diff --git a/uc/Makefile b/uc/Makefile
index 639daa8..38a527a 100755
--- a/uc/Makefile
+++ b/uc/Makefile
@@ -44,11 +44,12 @@ TARGET = main
 #
 # Predefine the TYPE and SENSORx C macros in main.h via this Makefile.
 # Override the defaults on the command line by typing:
-# make TYPE=xxxx SENSOR0=yyyy ...
+# make PHASE=x METERCONST=y SENSOR0=z ...
 #
 DBG = 0
 #
 TYPE = 2300501
+PHASE = 1
 METERCONST= 5508
 #
 SENSOR0 = 0123456789abcdef0123456789abcde0
@@ -56,7 +57,7 @@ SENSOR1 = 0123456789abcdef0123456789abcde1
 SENSOR2 = 0123456789abcdef0123456789abcde2
 SENSOR3 = 0123456789abcdef0123456789abcde3
 #
-CEXTRA = -D DBG=$(DBG) -D METERCONST=$(METERCONST) -D 'SENSOR0="$(SENSOR0)"' -D 'SENSOR1="$(SENSOR1)"' -D 'SENSOR2="$(SENSOR2)"' -D 'SENSOR3="$(SENSOR3)"'
+CEXTRA = -D DBG=$(DBG) -D PHASE=$(PHASE) -D METERCONST=$(METERCONST) -D 'SENSOR0="$(SENSOR0)"' -D 'SENSOR1="$(SENSOR1)"' -D 'SENSOR2="$(SENSOR2)"' -D 'SENSOR3="$(SENSOR3)"'
 ###############################################################################
 
 
diff --git a/uc/main.c b/uc/main.c
index 7ebbd6e..8114edb 100644
--- a/uc/main.c
+++ b/uc/main.c
@@ -79,8 +79,11 @@ ISR(TIMER2_COMPA_vect) {
 #endif
   // read ADC result
   // add to nano(Wh) counter
+#if PHASE == 2
+  MacU16X16to32(aux[0].nano, METERCONST, ADC);
+#else
   MacU16X16to32(aux[muxn].nano, METERCONST, ADC);
-
+#endif
   if (aux[muxn].nano > WATT) {
      measurements[muxn].value++;
      aux[muxn].pulse = true;
diff --git a/uc/main.h b/uc/main.h
index 7eede99..1596d88 100644
--- a/uc/main.h
+++ b/uc/main.h
@@ -42,6 +42,10 @@
   #error "SENSOR3 not defined"
 #endif
 
+#ifndef PHASE
+  #error "PHASE not defined"
+#endif
+
 #ifndef METERCONST
   #error "METERCONST not defined"
 #endif