diff --git a/libraries/AC_PID/AC_P.h b/libraries/AC_PID/AC_P.h
index be310b7380..d07245793d 100644
--- a/libraries/AC_PID/AC_P.h
+++ b/libraries/AC_PID/AC_P.h
@@ -24,7 +24,7 @@ public:
     /// @param  initial_p       Initial value for the P term.
     ///
     AC_P(
-        const float &   initial_p = 0.0)
+        const float &   initial_p = 0.0f)
     {
 		AP_Param::setup_object_defaults(this, var_info);
         _kp = initial_p;
diff --git a/libraries/AC_PID/examples/AC_PID_test/AC_PID_test.pde b/libraries/AC_PID/examples/AC_PID_test/AC_PID_test.pde
index f4e723486d..a3490d37d7 100644
--- a/libraries/AC_PID/examples/AC_PID_test/AC_PID_test.pde
+++ b/libraries/AC_PID/examples/AC_PID_test/AC_PID_test.pde
@@ -40,12 +40,12 @@
 const AP_HAL::HAL& hal = AP_HAL_BOARD_DRIVER;
 
 // default PID values
-#define TEST_P 1.0
-#define TEST_I 0.01
-#define TEST_D 0.2
+#define TEST_P 1.0f
+#define TEST_I 0.01f
+#define TEST_D 0.2f
 #define TEST_IMAX 10
-#define TEST_FILTER 5.0
-#define TEST_DT 0.01
+#define TEST_FILTER 5.0f
+#define TEST_DT 0.01f
 
 // setup function
 void setup()