heater: Do not require target temperature be above min_extrude_temp

Only disable the extruder if the last measured temperature is below
the minimum extrude temperature setting.  Verifying the target
temperature is not necessary, and it can incorrectly prevent some
valid moves.  It's not uncommon for scripts to retract filament
immiedietly after setting the extruder temperature to zero.

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

1 files changed, 2 insertions, 5 deletions

diff --git a/klippy/heater.py b/klippy/heater.py
index bef1f48c..06bc0cd1 100644
--- a/klippy/heater.py
+++ b/klippy/heater.py
@@ -29,7 +29,7 @@ class PrinterHeater:
         self.thermistor_c = Thermistors.get(config.get('thermistor_type'))
         self.pullup_r = config.getfloat('pullup_resistor', 4700.)
         self.min_extrude_temp = config.getfloat('min_extrude_temp', 170.)
-        self.can_extrude = self.min_extrude_temp <= 0.
+        self.can_extrude = (self.min_extrude_temp <= 0.)
         self.lock = threading.Lock()
         self.last_temp = 0.
         self.last_temp_time = 0.
@@ -91,16 +91,13 @@ class PrinterHeater:
         with self.lock:
             self.last_temp = temp
             self.last_temp_time = read_time
-            self.can_extrude = (self.last_temp >= self.min_extrude_temp
-                                and self.target_temp >= self.min_extrude_temp)
+            self.can_extrude = (temp >= self.min_extrude_temp)
             self.control.adc_callback(read_time, temp)
         #logging.debug("temp: %.3f %f = %f" % (read_time, read_value, temp))
     # External commands
     def set_temp(self, print_time, degrees):
         with self.lock:
             self.target_temp = degrees
-            if self.target_temp < self.min_extrude_temp:
-                self.can_extrude = False
     def get_temp(self):
         with self.lock:
             return self.last_temp, self.target_temp