / (vref - adc_input);
+        let r = r_inner * adc_input / (self.vref - adc_input);
         Some(r)
     }
 

src/channels.rs

@@ -51,7 +51,8 @@ impl Channels {
         let pwm = pins.pwm;
         let mut channels = Channels { channel0, channel1, adc, pins_adc, pwm };
         for channel in 0..CHANNELS {
-            channels.channel_state(channel).vref = channels.read_vref(channel);
+            // FIXME: this reads 1.5 V instead of the expected 1.65 V.
+            // channels.channel_state(channel).vref = channels.read_vref(channel);
             channels.calibrate_dac_value(channel);
         }
         channels

src/main.rs

@@ -170,17 +170,17 @@ fn main() -> ! {
                                 Command::Show(ShowCommand::Input) => {
                                     for channel in 0..CHANNELS {
                                         if let Some(adc_input) = channels.channel_state(channel).get_adc() {
-                                            let vref = channels.channel_state(channel).vref;
+                                            let vref = channels.read_vref(channel);
                                             let dac_feedback = channels.read_dac_feedback(channel);
 
                                             let itec = channels.read_itec(channel);
-                                            let tec_i = (itec - vref) / ElectricalResistance::new::<ohm>(0.4);
+                                            let tec_i = -(itec - ElectricPotential::new::<volt>(1.5)) / ElectricalResistance::new::<ohm>(0.4);
 
                                             let tec_u_meas = channels.read_tec_u_meas(channel);
 
                                             let state = channels.channel_state(channel);
                                             let _ = writeln!(
-                                                socket, "channel {}: t={:.0} adc{}={:.3} adc_r={:.3} vref={:.3} dac_feedback={:.3} itec={:.3} tec={:.3} tec_u_meas={:.3} r={:.3}",
+                                                socket, "channel {}: t={} adc{}={} adc_r={} vref={} dac_feedback={} itec={} tec={} tec_u_meas={} r={:03}",
                                                 channel, state.adc_time,
                                                 channel, adc_input.into_format_args(volt, Abbreviation),
                                                 state.get_sens().unwrap().into_format_args(ohm, Abbreviation),
@@ -269,10 +269,9 @@ fn main() -> ! {
                                         match (state.get_adc(), state.get_sens(), state.get_temperature()) {
                                             (Some(adc), Some(sens), Some(temp)) => {
                                                 let _ = writeln!(
-                                                    socket, "- adc={:.6} r={:.0} temp{}={:.3}K",
+                                                    socket, "- adc={} r={} temp={:.3}K",
                                                     adc.into_format_args(volt, Abbreviation),
                                                     sens.into_format_args(ohm, Abbreviation),
-                                                    channel,
                                                     temp.into_format_args(degree_celsius, Abbreviation),
                                                 );
                                             }