namespace NModbus.TestDriver
    using System;
    using System.Net.Sockets;
    using Modbus.Device;
    using NModbus;
    class Program
        static void Main(string[] args)
                         using (TcpClient client = new TcpClient("192.168.111.169", 502))
                    client.Client.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.KeepAlive, true);
                    var master = ModbusIpMaster.CreateIp(client);
                    // read five input values
                  byte slaveId = 1;
                ushort startAddress = 1;
                ushort numRegisters = 5;
                // read five registers      
                ushort[] registers = master.ReadHoldingRegisters(slaveId, startAddress, numRegisters);
                for (int i = 0; i < numRegisters; i++)
                    Console.WriteLine($"Register {startAddress + i}={registers[i]}");