#include <ModbusSerial.h>

// Define pins
#define PIN_INPUT 3
#define PIN_LED 13

// Create Modbus object
ModbusSerial mb(Serial, 1); // Assuming slave ID is 1

void setup() {
  Serial.begin(9600);
  pinMode(PIN_INPUT, INPUT);
  pinMode(PIN_LED, OUTPUT);
}

void loop() {
  int sensorVal = digitalRead(PIN_INPUT);
  mb.task(); // Update Modbus communication
  delay(500);
}