heater/stirrer: zero the setpoint on every disconnect, not just explicit ones

A comm-error/timeout-triggered disconnect left power_soll/power_actor
(heater) or speed (stirrer) untouched, so a later reconnect - or the
closed-loop TC, which keeps computing y regardless of connection state -
could immediately resume driving the device at whatever it was doing
before the outage. HeaterTask.disconnect()/StirrerTask.disconnect() now
centralize disconnect + zero-setpoint and are used for the explicit
Disconnect message, the per-tick comm-error path, and the outer
unexpected-error recovery path alike.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EU3NTwLygh8jkrnqPoHNXF

tasks/heater.py

@@ -55,6 +55,20 @@ class HeaterTask(ATask):
 			self._on_closed_loop_changed(True)
 		asyncio.create_task(self.send({'ClosedLoop': True}))
 
+	def disconnect(self):
+		"""Disconnects the device and zeroes its setpoint, so a later
+		reconnect (whether from an explicit Connect or an auto-reconnect)
+		never resumes at a stale power. Used for every disconnect - a
+		user-requested Disconnect, a comm-error timeout, and the
+		unexpected-exception recovery path alike - not just the explicit
+		one, since power_actor otherwise keeps whatever the TC last
+		computed (which can be stale/wound-up from before the outage) and
+		would be re-applied on the very next tick after reconnecting."""
+		self.device.disconnect()
+		self.power_soll = 0
+		self.power_actor = 0
+		self.power_set_changed(0)
+
 	def actor(self, y):
 		self.power_actor = max(0, self.device.get_power_max() * y)
 
@@ -78,9 +92,7 @@ class HeaterTask(ATask):
 					self.device.activate(True)
 			elif pair[0] == 'Disconnect':
 				self.device.activate(False)
-				self.device.disconnect()
+				self.disconnect()
-				self.power_soll = 0
-				self.power_set_changed(0)
 			elif 'Power' in pair[0]:
 				self.power_soll = pair[1]
 
@@ -167,12 +179,12 @@ class HeaterTask(ATask):
 							self.device.process()
 						except Exception as e:
 							print(f"HeaterTask: comm error, marking disconnected: {e}")
-							self.device.disconnect()
+							self.disconnect()
 						await asyncio.sleep(self.interval)
 			except Exception as e:
 				print(f"HeaterTask: unexpected error, recovering: {e}")
 				try:
-					self.device.disconnect()
+					self.disconnect()
 				except Exception:
 					pass
 				await asyncio.sleep(self.interval)

tasks/stirrer.py

@@ -37,6 +37,17 @@ class StirrerTask(ATask):
 		if self._on_connected_changed:
 			self._on_connected_changed(value)
 
+	def disconnect(self):
+		"""Disconnects the device and zeroes its speed setpoint, so a later
+		reconnect never resumes spinning at whatever speed was last set.
+		Used for every disconnect - a user-requested Disconnect, a
+		comm-error timeout, and the unexpected-exception recovery path
+		alike - not just the explicit one, since self.device.speed
+		otherwise still holds the old value and the duty-cycle pulsing in
+		AStirrer.process() re-sends it on the next isOn transition."""
+		self.device.disconnect()
+		self.device.set_speed(0.0)
+
 	async def recv(self, data):
 		for pair in data.items():
 			if pair[0] == 'Connect':
@@ -44,8 +55,7 @@ class StirrerTask(ATask):
 					self.device.activate(True)
 			elif pair[0] == 'Disconnect':
 				self.device.activate(False)
-				self.device.disconnect()
+				self.disconnect()
-				self.device.set_speed(0.0)
 			elif 'Speed' in pair[0]:
 				self.device.set_speed(pair[1])
 
@@ -79,12 +89,12 @@ class StirrerTask(ATask):
 							self.device.process()
 						except Exception as e:
 							print(f"StirrerTask: comm error, marking disconnected: {e}")
-							self.device.disconnect()
+							self.disconnect()
 						await asyncio.sleep(self.interval)
 			except Exception as e:
 				print(f"StirrerTask: unexpected error, recovering: {e}")
 				try:
-					self.device.disconnect()
+					self.disconnect()
 				except Exception:
 					pass
 				await asyncio.sleep(self.interval)