[PIC] DAC output destroyed (PIC16F1783)

//================================================================
// Spectrograph temperature regulation (PI feedback controller)
// File:   newfile.c
// Author: Tobias Feger
//
// Created on 3. May 2014
//===============================================================

//****************************** include/pragma and define:
#include <xc.h>
#include <pic.h>
#include <plib/adc.h>
#include <plib/delays.h>
#include <stdlib.h>
#include <htc.h>
#include <stdio.h>
#include <math.h>

#pragma config LVP = OFF
#pragma config MCLRE = OFF         // MCLR Pin Function Select (MCLR/VPP pin function is MCLR)
#pragma config FOSC = INTOSC    // (ECH, External Clock, High Power Mode (4-32 MHz); device clock supplied to CLKIN pin)
#pragma config WDTE = OFF       // Watchdog Timer Enable (WDT enabled)
#pragma config PWRTE = ON       // Power-up Timer Enable (PWRT disabled), Sprut: ON!
#pragma config CP = OFF         // Flash Program Memory Code Protection (Program memory code protection is disabled)
#pragma config BOREN = OFF      // Brown-out Reset Enable (Brown-out Reset enabled)

#define _XTAL_FREQ 32000000

//****************************** Variables:
unsigned int  adc_AN0 = 0;   // channel 1
unsigned int  adc_AN1 = 0;   // channel 2
unsigned int  adc_AN4 = 0;   // channel 4
unsigned int  adc_AN5 = 0;   // channel 5

double AN0_voltage;
double AN1_voltage;

float Setpoint=24.2;        //Setpoint temperature
float Error=0.0;
float Integral=0.0;
float kP=5.0;                //P-gain
float kI=0.1;                //I-gain

float R0=10.0;         //Thermistor 10K at 25deg
float T0=298.0;
float Test=0.0;
double diff_voltage; 
float dR;
float R2;
float sleep_1=0.0;
float sleep_2=0.0;

double T1;
double T_bridge;

int myint1;
int myint2;
//****************************** Delay function (brauchmer net):
void delay(int ms)
{
    while(ms-- > 0){__delay_ms(1);}
}

//********** Initialize the DAC converter:
// read: http://electronics.stackexchange.com/questions/107756/pic12-dac-has-no-output
// DACOUT1 = RA2, DACREF = RA3 (5V)
void init_dac(void)
{
    ANSELA=0b00000000;     //all pins to digital
    PORTA=0x00;   
    DACCON0=0b10100000;    //Make RA2 as output!  
}

//********** Initialize the ADC converter:
// ADCREF = RA3 (5V)
void init_adc(void)
{
    PORTA=0x00;     
    TRISA=0b11111111;     //Port A is all inputs.   
    ANSELA=0b00000011;     //Pin RA0 and RA1 are analog inputs
    ANSELA=0;
    ADCON0=0b00000001;     //all inputs are digital except of AN0 
    ADCON1=0b10010000; 
    ADCON2=0b00001111; 
}

//********** Preform the AD conversion:
unsigned int GetADCvalue(int channel)
{
    if(channel==0){ADCON0=0b00000001;}
    if(channel==1){ADCON0=0b00000101;}
    if(channel==3){ADCON0=0b00001101;}
    //if(channel==4){ADCON0=0b00010001;}

    GO_nDONE = 1;                      //start the ADC conversion
    __delay_ms(5);
    while(GO_nDONE);                 //wait for the conversion to finish
    return ((ADRESH<<8)+ADRESL);    //return the result
}

//********** Heater control:
float GetDrive(float Test)
{
    sleep_1=500.0*Test;    
    sleep_2=500.0*(1.0-Test);
    myint1=sleep_1;
    myint2=sleep_2;
       
    if(Test==0.0){DACCON1=0;}
    else{DACCON1=255;} 
    delay(myint1);    
 
     if(Test==1.0){DACCON1=255;}    
    else{DACCON1=0;}
    delay(myint2);        
}

//=======================================================================================
void main(void){
    PORTB=0x00;
    TRISB=0x00;  
    OSCCON=0b11111000; //Setup internal oscillator 32MHz
    init_adc();    //initialise ADC
    init_dac();    //initialise DAC
 
    while(1)
        {
        adc_AN0=GetADCvalue(0);                 // ADC channel 1
        AN0_voltage=(adc_AN0)/4096.0*5.0;
        adc_AN1=GetADCvalue(1);                 // ADC channel 2
        AN1_voltage=(adc_AN1)/4096.0*5.0;

        
        diff_voltage=AN1_voltage-AN0_voltage;
        dR=2.0*R0*diff_voltage/(5.0-diff_voltage);
        R2=R0+dR;
        
        T_bridge=1.0/T0+log(R2/R0)/3920.0;           
        T1=(1.0/T_bridge)-273.0;

        Error=T1-Setpoint;
        Integral=Integral+Error;
        if(Integral>0.5/kI){Integral=0.5/kI;}             //+5 upper boundary
        else if(Integral<-0.5/kI){Integral=-0.5/kI;}    //-5 lower boundary
            
        Test=0.5-(Error*kP)-(Integral*kI);
           if(Test<0.0){Test=0.0;}
        if(Test>1.0){Test=1.0;} 
        GetDrive(Test);
        }//end while(1)

}//end main