diff --git a/Config.cpp b/Config.cpp
new file mode 100644
index 0000000..13e7ae4
--- /dev/null
+++ b/Config.cpp
@@ -0,0 +1,54 @@
+#include "Config.h"
+
+
+float Config::getFloat(int pos) {
+  u_float u;
+  for (uint8_t i = 0; i < sizeof(float); i++) {
+    u.e[i] = EEPROM.read(pos + i);
+  }
+  return u.f;
+}
+
+void Config::setFloat(int pos, float value) {
+  u_float u;
+  u.f = value;
+  for (uint8_t i = 0; i < sizeof(float); i++) {
+    EEPROM.write(pos + i, u.e[i]);
+  }
+}
+
+unsigned int Config::getUInt32(int pos) {
+  u_uint32 u;
+  for (uint8_t i = 0; i < sizeof(uint32_t); i++) {
+    u.e[i] = EEPROM.read(pos + i);
+  }
+  return u.i;
+}
+
+void Config::setUInt32(int pos, uint32_t value) {
+  u_uint32 u;
+  u.i = value;
+  for (uint8_t i = 0; i < sizeof(uint32_t); i++) {
+    EEPROM.write(pos + i, u.e[i]);
+  }
+}
+
+bool Config::isInitialized() {
+  uint32_t magic = getUInt32(MAGIC);
+  return magic == MAGIC_TOKEN;
+}
+
+void Config::setMagic() {
+  setUInt32(MAGIC, MAGIC_TOKEN);
+}
+
+void Config::initialize() {
+  if (! isInitialized()) {
+    setFloat(ADC1START, 0.0);
+    setFloat(ADC1START + 4, 1.0);
+    setFloat(ADC2START, 0.0);
+    setFloat(ADC2START + 4, 1.0);
+
+    setMagic();
+  }
+}
diff --git a/Config.h b/Config.h
new file mode 100644
index 0000000..b0f4674
--- /dev/null
+++ b/Config.h
@@ -0,0 +1,36 @@
+#ifndef _config_h_
+#define _config_h_
+
+#include <stdint.h>
+
+
+typedef union {
+  float f;
+  uint8_t e[sizeof(float)];
+} u_float;
+
+typedef union {
+  uint32_t i;
+  uint8_t e[sizeof(uint32_t)];
+} u_uint32;
+
+
+namespace Config {
+	const uint32_t MAGIC_TOKEN = 0xDEADBEEF;
+    
+	const int MAGIC = 0;
+	const int ADC1START = 4;
+	const int ADC2START = 12;
+	
+	void initialize();
+  	bool isInitialized();
+  	float getFloat(int pos);
+  	void setFloat(int pos, float value);
+  	uint32_t getUInt32(int pos);
+  	void setUInt32(int pos, uint32_t value);
+
+  	void setMagic();
+}
+
+
+#endif // _config_h_
\ No newline at end of file
diff --git a/ModbusThermometer.cpp b/ModbusThermometer.cpp
index 6e7a1c4..bf0982a 100644
--- a/ModbusThermometer.cpp
+++ b/ModbusThermometer.cpp
@@ -5,6 +5,7 @@
 #include "ads1210.h"
 #include "led.h"
 #include "SimpleModbusSlave.h"
+#include "Config.h"
 
 const uint8_t LED_PIN = 8;
 
@@ -61,6 +62,7 @@ struct {
 
 void setup() {  
   delay(100);
+  Config::initialize();
   led.begin(LED_PIN);
   ads1210_1.begin(ADC_1_CS_PIN, ADC_1_RDY_PIN);
   ads1210_2.begin(ADC_2_CS_PIN, ADC_2_RDY_PIN);
diff --git a/ads1210.cpp b/ads1210.cpp
index 72e5c4c..233c7b2 100644
--- a/ads1210.cpp
+++ b/ads1210.cpp
@@ -77,11 +77,8 @@ void ADS1210::exec() {
 		value = res.out;
 		
 		u = (((float)value) / ((float)V_MAX)) * U_REF;
-		r = ((((float)V_MAX) / ((float)value)) - 1.0) * R_REF;
-
-		if (value == 0) {
-			// fatal(2);
-		}
+		rRaw = ((((float)V_MAX) / ((float)value)) - 1.0) * R_REF;
+		r = (rRaw + m_calOffset) * m_calFactor;
 	}
 }
 
@@ -133,6 +130,9 @@ void ADS1210::begin(uint8_t csPin, uint8_t drdyPin) {
 	setMode(CMR_MD_SelfCalibration);
 	waitForDRdy();
 	// Serial << "done." << endl;
+	
+	m_calOffset = 0.0;
+	m_calFactor = 1.0;
 }
 
 
diff --git a/ads1210.h b/ads1210.h
index 5fa40b6..8e3bcde 100644
--- a/ads1210.h
+++ b/ads1210.h
@@ -11,11 +11,12 @@
 class ADS1210 {
 public:
 	ADS1210() : value(0) {};
-	void begin(uint8_t csPin, uint8_t drdyPin);
+	void begin(uint8_t csPin, uint8_t drdyPin, int eepromAddr);
 	void exec();
 
     uint32_t value;
 	float u;
+	float rRaw;
 	float r;
 private:
 	// register addresses
@@ -77,6 +78,9 @@ private:
 
 	uint8_t m_csPin;
 	uint8_t m_drdyPin;
+	int m_eepromAddr;
+	float m_calFactor;
+	float m_calOffset;
 	
 
 	void enableCS() const;