diff --git a/libraries/AP_ADC/AP_ADC.h b/libraries/AP_ADC/AP_ADC.h
index de3ed07252..8bebead3fc 100644
--- a/libraries/AP_ADC/AP_ADC.h
+++ b/libraries/AP_ADC/AP_ADC.h
@@ -27,7 +27,7 @@ class AP_ADC
 	virtual void Init(AP_PeriodicProcess * scheduler = NULL) = 0;
 
 	/* read one channel value */
-	virtual uint16_t Ch(uint8_t ch_num) = 0;
+	virtual float Ch(uint8_t ch_num) = 0;
 
 	/* read 6 channels values as a set, used by IMU for 3 gyros
 	   and 3 accelerometeres.
diff --git a/libraries/AP_ADC/AP_ADC_ADS7844.cpp b/libraries/AP_ADC/AP_ADC_ADS7844.cpp
index b319b29f7d..4a415822e9 100644
--- a/libraries/AP_ADC/AP_ADC_ADS7844.cpp
+++ b/libraries/AP_ADC/AP_ADC_ADS7844.cpp
@@ -162,7 +162,7 @@ void AP_ADC_ADS7844::Init( AP_PeriodicProcess * scheduler )
 }
 
 // Read one channel value
-uint16_t AP_ADC_ADS7844::Ch(uint8_t ch_num)
+float AP_ADC_ADS7844::Ch(uint8_t ch_num)
 {
 	uint16_t count;
 	uint32_t sum;
@@ -178,7 +178,7 @@ uint16_t AP_ADC_ADS7844::Ch(uint8_t ch_num)
 	_sum[ch_num]   = 0;
 	sei();
 
-	return sum/count;
+	return ((float)sum)/count;
 }
 
 // Read 6 channel values
diff --git a/libraries/AP_ADC/AP_ADC_ADS7844.h b/libraries/AP_ADC/AP_ADC_ADS7844.h
index 325bc62b51..f0a83fcf8e 100644
--- a/libraries/AP_ADC/AP_ADC_ADS7844.h
+++ b/libraries/AP_ADC/AP_ADC_ADS7844.h
@@ -24,7 +24,7 @@ class AP_ADC_ADS7844 : public AP_ADC
 	void Init( AP_PeriodicProcess * scheduler );
 
 	// Read 1 sensor value
-	uint16_t Ch(unsigned char ch_num);
+	float Ch(unsigned char ch_num);
 
 	// Read 6 sensors at once
 	uint32_t Ch6(const uint8_t *channel_numbers, uint16_t *result);
diff --git a/libraries/AP_ADC/AP_ADC_HIL.cpp b/libraries/AP_ADC/AP_ADC_HIL.cpp
index 9b0602bd4c..5a0cb92583 100644
--- a/libraries/AP_ADC/AP_ADC_HIL.cpp
+++ b/libraries/AP_ADC/AP_ADC_HIL.cpp
@@ -44,7 +44,7 @@ void AP_ADC_HIL::Init( AP_PeriodicProcess * scheduler )
 }
 
 // Read one channel value
-uint16_t AP_ADC_HIL::Ch(unsigned char ch_num)
+float AP_ADC_HIL::Ch(unsigned char ch_num)
 {
 	return adcValue[ch_num];
 }
diff --git a/libraries/AP_ADC/AP_ADC_HIL.h b/libraries/AP_ADC/AP_ADC_HIL.h
index 07c7181aaa..dee48c586c 100644
--- a/libraries/AP_ADC/AP_ADC_HIL.h
+++ b/libraries/AP_ADC/AP_ADC_HIL.h
@@ -32,7 +32,7 @@ class AP_ADC_HIL : public AP_ADC
 
 	///
 	// Read the sensor, part of public AP_ADC interface
-	uint16_t Ch(unsigned char ch_num);
+	float Ch(unsigned char ch_num);
 
 	///
 	// Read 6 sensors at once