Removal of functional range constraint

Also lined up the >> 1 and / 2 mentioned earlier in the unconstrained I term issue,

Marlin/temperature.cpp

   #endif
 
   float Temperature::pid_error[HOTENDS];
-  bool Temperature::pid_reset[HOTENDS];
 #endif
 
 #if ENABLED(PIDTEMPBED)
 #endif
 
 #if HAS_PID_HEATING
-
   void Temperature::PID_autotune(float temp, int hotend, int ncycles, bool set_result/*=false*/) {
     float input = 0.0;
     int cycles = 0;
 }
 
 #if HAS_AUTO_FAN
-
   void Temperature::checkExtruderAutoFans() {
     const int8_t fanPin[] = { EXTRUDER_0_AUTO_FAN_PIN, EXTRUDER_1_AUTO_FAN_PIN, EXTRUDER_2_AUTO_FAN_PIN, EXTRUDER_3_AUTO_FAN_PIN };
     const int fanBit[] = {
   #endif
   float pid_output;
   #if ENABLED(PIDTEMP)
-    #if DISABLED(PID_OPENLOOP)
+    #if ENABLED(PID_OPENLOOP)
+      pid_output = constrain(target_temperature[HOTEND_INDEX], 0, PID_MAX);
+    #else
       pid_error[HOTEND_INDEX] = target_temperature[HOTEND_INDEX] - current_temperature[HOTEND_INDEX];
       dTerm[HOTEND_INDEX] = K2 * PID_PARAM(Kd, HOTEND_INDEX) * (current_temperature[HOTEND_INDEX] - temp_dState[HOTEND_INDEX]) + K1 * dTerm[HOTEND_INDEX];
       temp_dState[HOTEND_INDEX] = current_temperature[HOTEND_INDEX];
-      if (pid_error[HOTEND_INDEX] > PID_FUNCTIONAL_RANGE) {
-        pid_output = BANG_MAX;
-        pid_reset[HOTEND_INDEX] = true;
-      }
-      else if (pid_error[HOTEND_INDEX] < -(PID_FUNCTIONAL_RANGE) || target_temperature[HOTEND_INDEX] == 0) {
+      if (target_temperature[HOTEND_INDEX] == 0) {
         pid_output = 0;
-        pid_reset[HOTEND_INDEX] = true;
+        temp_iState[HOTEND_INDEX] = 0.0;
       }
       else {
-        if (pid_reset[HOTEND_INDEX]) {
-          temp_iState[HOTEND_INDEX] = 0.0;
-          pid_reset[HOTEND_INDEX] = false;
-        }
         pTerm[HOTEND_INDEX] = PID_PARAM(Kp, HOTEND_INDEX) * pid_error[HOTEND_INDEX];
         temp_iState[HOTEND_INDEX] += pid_error[HOTEND_INDEX];
         iTerm[HOTEND_INDEX] = PID_PARAM(Ki, HOTEND_INDEX) * temp_iState[HOTEND_INDEX];
           pid_output = 0;
         }
       }
-    #else
-      pid_output = constrain(target_temperature[HOTEND_INDEX], 0, PID_MAX);
     #endif //PID_OPENLOOP
 
     #if ENABLED(PID_DEBUG)

Marlin/temperature.h

       #endif
 
       static float pid_error[HOTENDS];
-      static bool pid_reset[HOTENDS];
     #endif
 
     #if ENABLED(PIDTEMPBED)