fan: Add support for heater_fan objects

Add support for fans designed to cool the components of an extruder or
heater.

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>

config/example.cfg

@@ -322,3 +322,17 @@ max_z_accel: 30
 #   centripetal velocity cornering algorithm. A larger number will
 #   permit higher "cornering speeds" at the junction of two moves. The
 #   default is 0.02mm.
+
+# Heater cooling fans (one may define any number of sections with a
+# "heater_fan" prefix). A "heater fan" is a fan that will be enabled
+# whenever its associated heater is active.
+#[heater_fan my_nozzle_fan]
+# See the "fan" section for fan configuration parameters.
+#pin: ar7
+# The remaining variables are specific to heater_fan.
+#heater: extruder
+#   Name of the config section defining the heater that this fan is
+#   associated with.  The default is "extruder".
+#heater_temp: 50.0
+#   A temperature (in Celsius) that the heater must drop below before
+#   the fan is disabled. The default is 50 Celsius.

config/makergear-m2-2012.cfg

@@ -72,11 +72,14 @@ max_temp: 100
 [fan]
 pin: PH5
 
+[heater_fan nozzle_fan]
+pin: PH3
+max_power: 0.61
+hard_pwm: 1
+
 [mcu]
 serial: /dev/ttyACM0
 custom:
-  # Nozzle fan
-  set_pwm_out pin=PH3 cycle_ticks=1 value=155
   # Turn off yellow led
   set_digital_out pin=PB7 value=0
   # Stepper micro-step pins

klippy/extruder.py

@@ -243,3 +243,13 @@ def get_printer_extruders(printer):
             break
         out.append(extruder)
     return out
+
+def get_printer_heater(printer, name):
+    if name == 'heater_bed':
+        return printer.objects.get(name)
+    if name == 'extruder':
+        name = 'extruder0'
+    extruder = printer.objects.get(name)
+    if extruder is None:
+        return None
+    return extruder.get_heater()

klippy/fan.py

@@ -1,9 +1,11 @@
 # Printer fan support
 #
-# Copyright (C) 2016  Kevin O'Connor <kevin@koconnor.net>
+# Copyright (C) 2016,2017  Kevin O'Connor <kevin@koconnor.net>
 #
 # This file may be distributed under the terms of the GNU GPLv3 license.
 
+import extruder
+
 FAN_MIN_TIME = 0.1
 PWM_CYCLE_TIME = 0.010
 
@@ -16,12 +18,10 @@ class PrinterFan:
         pin = config.get('pin')
         hard_pwm = config.getint('hard_pwm', 0)
         self.mcu_fan = printer.mcu.create_pwm(pin, PWM_CYCLE_TIME, hard_pwm, 0.)
-    # External commands
-    def set_speed(self, print_time, value):
+    def set_pwm(self, mcu_time, value):
         value = max(0., min(self.max_power, value))
         if value == self.last_fan_value:
             return
-        mcu_time = self.mcu_fan.print_to_mcu_time(print_time)
         mcu_time = max(self.last_fan_time + FAN_MIN_TIME, mcu_time)
         if (value and value < self.max_power
             and not self.last_fan_value and self.kick_start_time):
@@ -31,7 +31,34 @@ class PrinterFan:
         self.mcu_fan.set_pwm(mcu_time, value)
         self.last_fan_time = mcu_time
         self.last_fan_value = value
+    # External commands
+    def set_speed(self, print_time, value):
+        mcu_time = self.mcu_fan.print_to_mcu_time(print_time)
+        self.set_pwm(mcu_time, value)
+
+class PrinterHeaterFan:
+    def __init__(self, printer, config):
+        self.fan = PrinterFan(printer, config)
+        heater = config.get("heater", "extruder0")
+        self.heater = extruder.get_printer_heater(printer, heater)
+        if self.heater is None:
+            raise config.error("Unknown heater '%s'" % (heater,))
+        self.heater_temp = config.getfloat("heater_temp", 50.0)
+        printer.reactor.register_timer(self.callback, printer.reactor.NOW)
+    def callback(self, eventtime):
+        current_temp, target_temp = self.heater.get_temp()
+        if not current_temp and not target_temp and not self.fan.last_fan_time:
+            # Printer still starting
+            return eventtime + 1.
+        power = 0.
+        if target_temp or current_temp > self.heater_temp:
+            power = 1.
+        mcu_time = self.fan.mcu_fan.system_to_mcu_time(eventtime + FAN_MIN_TIME)
+        self.fan.set_pwm(mcu_time, power)
+        return eventtime + 1.
 
 def add_printer_objects(printer, config):
     if config.has_section('fan'):
         printer.add_object('fan', PrinterFan(printer, config.getsection('fan')))
+    for s in config.get_prefix_sections('heater_fan '):
+        printer.add_object(s.section, PrinterHeaterFan(printer, s))

klippy/klippy.py

@@ -107,6 +107,9 @@ class ConfigWrapper:
         return ConfigWrapper(self.printer, section)
     def has_section(self, section):
         return self.printer.fileconfig.has_section(section)
+    def get_prefix_sections(self, prefix):
+        return [self.getsection(s) for s in self.printer.fileconfig.sections()
+                if s.startswith(prefix)]
 
 class ConfigLogger():
     def __init__(self, cfg, bglogger):