Nano_Modbus_Address_Scanner

#include <SoftwareSerial.h>
#include <ModbusMaster.h>

// SoftwareSerial pins for RS485 communication
#define RX_PIN 2
#define TX_PIN 3

// Modbus settings
#define BAUD_RATE 4800
#define START_ADDRESS 0x0000
#define READ_COUNT 2  // Number of registers to read

SoftwareSerial modbusSerial(RX_PIN, TX_PIN);  // RX, TX
ModbusMaster node;

void setup() {
  Serial.begin(9600);  // Arduino Serial Monitor
  delay(1000);

  Serial.println();
  Serial.println("Arduino Nano Modbus Address Scanner");
  Serial.println("--------------------------------");

  // Initialize SoftwareSerial for RS485
  modbusSerial.begin(BAUD_RATE);

  // Initialize ModbusMaster node and link serial stream
  node.begin(1, modbusSerial);

  delay(500);
}

void loop() {
  // Adjust range as needed (1 to 247 for full scan)
  for (uint8_t slaveID = 1; slaveID <= 10; slaveID++) {
    node.begin(slaveID, modbusSerial);

    uint8_t result = node.readHoldingRegisters(START_ADDRESS, READ_COUNT);
    //uint8_t result = node.readInputRegisters(START_ADDRESS, READ_COUNT);

    if (result == node.ku8MBSuccess) {
      Serial.print("FOUND device at Modbus ID: ");
      Serial.println(slaveID);

      Serial.print("  Registers: ");
      for (uint8_t i = 0; i < READ_COUNT; i++) {
        Serial.print(node.getResponseBuffer(i));
        Serial.print(" ");
      }
      Serial.println();
    } else {
      Serial.print("Failed ID ");
      Serial.print(slaveID);
      Serial.print(" - Error: 0x");
      Serial.println(result, HEX);
    }

    delay(50);  // Avoid bus congestion
  }

  Serial.println("--------------------------------");
  Serial.println("Scan complete. Restarting in 3 seconds...");
  Serial.println();
  delay(3000);
}