Add the duty cycle as a readable parameter via Serial.

CHANGELOG.md

+# CHANGELOG

README.md

@@ -3,6 +3,29 @@
 Sketches for Arduinos & Co.
 
 You can use this repository as the arduino sketchbook in the IDE.
+For that reason, the sketches (`ino` files) have the be in a folder of the same name.
+
+## Good practices
+
+* Add a `CHANGELOG.md` file for each arduino sketch.
+* Whenever you do a change, change the version string in that file according to [semantic versioning](https://semver.org/): Major.Minor.Patch.
+* If a sketch allows serial communication, you should be able to read the currently installed sketch.
+  Several programs use `v\n` to request the version.
+  The version should contain the Filename at compilation, the version, and the compilation date (for cross referencing a not mentioned change).
+  For that, you can use the following lines:
+  ```
+  // Top of the file
+  const String version = "1.3.0"; // Version of this script. Filename is added before, date of compilation afterwards.
+
+  // wherever serial communication is handled
+  Serial.print(__FILE__);  // file name at compilation time
+  Serial.print(" ");
+  Serial.print(version);  // the version string
+  Serial.print(" ");
+  Serial.print(__DATE__);  // compilation date
+  Serial.println();
+  ```
+
 
 
 # List of sketches with their functions
@@ -52,7 +75,7 @@ Schaltet die Shutter des Quanta-Rays.
 
 ## TemperatureController
 
-Kontrolliert die Temperatur mittels Ventilsteuerung und kann einerseits Messwerte (wie *ReadSensors*) ausgeben, andererseits können Parameter (Solltemperatur & Co.) eingestellt werden.
+Kontrolliert die Temperatur (oder andere Größe) mittels Schaltung von binären Steuerelementen (Ventil auf/zu) und kann einerseits Messwerte (wie *ReadSensors*) ausgeben, andererseits können Parameter (Solltemperatur & Co.) eingestellt werden.
 
 Es ist eine deutlich verbesserte Variante des *LegacyTemperatureController*.
 

TemperatureController/CHANGELOG.md

+# CHANGELOG
+
+## 1.3.0
+
+### Added
+
+* Add the duty cycle (in per mille) as a global variable (clamped to 0 to 1000) readable via debug.

TemperatureController/TemperatureController.ino

@@ -9,7 +9,7 @@
 */
 
 //**        CONSTANTS PARAMETERS  change for your application     **//
-const String version = "1.2.3"; // Version of this script. Filename is added before, date of compilation afterwards.
+const String version = "1.3.0"; // Version of this script. Filename is added before, date of compilation afterwards.
 
 const int cyclePeriod = 1; //program cycle period in s
 const int controlPin = 11; //Pin by which the control unit is controlled (11 or 12)
@@ -69,13 +69,14 @@ RunningAverage average5(averaging); //generate running average variable
 unsigned long nextCycle = 3000; //set starting values for an initial delay of some seconds to prevent racing conditions on start
 unsigned long nextOff = 0; // When to disable the control for the next time
 
+
 //******************************PID-CONTROL*****************************************
 // Werte werden aus EEPROM gelesen
 float setpoint; // setpoint for the temperature = 36°C
 float PIDKp; //Wert für die PID Regelung (Proportional-Teil)
 float PIDKi; //Wert für die PID Regelung (Integral-Teil)
 float integral; //Wert für die PID Integralteil
-
+float duty_cycle; //Current duty cycle in per mille
 
 int controller = 1;  // controller mode: 0 = off, 1 = on
 
@@ -214,6 +215,8 @@ void loop(){
         Serial.print(PIDKi);
         Serial.print(", setpoint: ");
         Serial.print(setpoint);
+        Serial.print(", duty cycle: ");
+        Serial.print(duty_cycle);
         Serial.println();
         break;
       case 'v':  // Send Version
@@ -248,7 +251,7 @@ void loop(){
     }
   }
 
-  // Control temperature, if desired
+  // Start new pulse, calculating the duty cycle and pulse length
   if ( millis() >= nextCycle ){
     if (controller > 0){
       calculatePID();
@@ -256,6 +259,7 @@ void loop(){
     nextCycle += cyclePeriod * 1000;
   }
 
+  // stop the pulse, if pulse length elapsed
   if ( millis() >= nextOff && nextOff > 0){
     enable_control(false);
   }
@@ -305,8 +309,10 @@ void sendSensorDataAverage(){
 
 
 void calculatePID(){
-  // Calculate the PID signal
+  // Calculate the PID signal and duty cycle, and start a new pulse
   float error = setpoint - average0.getAverage();
+
+  // calculate integral part, clamp it between 0 and 1000
   integral += PIDKi * error;
   if (integral > 1000){
     integral = 1000;
@@ -314,25 +320,28 @@ void calculatePID(){
   else if (integral < 0){
     integral = 0;
   }
-  float pid = PIDKp * error + integral;
-  if (pid < 0){
+
+  // caclulate the duty cycle, clamp it between 0 and 1000
+  duty_cycle = PIDKp * error + integral;
+  if (duty_cycle < 0){
     nextOff = 0;
+    duty_cycle = 0;
     enable_control( false );
   }
   else {
-    nextOff = millis() + cyclePeriod * pid;
+    // start a new pulse and set the pulse length
+    nextOff = millis() + cyclePeriod * duty_cycle;
     enable_control( true );
   }
+  if (duty_cycle > 1000){
+    duty_cycle = 1000;
+  }
 }
 
 void enable_control(const boolean enabled){
   //Enable or disable the control (relay, valve...)
-  if ( enabled ){
-    digitalWrite(controlPin, HIGH);
-    digitalWrite(indicatorPin, HIGH);
-  }
-  else {
-    digitalWrite(controlPin, LOW);
-    digitalWrite(indicatorPin, LOW);
+  if (digitalRead(controlPin) != enabled){
+    digitalWrite(controlPin, enabled);
+    digitalWrite(indicatorPin, enabled);
   }
 }