From ba84295ec5224e96e79aef3d1df147985de351a8 Mon Sep 17 00:00:00 2001
From: Astro <astro@spaceboyz.net>
Date: Fri, 18 Sep 2020 00:09:30 +0200
Subject: [PATCH] reconnect the pid controller

---
 src/channel_state.rs | 11 ++++++-----
 src/channels.rs      | 21 ++++++++-------------
 src/main.rs          |  4 ++--
 src/pid.rs           |  5 +++++
 4 files changed, 21 insertions(+), 20 deletions(-)

diff --git a/src/channel_state.rs b/src/channel_state.rs
index 7cc5def..a25bd24 100644
--- a/src/channel_state.rs
+++ b/src/channel_state.rs
@@ -7,7 +7,7 @@ use uom::si::{
     },
     electric_potential::volt,
     electrical_resistance::ohm,
-    temperature_interval::kelvin,
+    thermodynamic_temperature::degree_celsius,
 };
 use crate::{
     ad7172,
@@ -51,10 +51,11 @@ impl ChannelState {
     }
 
     /// Update PID state on ADC input, calculate new DAC output
-    pub fn update_pid(&mut self) {
-        // Update PID controller
-        // self.pid.update(self.get_temperature().unwrap().get::<kelvin>())
-        // TODO: add output field
+    pub fn update_pid(&mut self) -> Option<f64> {
+        let temperature = self.get_temperature()?
+            .get::<degree_celsius>();
+        let pid_output = self.pid.update(temperature);
+        Some(pid_output)
     }
 
     pub fn get_adc(&self) -> Option<ElectricPotential> {
diff --git a/src/channels.rs b/src/channels.rs
index 39b9cb5..196c927 100644
--- a/src/channels.rs
+++ b/src/channels.rs
@@ -70,21 +70,16 @@ impl Channels {
         self.adc.data_ready().unwrap().map(|channel| {
             let data = self.adc.read_data().unwrap();
 
-            let dac_value = {
-                let state = self.channel_state(channel);
-                state.update(instant, data);
-                let pid_output = state.update_pid();
+            let state = self.channel_state(channel);
 
-                if state.pid_engaged {
-                    Some(pid_output)
-                } else {
-                    None
+            state.update(instant, data);
+            match state.update_pid() {
+                Some(pid_output) if state.pid_engaged => {
+                    log::info!("PID: {:.3} A", pid_output);
+                    // Forward PID output to i_set DAC
+                    self.set_i(channel.into(), ElectricCurrent::new::<ampere>(pid_output));
                 }
-            };
-            if let Some(dac_value) = dac_value {
-                // Forward PID output to i_set DAC
-                // TODO:
-                // self.set_dac(channel.into(), ElectricPotential::new::<volt>(dac_value));
+                _ => {}
             }
 
             channel
diff --git a/src/main.rs b/src/main.rs
index e97136e..27e83ff 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -200,7 +200,7 @@ fn main() -> ! {
                                         let state = channels.channel_state(channel);
                                         let _ = writeln!(socket, "PID settings for channel {}", channel);
                                         let pid = &state.pid;
-                                        let _ = writeln!(socket, "- target={:.4}", pid.target);
+                                        let _ = writeln!(socket, "- target={:.4} °C", pid.target);
                                         macro_rules! show_pid_parameter {
                                             ($p: tt) => {
                                                 let _ = writeln!(
@@ -217,7 +217,7 @@ fn main() -> ! {
                                         show_pid_parameter!(output_min);
                                         show_pid_parameter!(output_max);
                                         if let Some(last_output) = pid.last_output {
-                                            let _ = writeln!(socket, "- last_output={:.4}", last_output);
+                                            let _ = writeln!(socket, "- last_output={:.3} A", last_output);
                                         }
                                         let _ = writeln!(socket, "");
                                     }
diff --git a/src/pid.rs b/src/pid.rs
index b17dfff..83878d8 100644
--- a/src/pid.rs
+++ b/src/pid.rs
@@ -44,10 +44,13 @@ impl Controller {
     }
 
     pub fn update(&mut self, input: f64) -> f64 {
+        // error
         let error = self.target - input;
 
+        // partial
         let p = self.parameters.kp * error;
 
+        //integral
         self.integral += error;
         if self.integral < self.parameters.integral_min {
             self.integral = self.parameters.integral_min;
@@ -57,12 +60,14 @@ impl Controller {
         }
         let i = self.parameters.ki * self.integral;
 
+        // derivative
         let d = match self.last_input {
             None => 0.0,
             Some(last_input) => self.parameters.kd * (last_input - input)
         };
         self.last_input = Some(input);
 
+        // output
         let mut output = p + i + d;
         if output < self.parameters.output_min {
             output = self.parameters.output_min;