arduino modbus ESP32 Server

Here is an example code for creating a Modbus TCP server using an ESP32 and Arduino IDE:

#include <WiFi.h>
#include <ModbusTCPSlave.h>

// WiFi credentials
const char* ssid = "your_SSID";
const char* password = "your_PASSWORD";

// Modbus TCP server settings
const IPAddress ip(192, 168, 1, 100);
const uint16_t port = 502;
const uint16_t coilsCount = 8;
uint8_t coils[coilsCount];

// Modbus TCP server object
ModbusTCPSlave modbusServer;

void setup() {
  Serial.begin(115200);
  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED) {
    delay(1000);
    Serial.println("Connecting to WiFi...");
  }
  Serial.println("WiFi connected!");

  // Set the IP address and port of the Modbus TCP server
  modbusServer.configServer(ip, port);

  // Initialize coils
  for (uint16_t i = 0; i < coilsCount; i++) {
    coils[i] = 0;
  }

  // Add coils to the Modbus TCP server
  modbusServer.addCoils(0, coilsCount, coils);

  Serial.println("Modbus TCP server started.");
}

void loop() {
  // Handle Modbus TCP requests
  modbusServer.task();
}

In this code, the ESP32 is connected to a WiFi network using the `WiFi.h` library. The Modbus TCP server is created using the `ModbusTCPSlave.h` library. The IP address and port of the server are set using the `configServer()` method. Coils are initialized and added to the server using the `addCoils()` method. Finally, the `task()` method is called in the `loop()` function to handle Modbus TCP requests.

You can modify this code to add other types of Modbus data, such as holding registers or input registers, by using the appropriate methods provided by the `ModbusTCPSlave` class.