ReadHolding register by Arduino uno

Projects Programming
8 
#include <ModbusMaster.h>
#include <SoftwareSerial.h>
//#include <AltSoftSerial.h>
// Construct software serial object for Modbus/PC
#if defined(ARDUINO_AVR_UNO)
const int SSRxPin = 10; // Recieve pin for software serial 
const int SSTxPin = 11; // Send pin for software serial 
SoftwareSerial SoftSerial(SSRxPin, SSTxPin);
#else
// This is just a assigning another name to the same port, for convienence
// Unless it is unavailable, always prefer hardware serial.
HardwareSerial* SoftSerial = &Serial1;
#endif

#define MAX485_DE      3
#define MAX485_RE_NEG  2

// instantiate ModbusMaster object
ModbusMaster node;

void preTransmission()
{
  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);
  // Init in receive mode
  digitalWrite(MAX485_RE_NEG, 0);
  digitalWrite(MAX485_DE, 0);

  // Turn On Main/Hardware Serial Port
  Serial.begin(9600);
  
    // Turn on Soft serial port
#if defined (ARDUINO_AVR_UNO)
    SoftSerial.begin(9600);
    // NOTE:  Software serial only supports 8N1
#else
    Serial1.begin(9600, SERIAL_8E1);
#endif
   
  // Start the Modbus instance with Modbus slave ID 10 and Hardware Serial port
  node.begin(10, SoftSerial);
  
  // Callbacks allow us to configure the RS485 transceiver correctly
  node.preTransmission(preTransmission);
  node.postTransmission(postTransmission);
}

void loop()
{
  uint8_t result;
  uint16_t data[6];
  
  // Read 02 registers starting at 40033)

   result = node.readHoldingRegisters(33,2);
  if (result == node.ku8MBSuccess)
  {
    Serial.println("Success");
    Serial.println(node.getResponseBuffer(0x00));
    Serial.println(node.getResponseBuffer(0x01));
                 
  }
  else
  {
    Serial.println(" Failed ");
}
delay(1000);
}