channels: Start to make reports make sense

Names in the report make no sense, and expose implementation details.
Start simplifying the interface.

README.md

@@ -258,18 +258,15 @@ with the following keys.
 | Key            | Unit            | Description                                    |
 | ---            | :---:           | ---                                            |
 | `channel`      | Integer         | Channel `0`, or `1`                            |
-| `time`         | Seconds         | Temperature measurement time                         |
+| `time`         | Seconds         | Report timestamp (since thermostat reset)      |
-| `adc`          | Volts           | AD7172 input                                         |
+| `interval`     | Seconds         | ADC Sampling Interval                          |
-| `sens`         | Ohms            | Thermistor resistance derived from `adc`             |
+| `sens`         | Ohms            | Thermistor resistance                          |
-| `temperature`  | Degrees Celsius | Steinhart-Hart conversion result derived from `sens` |
+| `temperature`  | Degrees Celsius | Temperature derived from thermistor resistance |
 | `pid_engaged`  | Boolean         | `true` if in closed-loop mode                  |
-| `i_set`        | Amperes         | TEC output current                                   |
-| `dac_value`    | Volts           | AD5680 output derived from `i_set`                   |
-| `dac_feedback` | Volts           | ADC measurement of the AD5680 output                 |
-| `i_tec`        | Volts           | MAX1968 TEC current monitor                          |
-| `tec_i`        | Amperes         | TEC output current feedback derived from `i_tec`     |
-| `tec_u_meas`   | Volts           | Measurement of the voltage across the TEC            |
 | `pid_output`   | Amperes         | PID control output                             |
+| `i_set`        | Amperes         | Set TEC output current                         |
+| `i_measured`   | Amperes         | Measured current passing through TEC           |
+| `v_measured`   | Volts           | Measured voltage across TEC                    |
 
 Note: With Thermostat v2 and below, the voltage and current readouts `i_tec` and `tec_i` are noisy without the hardware fix shown in [this PR][https://git.m-labs.hk/M-Labs/thermostat/pulls/105].
 

src/channels.rs

@@ -408,15 +408,15 @@ impl Channels {
         (duty * max, MAX_TEC_I)
     }
 
-    // Get current passing through TEC
+    // Measure current passing through TEC
-    pub fn get_tec_i(&mut self, channel: usize) -> ElectricCurrent {
+    pub fn get_i_measured(&mut self, channel: usize) -> ElectricCurrent {
         (self.adc_read(channel, PinsAdcReadTarget::ITec, 16)
             - self.adc_read(channel, PinsAdcReadTarget::VREF, 16))
             / ElectricalResistance::new::<ohm>(0.4)
     }
 
-    // Get voltage across TEC
+    // Measure voltage across TEC
-    pub fn get_tec_v(&mut self, channel: usize) -> ElectricPotential {
+    pub fn get_v_measured(&mut self, channel: usize) -> ElectricPotential {
         (self.adc_read(channel, PinsAdcReadTarget::VTec, 16) - ElectricPotential::new::<volt>(1.5))
             * 4.0
     }
@@ -475,28 +475,23 @@ impl Channels {
 
     fn report(&mut self, channel: usize) -> Report {
         let i_set = self.get_i_set(channel);
-        let i_tec = self.adc_read(channel, PinsAdcReadTarget::ITec, 16);
+        let i_measured = self.get_i_measured(channel);
-        let tec_i = self.get_tec_i(channel);
+        let v_measured = self.get_v_measured(channel);
-        let dac_value = self.get_dac(channel);
         let state = self.channel_state(channel);
         let pid_output = ElectricCurrent::new::<ampere>(state.pid.y1);
         Report {
             channel,
             time: state.get_adc_time(),
             interval: state.get_adc_interval(),
-            adc: state.get_adc(),
             sens: state.get_sens(),
             temperature: state
                 .get_temperature()
                 .map(|temperature| temperature.get::<degree_celsius>()),
             pid_engaged: state.pid_engaged,
-            i_set,
-            dac_value,
-            dac_feedback: self.adc_read(channel, PinsAdcReadTarget::DacVfb, 1),
-            i_tec,
-            tec_i,
-            tec_u_meas: self.get_tec_v(channel),
             pid_output,
+            i_set,
+            i_measured,
+            v_measured,
         }
     }
 
@@ -576,8 +571,8 @@ impl Channels {
         serde_json_core::to_vec(&summaries)
     }
 
-        max_by(self.get_tec_i(0).abs(), self.get_tec_i(1).abs(), |a, b| {
     pub fn max_abs_i_measured(&mut self) -> ElectricCurrent {
+        max_by(self.get_i_measured(0).abs(), self.get_i_measured(1).abs(), |a, b| {
             a.partial_cmp(b).unwrap_or(core::cmp::Ordering::Equal)
         })
     }
@@ -588,17 +583,13 @@ pub struct Report {
     channel: usize,
     time: Time,
     interval: Time,
-    adc: Option<ElectricPotential>,
     sens: Option<ElectricalResistance>,
     temperature: Option<f64>,
     pid_engaged: bool,
-    i_set: ElectricCurrent,
-    dac_value: ElectricPotential,
-    dac_feedback: ElectricPotential,
-    i_tec: ElectricPotential,
-    tec_i: ElectricCurrent,
-    tec_u_meas: ElectricPotential,
     pid_output: ElectricCurrent,
+    i_set: ElectricCurrent,
+    i_measured: ElectricCurrent,
+    v_measured: ElectricPotential,
 }
 
 pub struct CenterPointJson(CenterPoint);