Copter: rangefinder.enabled false if no range finders are configured

ArduCopter/Copter.h

@@ -177,7 +177,7 @@ private:
         int16_t alt_cm;     // tilt compensated altitude (in cm) from rangefinder
         uint32_t last_healthy_ms;
         LowPassFilterFloat alt_cm_filt; // altitude filter
-    } rangefinder_state = { true, false, 0, 0 };
+    } rangefinder_state = { false, false, 0, 0 };
 #endif
 
     AP_RPM rpm_sensor;

ArduCopter/sensors.cpp

@@ -31,6 +31,7 @@ void Copter::init_rangefinder(void)
 #if RANGEFINDER_ENABLED == ENABLED
    rangefinder.init();
    rangefinder_state.alt_cm_filt.set_cutoff_frequency(RANGEFINDER_WPNAV_FILT_HZ);
+   rangefinder_state.enabled = (rangefinder.num_sensors() >= 1);
 #endif
 }
 
@@ -68,6 +69,7 @@ void Copter::read_rangefinder(void)
     wp_nav.set_rangefinder_alt(rangefinder_state.enabled, rangefinder_state.alt_healthy, rangefinder_state.alt_cm_filt.get());
 
 #else
+    rangefinder_state.enabled = false;
     rangefinder_state.alt_healthy = false;
     rangefinder_state.alt_cm = 0;
 #endif

ArduCopter/switches.cpp

@@ -348,7 +348,7 @@ void Copter::do_aux_switch_function(int8_t ch_function, uint8_t ch_flag)
         case AUXSW_RANGEFINDER:
             // enable or disable the rangefinder
 #if RANGEFINDER_ENABLED == ENABLED
-            if (ch_flag == AUX_SWITCH_HIGH) {
+            if ((ch_flag == AUX_SWITCH_HIGH) && (rangefinder.num_sensors() >= 1)) {
                 rangefinder_state.enabled = true;
             }else{
                 rangefinder_state.enabled = false;