/*
readCoils(slave_address, address, quantity);
readDiscreteInputs(slave_address, address, quantity);
readHoldingRegisters(slave_address, address, quantity);
readInputRegisters(slave_address, address, quantity);
writeSingleCoil(slave_address, address, value);
writeSingleRegister(slave_address, address, value);
writeMultipleCoils(slave_address, address, values, quantity);
writeMultipleRegisters(slave_address, address, values, quantity);
 */

#include <ModbusMaster.h>               //Library for using ModbusMaster
#include   <dht.h>

#define   DHT22_PIN 2 // Adjust based on your DHT sensor model (4 or 5)

//int ran;
#define MAX485_DE      3

#define MAX485_RE_NEG  4

dht DHT;
float hum;  // Stores humidity value
float temp; // Stores temperature value


ModbusMaster node;                    //object node for class ModbusMaster  8bits,none parity,1 stop bit
void preTransmission()            //Function for setting stste of Pins DE & RE of RS-485

{
  digitalWrite(MAX485_RE_NEG, 1);             
  digitalWrite(MAX485_DE, 1);
}
void postTransmission()
{
  digitalWrite(MAX485_RE_NEG, 0);
  digitalWrite(MAX485_DE, 0);
}
void setup()
{
  pinMode(MAX485_RE_NEG, OUTPUT);
  pinMode(MAX485_DE, OUTPUT);
  pinMode(LED_BUILTIN, OUTPUT);
  digitalWrite(MAX485_RE_NEG, 0);
  digitalWrite(MAX485_DE, 0);
  Serial.begin(9600);             //Baud Rate as 9600

  node.begin(1, Serial);            //Slave ID as 1
  node.preTransmission(preTransmission);         //Callback for configuring RS-485 Transreceiver correctly
  node.postTransmission(postTransmission);

}
void loop()
{

delay(2000); // Adjust delay as needed
 int chk = DHT.read22(DHT22_PIN);
  int result;
 

   hum = DHT.humidity;
   temp= DHT.temperature;


 // ran=random(0,10);
  uint16_t value = temp * 10;

  node.clearResponseBuffer();
  node.clearTransmitBuffer();
  result = node.writeSingleRegister(40001,value); 
  if (result != node.ku8MBSuccess) {
    Serial.print("Failed to write temperature to Modbus register! Error: ");
    Serial.println(result, HEX);
  }     
 /* 
// Read temperature and humidity values from Modbus registers
  node.clearResponseBuffer();
  node.clearTransmitBuffer();
  result = node.readInputRegisters(0x0001, 1);
  if (result == node.ku8MBSuccess) {
    temp = node.getResponseBuffer(0) / 10.0;  // Divide by 10 to get the actual temperature
    Serial.print("Read temperature from Modbus: ");
    Serial.print(temp);
    Serial.println(" °C");
  } else {
    Serial.print("Failed to read temperature from Modbus! Error: ");
    Serial.println(result, HEX);
  }
*/

delay(4000); 

 /*int led = node.readHoldingRegisters(0x40006,1);
  if(led==1)
  {
    digitalWrite(LED_BUILTIN, LOW);
  }
  else if(led==0)
  {
    digitalWrite(LED_BUILTIN, HIGH);
  }*/
}