temperature_fan: Fix. Temperature fan min speed should be used (#1405)

Signed-off-by: Douglas Hammond <wizhippo@gmail.com>

config/example-extras.cfg

@@ -626,20 +626,20 @@
 #   The default is 1.0.
 #min_speed: 0.3
 #   The minimum fan speed (expressed as a value from 0.0 to 1.0) that
-#   the fan will be set to when the sensor temperature is the set
+#   the fan will be set to for PID temperature fans.
-#   value.  The default is 0.3.
+#   The default is 0.3.
 #control: watermark
 #   Control algorithm (either watermark or pid). This parameter must
 #   be provided.
 #pid_Kp: 40
 #   Kp is the "proportional" constant for the pid. This parameter must
-#   be provided for PID heaters.
+#   be provided for PID temperature fans.
 #pid_Ki: 0.2
 #   Ki is the "integral" constant for the pid. This parameter must be
-#   provided for PID heaters.
+#   provided for PID temperature fans.
 #pid_Kd: 0.1
 #   Kd is the "derivative" constant for the pid. This parameter must
-#   be provided for PID heaters.
+#   be provided for PID temperature fans.
 #pid_deriv_time: 2.0
 #   A time value (in seconds) over which the derivative in the pid
 #   will be smoothed to reduce the impact of measurement noise. The

docs/Config_Changes.md

@@ -6,6 +6,10 @@ All dates in this document are approximate.
 
 # Changes
 
+20190328: The min_speed value in [temperature_fan] config
+will now be respected and the fan will always run at this
+speed or higher in PID mode.
+
 20190322: The default value for "driver_HEND" in [tmc2660] config
 sections was changed from 6 to 3. The "driver_VSENSE" field was
 removed (it is now automatically calculated from run_current).

klippy/extras/temperature_fan.py

@@ -15,7 +15,6 @@ class TemperatureFan:
         self.name = config.get_name().split()[1]
         self.printer = config.get_printer()
         self.fan = fan.PrinterFan(config, default_shutdown_speed=1.)
-        self.mcu = self.fan.mcu_fan.get_mcu()
         self.min_temp = config.getfloat('min_temp', minval=KELVIN_TO_CELCIUS)
         self.max_temp = config.getfloat('max_temp', above=self.min_temp)
         self.sensor = self.printer.lookup_object('heater').setup_sensor(config)
@@ -36,8 +35,10 @@ class TemperatureFan:
         self.next_speed_time = 0.
         self.last_speed_value = 0.
     def set_speed(self, read_time, value):
-        if value < self.min_speed:
+        if value <= 0.:
             value = 0.
+        elif value < self.min_speed:
+            value = self.min_speed
         if self.target_temp <= 0.:
             value = 0.
         if ((read_time < self.next_speed_time or not self.last_speed_value)
@@ -53,6 +54,10 @@ class TemperatureFan:
         self.control.temperature_callback(read_time, temp)
     def get_temp(self, eventtime):
         return self.last_temp, self.target_temp
+    def get_min_speed(self):
+        return self.min_speed
+    def get_max_speed(self):
+        return self.max_speed
 
 ######################################################################
 # Bang-bang control algo
@@ -64,17 +69,18 @@ class ControlBangBang:
         self.max_delta = config.getfloat('max_delta', 2.0, above=0.)
         self.heating = False
     def temperature_callback(self, read_time, temp):
+        current_temp, target_temp = self.temperature_fan.get_temp(read_time)
         if (self.heating
-            and temp >= self.temperature_fan.target_temp+self.max_delta):
+            and temp >= target_temp+self.max_delta):
             self.heating = False
         elif (not self.heating
-              and temp <= self.temperature_fan.target_temp-self.max_delta):
+              and temp <= target_temp-self.max_delta):
             self.heating = True
         if self.heating:
             self.temperature_fan.set_speed(read_time, 0.)
         else:
             self.temperature_fan.set_speed(read_time,
-                                           self.temperature_fan.max_speed)
+                                           self.temperature_fan.get_max_speed())
 
 ######################################################################
 # Proportional Integral Derivative (PID) control algo
@@ -90,14 +96,15 @@ class ControlPID:
         self.Ki = config.getfloat('pid_Ki') / PID_PARAM_BASE
         self.Kd = config.getfloat('pid_Kd') / PID_PARAM_BASE
         self.min_deriv_time = config.getfloat('pid_deriv_time', 2., above=0.)
-        imax = config.getfloat('pid_integral_max', temperature_fan.max_speed,
+        imax = config.getfloat('pid_integral_max',
-                               minval=0.)
+                               self.temperature_fan.get_max_speed(), minval=0.)
         self.temp_integ_max = imax / self.Ki
         self.prev_temp = AMBIENT_TEMP
         self.prev_temp_time = 0.
         self.prev_temp_deriv = 0.
         self.prev_temp_integ = 0.
     def temperature_callback(self, read_time, temp):
+        current_temp, target_temp = self.temperature_fan.get_temp(read_time)
         time_diff = read_time - self.prev_temp_time
         # Calculate change of temperature
         temp_diff = temp - self.prev_temp
@@ -107,14 +114,15 @@ class ControlPID:
             temp_deriv = (self.prev_temp_deriv * (self.min_deriv_time-time_diff)
                           + temp_diff) / self.min_deriv_time
         # Calculate accumulated temperature "error"
-        temp_err = self.temperature_fan.target_temp - temp
+        temp_err = target_temp - temp
         temp_integ = self.prev_temp_integ + temp_err * time_diff
         temp_integ = max(0., min(self.temp_integ_max, temp_integ))
         # Calculate output
         co = self.Kp*temp_err + self.Ki*temp_integ - self.Kd*temp_deriv
-        bounded_co = max(0., min(self.temperature_fan.max_speed, co))
+        bounded_co = max(0., min(self.temperature_fan.get_max_speed(), co))
         self.temperature_fan.set_speed(
-            read_time, self.temperature_fan.max_speed - bounded_co)
+            read_time, max(self.temperature_fan.get_min_speed(),
+                           self.temperature_fan.get_max_speed() - bounded_co))
         # Store state for next measurement
         self.prev_temp = temp
         self.prev_temp_time = read_time