OnlineMonitorSystem/NModbus/Modbus.cs

namespace NModbus
{
    /// <summary>
    ///     Defines constants related to the Modbus protocol.
    /// </summary>
    internal static class Modbus
    {
        public const int MaximumDiscreteRequestResponseSize = 2040;
        public const int MaximumRegisterRequestResponseSize = 127;

        // modbus slave exception offset that is added to the function code, to flag an exception
        public const byte ExceptionOffset = 128;

        // default setting for number of retries for IO operations
        public const int DefaultRetries = 3;

        // default number of milliseconds to wait after encountering an ACKNOWLEGE or SLAVE DEVIC BUSY slave exception response.
        public const int DefaultWaitToRetryMilliseconds = 250;

        // default setting for IO timeouts in milliseconds
        //public const int DefaultTimeout = 1000;

      
        public const ushort CoilOn = 0xFF00;
        public const ushort CoilOff = 0x0000;

        // IP slaves should be addressed by IP
        public const byte DefaultIpSlaveUnitId = 0;

        //// An existing connection was forcibly closed by the remote host
        //public const int ConnectionResetByPeer = 10054;

        // Existing socket connection is being closed
        //public const int WSACancelBlockingCall = 10004;

        // used by the ASCII tranport to indicate end of message
        public const string NewLine = "\r\n";
    }
}