diff --git a/ArduPlane/afs_plane.cpp b/ArduPlane/afs_plane.cpp
index b4c72291da..59cf2b9a36 100644
--- a/ArduPlane/afs_plane.cpp
+++ b/ArduPlane/afs_plane.cpp
@@ -35,17 +35,17 @@ void AP_AdvancedFailsafe_Plane::terminate_vehicle(void)
         SRV_Channels::set_output_scaled(SRV_Channel::k_elevator, SERVO_MAX);
         if (plane.have_reverse_thrust()) {
             // configured for reverse thrust, use TRIM
-            SRV_Channels::set_output_limit(SRV_Channel::k_throttle, SRV_Channel::SRV_CHANNEL_LIMIT_TRIM);
-            SRV_Channels::set_output_limit(SRV_Channel::k_throttleLeft, SRV_Channel::SRV_CHANNEL_LIMIT_TRIM);
-            SRV_Channels::set_output_limit(SRV_Channel::k_throttleRight, SRV_Channel::SRV_CHANNEL_LIMIT_TRIM);
+            SRV_Channels::set_output_limit(SRV_Channel::k_throttle, SRV_Channel::Limit::TRIM);
+            SRV_Channels::set_output_limit(SRV_Channel::k_throttleLeft, SRV_Channel::Limit::TRIM);
+            SRV_Channels::set_output_limit(SRV_Channel::k_throttleRight, SRV_Channel::Limit::TRIM);
         } else {
             // use MIN
-            SRV_Channels::set_output_limit(SRV_Channel::k_throttle, SRV_Channel::SRV_CHANNEL_LIMIT_MIN);
-            SRV_Channels::set_output_limit(SRV_Channel::k_throttleLeft, SRV_Channel::SRV_CHANNEL_LIMIT_MIN);
-            SRV_Channels::set_output_limit(SRV_Channel::k_throttleRight, SRV_Channel::SRV_CHANNEL_LIMIT_MIN);
+            SRV_Channels::set_output_limit(SRV_Channel::k_throttle, SRV_Channel::Limit::MIN);
+            SRV_Channels::set_output_limit(SRV_Channel::k_throttleLeft, SRV_Channel::Limit::MIN);
+            SRV_Channels::set_output_limit(SRV_Channel::k_throttleRight, SRV_Channel::Limit::MIN);
         }
-        SRV_Channels::set_output_limit(SRV_Channel::k_manual, SRV_Channel::SRV_CHANNEL_LIMIT_TRIM);
-        SRV_Channels::set_output_limit(SRV_Channel::k_none, SRV_Channel::SRV_CHANNEL_LIMIT_TRIM);
+        SRV_Channels::set_output_limit(SRV_Channel::k_manual, SRV_Channel::Limit::TRIM);
+        SRV_Channels::set_output_limit(SRV_Channel::k_none, SRV_Channel::Limit::TRIM);
     }
 
     plane.servos_output();
@@ -59,24 +59,24 @@ void AP_AdvancedFailsafe_Plane::terminate_vehicle(void)
 void AP_AdvancedFailsafe_Plane::setup_IO_failsafe(void)
 {
     // all aux channels
-    SRV_Channels::set_failsafe_limit(SRV_Channel::k_flap_auto, SRV_Channel::SRV_CHANNEL_LIMIT_MAX);
-    SRV_Channels::set_failsafe_limit(SRV_Channel::k_flap, SRV_Channel::SRV_CHANNEL_LIMIT_MAX);
-    SRV_Channels::set_failsafe_limit(SRV_Channel::k_aileron, SRV_Channel::SRV_CHANNEL_LIMIT_MIN);
-    SRV_Channels::set_failsafe_limit(SRV_Channel::k_rudder, SRV_Channel::SRV_CHANNEL_LIMIT_MAX);
-    SRV_Channels::set_failsafe_limit(SRV_Channel::k_elevator, SRV_Channel::SRV_CHANNEL_LIMIT_MAX);
+    SRV_Channels::set_failsafe_limit(SRV_Channel::k_flap_auto, SRV_Channel::Limit::MAX);
+    SRV_Channels::set_failsafe_limit(SRV_Channel::k_flap, SRV_Channel::Limit::MAX);
+    SRV_Channels::set_failsafe_limit(SRV_Channel::k_aileron, SRV_Channel::Limit::MIN);
+    SRV_Channels::set_failsafe_limit(SRV_Channel::k_rudder, SRV_Channel::Limit::MAX);
+    SRV_Channels::set_failsafe_limit(SRV_Channel::k_elevator, SRV_Channel::Limit::MAX);
     if (plane.have_reverse_thrust()) {
         // configured for reverse thrust, use TRIM
-        SRV_Channels::set_failsafe_limit(SRV_Channel::k_throttle, SRV_Channel::SRV_CHANNEL_LIMIT_TRIM);
-        SRV_Channels::set_failsafe_limit(SRV_Channel::k_throttleLeft, SRV_Channel::SRV_CHANNEL_LIMIT_TRIM);
-        SRV_Channels::set_failsafe_limit(SRV_Channel::k_throttleRight, SRV_Channel::SRV_CHANNEL_LIMIT_TRIM);
+        SRV_Channels::set_failsafe_limit(SRV_Channel::k_throttle, SRV_Channel::Limit::TRIM);
+        SRV_Channels::set_failsafe_limit(SRV_Channel::k_throttleLeft, SRV_Channel::Limit::TRIM);
+        SRV_Channels::set_failsafe_limit(SRV_Channel::k_throttleRight, SRV_Channel::Limit::TRIM);
     } else {
         // normal throttle, use MIN
-        SRV_Channels::set_failsafe_limit(SRV_Channel::k_throttle, SRV_Channel::SRV_CHANNEL_LIMIT_MIN);
-        SRV_Channels::set_failsafe_limit(SRV_Channel::k_throttleLeft, SRV_Channel::SRV_CHANNEL_LIMIT_MIN);
-        SRV_Channels::set_failsafe_limit(SRV_Channel::k_throttleRight, SRV_Channel::SRV_CHANNEL_LIMIT_MIN);
+        SRV_Channels::set_failsafe_limit(SRV_Channel::k_throttle, SRV_Channel::Limit::MIN);
+        SRV_Channels::set_failsafe_limit(SRV_Channel::k_throttleLeft, SRV_Channel::Limit::MIN);
+        SRV_Channels::set_failsafe_limit(SRV_Channel::k_throttleRight, SRV_Channel::Limit::MIN);
     }
-    SRV_Channels::set_failsafe_limit(SRV_Channel::k_manual, SRV_Channel::SRV_CHANNEL_LIMIT_TRIM);
-    SRV_Channels::set_failsafe_limit(SRV_Channel::k_none, SRV_Channel::SRV_CHANNEL_LIMIT_TRIM);
+    SRV_Channels::set_failsafe_limit(SRV_Channel::k_manual, SRV_Channel::Limit::TRIM);
+    SRV_Channels::set_failsafe_limit(SRV_Channel::k_none, SRV_Channel::Limit::TRIM);
 
     if (plane.quadplane.available()) {
         // setup AP_Motors outputs for failsafe
diff --git a/ArduPlane/mode_fbwa.cpp b/ArduPlane/mode_fbwa.cpp
index 121d801ec0..0f165010d1 100644
--- a/ArduPlane/mode_fbwa.cpp
+++ b/ArduPlane/mode_fbwa.cpp
@@ -30,7 +30,7 @@ void ModeFBWA::update()
         // FBWA failsafe glide
         plane.nav_roll_cd = 0;
         plane.nav_pitch_cd = 0;
-        SRV_Channels::set_output_limit(SRV_Channel::k_throttle, SRV_Channel::SRV_CHANNEL_LIMIT_MIN);
+        SRV_Channels::set_output_limit(SRV_Channel::k_throttle, SRV_Channel::Limit::MIN);
     }
     if (plane.g.fbwa_tdrag_chan > 0) {
         // check for the user enabling FBWA taildrag takeoff mode
diff --git a/ArduPlane/radio.cpp b/ArduPlane/radio.cpp
index f30995cbc9..8f4df73dfb 100644
--- a/ArduPlane/radio.cpp
+++ b/ArduPlane/radio.cpp
@@ -41,7 +41,7 @@ void Plane::set_control_channels(void)
     }
 
     if (!arming.is_armed() && arming.arming_required() == AP_Arming::Required::YES_MIN_PWM) {
-        SRV_Channels::set_safety_limit(SRV_Channel::k_throttle, have_reverse_thrust()?SRV_Channel::SRV_CHANNEL_LIMIT_TRIM:SRV_Channel::SRV_CHANNEL_LIMIT_MIN);
+        SRV_Channels::set_safety_limit(SRV_Channel::k_throttle, have_reverse_thrust()?SRV_Channel::Limit::TRIM:SRV_Channel::Limit::MIN);
     }
 
     if (!quadplane.enable) {
@@ -79,15 +79,15 @@ void Plane::init_rc_out_main()
         SRV_Channels::set_trim_to_min_for(SRV_Channel::k_throttle);
     }
 
-    SRV_Channels::set_failsafe_limit(SRV_Channel::k_aileron, SRV_Channel::SRV_CHANNEL_LIMIT_TRIM);
-    SRV_Channels::set_failsafe_limit(SRV_Channel::k_elevator, SRV_Channel::SRV_CHANNEL_LIMIT_TRIM);
-    SRV_Channels::set_failsafe_limit(SRV_Channel::k_throttle, SRV_Channel::SRV_CHANNEL_LIMIT_TRIM);
-    SRV_Channels::set_failsafe_limit(SRV_Channel::k_rudder, SRV_Channel::SRV_CHANNEL_LIMIT_TRIM);
+    SRV_Channels::set_failsafe_limit(SRV_Channel::k_aileron, SRV_Channel::Limit::TRIM);
+    SRV_Channels::set_failsafe_limit(SRV_Channel::k_elevator, SRV_Channel::Limit::TRIM);
+    SRV_Channels::set_failsafe_limit(SRV_Channel::k_throttle, SRV_Channel::Limit::TRIM);
+    SRV_Channels::set_failsafe_limit(SRV_Channel::k_rudder, SRV_Channel::Limit::TRIM);
     
     // setup flight controller to output the min throttle when safety off if arming
     // is setup for min on disarm
     if (arming.arming_required() == AP_Arming::Required::YES_MIN_PWM) {
-        SRV_Channels::set_safety_limit(SRV_Channel::k_throttle, have_reverse_thrust()?SRV_Channel::SRV_CHANNEL_LIMIT_TRIM:SRV_Channel::SRV_CHANNEL_LIMIT_MIN);
+        SRV_Channels::set_safety_limit(SRV_Channel::k_throttle, have_reverse_thrust()?SRV_Channel::Limit::TRIM:SRV_Channel::Limit::MIN);
     }
 }
 
diff --git a/ArduPlane/servos.cpp b/ArduPlane/servos.cpp
index 482753656f..b248ca27d6 100644
--- a/ArduPlane/servos.cpp
+++ b/ArduPlane/servos.cpp
@@ -430,9 +430,9 @@ void Plane::set_servos_controlled(void)
     
     if (!hal.util->get_soft_armed()) {
         if (arming.arming_required() == AP_Arming::Required::YES_ZERO_PWM) {
-            SRV_Channels::set_output_limit(SRV_Channel::k_throttle, SRV_Channel::SRV_CHANNEL_LIMIT_ZERO_PWM);
-            SRV_Channels::set_output_limit(SRV_Channel::k_throttleLeft, SRV_Channel::SRV_CHANNEL_LIMIT_ZERO_PWM);
-            SRV_Channels::set_output_limit(SRV_Channel::k_throttleRight, SRV_Channel::SRV_CHANNEL_LIMIT_ZERO_PWM);
+            SRV_Channels::set_output_limit(SRV_Channel::k_throttle, SRV_Channel::Limit::ZERO_PWM);
+            SRV_Channels::set_output_limit(SRV_Channel::k_throttleLeft, SRV_Channel::Limit::ZERO_PWM);
+            SRV_Channels::set_output_limit(SRV_Channel::k_throttleRight, SRV_Channel::Limit::ZERO_PWM);
         } else {
             SRV_Channels::set_output_scaled(SRV_Channel::k_throttle, 0);
             SRV_Channels::set_output_scaled(SRV_Channel::k_throttleLeft, 0);
@@ -646,8 +646,8 @@ void Plane::servos_twin_engine_mix(void)
     }
     if (!hal.util->get_soft_armed()) {
         if (arming.arming_required() == AP_Arming::Required::YES_ZERO_PWM) {
-            SRV_Channels::set_output_limit(SRV_Channel::k_throttleLeft, SRV_Channel::SRV_CHANNEL_LIMIT_ZERO_PWM);
-            SRV_Channels::set_output_limit(SRV_Channel::k_throttleRight, SRV_Channel::SRV_CHANNEL_LIMIT_ZERO_PWM);
+            SRV_Channels::set_output_limit(SRV_Channel::k_throttleLeft, SRV_Channel::Limit::ZERO_PWM);
+            SRV_Channels::set_output_limit(SRV_Channel::k_throttleRight, SRV_Channel::Limit::ZERO_PWM);
         } else {
             SRV_Channels::set_output_scaled(SRV_Channel::k_throttleLeft, 0);
             SRV_Channels::set_output_scaled(SRV_Channel::k_throttleRight, 0);
@@ -799,9 +799,9 @@ void Plane::set_servos(void)
             SRV_Channels::set_output_scaled(SRV_Channel::k_elevator, 0);
             SRV_Channels::set_output_scaled(SRV_Channel::k_rudder, 0);
         } else if (landing.get_then_servos_neutral() == 2) {
-            SRV_Channels::set_output_limit(SRV_Channel::k_aileron, SRV_Channel::SRV_CHANNEL_LIMIT_ZERO_PWM);
-            SRV_Channels::set_output_limit(SRV_Channel::k_elevator, SRV_Channel::SRV_CHANNEL_LIMIT_ZERO_PWM);
-            SRV_Channels::set_output_limit(SRV_Channel::k_rudder, SRV_Channel::SRV_CHANNEL_LIMIT_ZERO_PWM);
+            SRV_Channels::set_output_limit(SRV_Channel::k_aileron, SRV_Channel::Limit::ZERO_PWM);
+            SRV_Channels::set_output_limit(SRV_Channel::k_elevator, SRV_Channel::Limit::ZERO_PWM);
+            SRV_Channels::set_output_limit(SRV_Channel::k_rudder, SRV_Channel::Limit::ZERO_PWM);
         }
     }