Loaded Libraries:
NewLiquidCrystal
// or LiquidCrystal
Wire

/*
Configuration bytes:
// 12-bit device values from 0-4095
// page 18-19 spec sheet
buffer[0] = 0b01000000; // control byte
// bits 7-5; 010 write DAC; 011 write DAC and EEPROM
// bits 4-3 unused
// bit 0 unused
buffer[1] = 0b00000000; //HIGH data
// bits 7-0 D11-D4
buffer[2] = 0b00000000; // LOW data
// bits 7-4 D3-D0
// bits 3-0 unused
*/

#include <Wire.h> // specify use of Wire.h library
#define MCP4725 0x60 // MCP4725 base address
byte buffer[3];
unsigned int val;
#include <FastIO.h>
#include <I2CIO.h>
#include <LCD.h>
#include <LiquidCrystal_I2C.h>
LiquidCrystal_I2C lcd(0x27, 2, 1, 0, 4, 5, 6, 7, 3, POSITIVE); // Setup LCD
//LiquidCrystal_I2C lcd(0x27,16,2) LCD address may be different as to a LCD vendor specification

void setup() {
	pinMode(4, INPUT); // pin to starts measurement
	pinMode(13, OUTPUT); // Relay swith ON to start compromising
	pinMode(A0, INPUT); // pin as Analog IN to measure zone loop voltage
} // end setup

void loop() {
	int u = 0;
	int val = 0;
	buffer[0] = 0b01000000; // control byte
	delay(200); //Wait
	u = analogRead(0);
	val = u * 4; // read pot
	buffer[1] = val >> 4; // MSB 11-4 shift right 4 places
	buffer[2] = val << 4; // LSB 3-0 shift left 4 places
	float sensorValue = 0;
	sensorValue = u  *(5.0/1023.0) * 4;
	Wire.begin(); // begin I2C
	lcd.begin(16,2);
	lcd.backlight();
	lcd.setCursor(0, 0);
	lcd.print("Measured Volts =");
	lcd.setCursor(0, 1);
	lcd.print(sensorValue);
	lcd.print("__");
	lcd.print(u);
	delay(500);

	while (digitalRead(4) == LOW) {
		//digitalWrite(2, HIGH); // ready LED ON, option
		delay(200); // delay for conats to sabilize
		Wire.beginTransmission(MCP4725); // address device
		Wire.write(buffer[0]); // pointer
		Wire.write(buffer[1]); // 8 MSB
 		Wire.write(buffer[2]); // 4 LSB
 		Wire.endTransmission();
 		delay(200); //Wait
 		digitalWrite(13, HIGH); //Relay 2 ON to compromise burglary zoneloop
 		delay(20000); //Wait
 	}
} // end loop