temp_mon: fix limits not effective at stable temp

- previously, temp is stable, temp limits are not checked

src/main.rs

@@ -160,7 +160,6 @@ fn main() -> ! {
                     thermostat.update_pid();
                     if thermostat.get_temp_mon_status().over_temp_alarm {
                         laser.power_down();
-                        thermostat.set_pid_engaged(false);
                         thermostat.power_down();
                     }
 

src/thermostat/temp_mon.rs

@@ -32,6 +32,7 @@ pub struct TempMon {
     state: State,
     count: u32,
     is_set_point_changed: bool,
+    is_limit_changed: bool,
 }
 
 impl Default for TempMon {
@@ -48,6 +49,7 @@ impl Default for TempMon {
             count: 0,
             // stable_temp_count: 0,
             is_set_point_changed: false,
+            is_limit_changed: false,
         }
     }
 }
@@ -68,6 +70,7 @@ impl TempMon {
 
     pub fn set_upper_limit(&mut self, upper_limit: ThermodynamicTemperature) {
         self.upper_limit = upper_limit;
+        self.is_limit_changed = true;
     }
 
     pub fn get_upper_limit(&mut self) -> ThermodynamicTemperature {
@@ -76,6 +79,7 @@ impl TempMon {
 
     pub fn set_lower_limit(&mut self, lower_limit: ThermodynamicTemperature) {
         self.lower_limit = lower_limit;
+        self.is_limit_changed = true;
     }
 
     pub fn get_lower_limit(&mut self) -> ThermodynamicTemperature {
@@ -129,11 +133,9 @@ impl TempMon {
                 }
             }
             State::PidStartUp | State::PidStable => {
-                let is_over_temp: bool;
+                let mut is_over_temp = temp > self.upper_limit || temp < self.lower_limit;
-                if self.state == State::PidStartUp {
+                if self.state != State::PidStartUp {
-                    is_over_temp = temp > self.upper_limit || temp < self.lower_limit;
+                    is_over_temp = is_over_temp || (temp.value - self.set_point.value).abs() > 0.5;
-                } else {
-                    is_over_temp = (temp.value - self.set_point.value).abs() > 0.5;
                 }
 
                 let is_within_spec: bool = (temp.value - self.set_point.value).abs() < 0.001;
@@ -163,6 +165,12 @@ impl TempMon {
                     } else if self.is_set_point_changed {
                         self.is_set_point_changed = false;
                         self.state = State::PidStartUp;
+                    } else if self.is_limit_changed {
+                        self.is_limit_changed = false;
+                        if is_over_temp {
+                            self.state = State::PidStartUp;
+                            self.count = 0;
+                        }
                     } else if self.status.status == TempStatusEnum::Stable {
                         self.state = State::PidStable;
                     } else if !pid_engaged {