diff --git a/src/Makefile b/src/Makefile
index 79fbec1e5..575aa7361 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -63,9 +63,13 @@ HAPTIC = NO
 # SPLASH on START
 SPLASH = YES
 
+# PPM center adjustable
+# Values = YES, NO
+PPM_CENTER_ADJUSTABLE = YES
+
 # Limits display in the LIMITS
 # Values = PERCENT, US
-LIMITS = PERCENT
+PPM_LIMITS_UNIT = PERCENT
 
 # Decimals display in the main view / PPM calibration, 
 # Values = YES, NO
@@ -352,8 +356,12 @@ endif
 
 ### Global Build-Option Directives ###
 
-ifeq ($(LIMITS), US)
-  CPPDEFS += -DLIMITS_US
+ifeq ($(PPM_CENTER_ADJUSTABLE), YES)
+  CPPDEFS += -DPPM_CENTER_ADJUSTABLE
+endif
+
+ifeq ($(PPM_LIMITS_UNIT), US)
+  CPPDEFS += -DPPM_LIMITS_UNIT_US
 endif
 
 ifeq ($(DECIMALS), YES)
diff --git a/src/model_menus.cpp b/src/model_menus.cpp
index 8a54d6969..834a45199 100644
--- a/src/model_menus.cpp
+++ b/src/model_menus.cpp
@@ -1717,7 +1717,7 @@ void menuProcLimits(uint8_t event)
       switch(j)
       {
         case 0:
-#ifdef LIMITS_US
+#ifdef PPM_LIMITS_UNIT_US
           lcd_outdezAtt(  8*FW, y,  ((ld->offset)*128) / 25, attr|PREC1);
 #else
           lcd_outdezAtt(  8*FW, y,  ld->offset, attr|PREC1);
@@ -1733,7 +1733,7 @@ void menuProcLimits(uint8_t event)
           }
           break;
         case 1:
-#ifdef LIMITS_US
+#ifdef PPM_LIMITS_UNIT_US
           lcd_outdezAtt(12*FW+1, y, (((int16_t)ld->min-100)*128) / 25, attr | INFLIGHT(ld->min));
 #else
           lcd_outdezAtt(12*FW, y, (int8_t)(ld->min-100), attr | INFLIGHT(ld->min));
@@ -1743,7 +1743,7 @@ void menuProcLimits(uint8_t event)
           }
           break;
         case 2:
-#ifdef LIMITS_US
+#ifdef PPM_LIMITS_UNIT_US
           lcd_outdezAtt(16*FW, y, (((int16_t)ld->max+100)*128) / 25, attr | INFLIGHT(ld->max));
 #else
           lcd_outdezAtt(17*FW, y, (int8_t)(ld->max+100), attr | INFLIGHT(ld->max));
diff --git a/src/pulses_avr.cpp b/src/pulses_avr.cpp
index 44a0047b0..231a90b47 100644
--- a/src/pulses_avr.cpp
+++ b/src/pulses_avr.cpp
@@ -210,7 +210,7 @@ FORCEINLINE void setupPulsesPPM()
     uint16_t rest = 22500u*2-q; //Minimum Framelen=22.5 ms
     rest += (int16_t(g_model.ppmFrameLength))*1000;
     for (uint8_t i=0; i<p; i++) {
-#ifdef LIMITS_US
+#ifdef PPM_LIMITS_UNIT_US
       int16_t v = limit((int16_t)-PPM_range, g_chans512[i], (int16_t)PPM_range) + 2*(PPM_CENTER+g_model.servoCenter[i]);
 #else
       int16_t v = limit((int16_t)-PPM_range, g_chans512[i], (int16_t)PPM_range) + 2*PPM_CENTER;
@@ -821,7 +821,7 @@ void setupPulsesPPM16()
     uint16_t rest=22500u*2-q; //Minimum Framelen=22.5 ms
     rest += (int16_t(g_model.ppmFrameLength))*1000;
     for (uint8_t i=p-8; i<p; i++) { //NUM_CHNOUT
-#ifdef LIMITS_US
+#ifdef PPM_LIMITS_UNIT_US
       int16_t v = limit((int16_t)-PPM_range, g_chans512[i], (int16_t)PPM_range) + 2*(PPM_CENTER+g_model.servoCenter[i]);
 #else
       int16_t v = limit((int16_t)-PPM_range, g_chans512[i], (int16_t)PPM_range) + 2*PPM_CENTER;