diff --git a/libraries/APM_Control/AP_PitchController.cpp b/libraries/APM_Control/AP_PitchController.cpp
index 15f601a04d..64e5a10478 100644
--- a/libraries/APM_Control/AP_PitchController.cpp
+++ b/libraries/APM_Control/AP_PitchController.cpp
@@ -131,6 +131,13 @@ const AP_Param::GroupInfo AP_PitchController::var_info[] = {
     // @Increment: 0.5
     // @User: Advanced
 
+    // @Param: _RATE_PDMX
+    // @DisplayName: Pitch axis rate controller PD sum maximum
+    // @Description: Pitch axis rate controller PD sum maximum.  The maximum/minimum value that the sum of the P and D term can output
+    // @Range: 0 1
+    // @Increment: 0.01
+    // @User: Advanced
+
     AP_SUBGROUPINFO(rate_pid, "_RATE_", 11, AP_PitchController, AC_PID),
 
     AP_GROUPEND
diff --git a/libraries/APM_Control/AP_RollController.cpp b/libraries/APM_Control/AP_RollController.cpp
index 2faff60caa..f2cb86cf94 100644
--- a/libraries/APM_Control/AP_RollController.cpp
+++ b/libraries/APM_Control/AP_RollController.cpp
@@ -114,6 +114,13 @@ const AP_Param::GroupInfo AP_RollController::var_info[] = {
     // @Increment: 0.5
     // @User: Advanced
 
+    // @Param: _RATE_PDMX
+    // @DisplayName: Roll axis rate controller PD sum maximum
+    // @Description: Roll axis rate controller PD sum maximum.  The maximum/minimum value that the sum of the P and D term can output
+    // @Range: 0 1
+    // @Increment: 0.01
+    // @User: Advanced
+
     AP_SUBGROUPINFO(rate_pid, "_RATE_", 9, AP_RollController, AC_PID),
 
     AP_GROUPEND
diff --git a/libraries/APM_Control/AP_YawController.cpp b/libraries/APM_Control/AP_YawController.cpp
index 31199f5a4f..47b04df4e0 100644
--- a/libraries/APM_Control/AP_YawController.cpp
+++ b/libraries/APM_Control/AP_YawController.cpp
@@ -145,6 +145,13 @@ const AP_Param::GroupInfo AP_YawController::var_info[] = {
     // @Increment: 0.5
     // @User: Advanced
 
+    // @Param: _RATE_PDMX
+    // @DisplayName: Yaw axis rate controller PD sum maximum
+    // @Description: Yaw axis rate controller PD sum maximum.  The maximum/minimum value that the sum of the P and D term can output
+    // @Range: 0 1
+    // @Increment: 0.01
+    // @User: Advanced
+
     AP_SUBGROUPINFO(rate_pid, "_RATE_", 9, AP_YawController, AC_PID),
 
     AP_GROUPEND
diff --git a/libraries/APM_Control/AR_AttitudeControl.cpp b/libraries/APM_Control/AR_AttitudeControl.cpp
index e9f844ba4b..95d23fdc8f 100644
--- a/libraries/APM_Control/AR_AttitudeControl.cpp
+++ b/libraries/APM_Control/AR_AttitudeControl.cpp
@@ -141,6 +141,13 @@ const AP_Param::GroupInfo AR_AttitudeControl::var_info[] = {
     // @Increment: 0.5
     // @User: Advanced
 
+    // @Param: _STR_RAT_PDMX
+    // @DisplayName: Steering control PD sum maximum
+    // @Description: Steering control PD sum maximum.  The maximum/minimum value that the sum of the P and D term can output
+    // @Range: 0.000 1.000
+    // @Increment: 0.01
+    // @User: Advanced
+
     AP_SUBGROUPINFO(_steer_rate_pid, "_STR_RAT_", 1, AR_AttitudeControl, AC_PID),
 
     // @Param: _SPEED_P
@@ -217,6 +224,13 @@ const AP_Param::GroupInfo AR_AttitudeControl::var_info[] = {
     // @Increment: 0.5
     // @User: Advanced
 
+    // @Param: _SPEED_PDMX
+    // @DisplayName: Speed control PD sum maximum
+    // @Description: Speed control PD sum maximum.  The maximum/minimum value that the sum of the P and D term can output
+    // @Range: 0.000 1.000
+    // @Increment: 0.01
+    // @User: Advanced
+
     AP_SUBGROUPINFO(_throttle_speed_pid, "_SPEED_", 2, AR_AttitudeControl, AC_PID),
 
     // @Param: _ACCEL_MAX
@@ -353,6 +367,13 @@ const AP_Param::GroupInfo AR_AttitudeControl::var_info[] = {
     // @Increment: 0.5
     // @User: Advanced
 
+    // @Param: _BAL_PDMX
+    // @DisplayName: Pitch control PD sum maximum
+    // @Description: Pitch control PD sum maximum.  The maximum/minimum value that the sum of the P and D term can output
+    // @Range: 0.000 1.000
+    // @Increment: 0.01
+    // @User: Advanced
+
     AP_SUBGROUPINFO(_pitch_to_throttle_pid, "_BAL_", 10, AR_AttitudeControl, AC_PID),
 
     // @Param: _BAL_PIT_FF
@@ -437,6 +458,13 @@ const AP_Param::GroupInfo AR_AttitudeControl::var_info[] = {
     // @Increment: 0.5
     // @User: Advanced
 
+    // @Param: _SAIL_PDMX
+    // @DisplayName: Sail Heel control PD sum maximum
+    // @Description: Sail Heel control PD sum maximum.  The maximum/minimum value that the sum of the P and D term can output
+    // @Range: 0.000 1.000
+    // @Increment: 0.01
+    // @User: Advanced
+
     AP_SUBGROUPINFO(_sailboat_heel_pid, "_SAIL_", 12, AR_AttitudeControl, AC_PID),
 
     // @Param: _TURN_MAX_G