Single PID dataset with HOTENDS == 1

Marlin/temperature.h

 
     #if ENABLED(PIDTEMP)
 
-      #if ENABLED(PID_PARAMS_PER_HOTEND)
+      #if ENABLED(PID_PARAMS_PER_HOTEND) && HOTENDS > 1
 
         static float Kp[HOTENDS], Ki[HOTENDS], Kd[HOTENDS];
         #if ENABLED(PID_ADD_EXTRUSION_RATE)
           static float Kc[HOTENDS];
         #endif
-        #define PID_PARAM(param, e) Temperature::param[e]
+        #define PID_PARAM(param, h) Temperature::param[h]
 
       #else
 
         #if ENABLED(PID_ADD_EXTRUSION_RATE)
           static float Kc;
         #endif
-        #define PID_PARAM(param, e) Temperature::param
+        #define PID_PARAM(param, h) Temperature::param
 
       #endif // PID_PARAMS_PER_HOTEND