initial version

Modbus.cs

@@ -0,0 +1,134 @@
+using System;
+using System.IO.Ports;
+using System.Runtime;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using System.Windows.Forms;
+using System.Threading;
+
+namespace Gidrolock_Modbus_Scanner
+{
+    public static class Modbus
+    {
+
+        #region CRC Computation
+        static void GetCRC(byte[] message, ref byte[] CRC)
+        {
+            //Function expects a modbus message of any length as well as a 2 byte CRC array in which to 
+            //return the CRC values:
+
+            ushort CRCFull = 0xFFFF;
+            byte CRCHigh = 0xFF, CRCLow = 0xFF;
+            char CRCLSB;
+
+            for (int i = 0; i < (message.Length) - 2; i++)
+            {
+                CRCFull = (ushort)(CRCFull ^ message[i]);
+
+                for (int j = 0; j < 8; j++)
+                {
+                    CRCLSB = (char)(CRCFull & 0x0001);
+                    CRCFull = (ushort)((CRCFull >> 1) & 0x7FFF);
+
+                    if (CRCLSB == 1)
+                        CRCFull = (ushort)(CRCFull ^ 0xA001);
+                }
+            }
+            CRC[1] = CRCHigh = (byte)((CRCFull >> 8) & 0xFF);
+            CRC[0] = CRCLow = (byte)(CRCFull & 0xFF);
+        }
+        #endregion
+
+        #region Build Message
+        static void BuildMessage(byte address, byte type, ushort start, ushort registers, ref byte[] message)
+        {
+            //Array to receive CRC bytes:
+            byte[] CRC = new byte[2];
+
+            message[0] = address;
+            message[1] = type;
+            message[2] = (byte)(start >> 8);
+            message[3] = (byte)start;
+            message[4] = (byte)(registers >> 8);
+            message[5] = (byte)registers;
+
+            GetCRC(message, ref CRC);
+            message[message.Length - 2] = CRC[0];
+            message[message.Length - 1] = CRC[1];
+            string msg = BitConverter.ToString(message);
+            Console.WriteLine("Message: " + msg);
+        }
+        #endregion
+
+        #region Check Response
+        static bool CheckResponse(byte[] response)
+        {
+            //Perform a basic CRC check:
+            byte[] CRC = new byte[2];
+            GetCRC(response, ref CRC);
+            if (CRC[0] == response[response.Length - 2] && CRC[1] == response[response.Length - 1])
+                return true;
+            else
+                return false;
+        }
+        #endregion
+
+        #region Get Response
+        static void GetResponse(SerialPort port, ref byte[] response)
+        {
+            Console.WriteLine("Got response from port");
+            if (port.BytesToRead == 0)
+                return;
+            //There is a bug in .Net 2.0 DataReceived Event that prevents people from using this
+            //event as an interrupt to handle data (it doesn't fire all of the time).  Therefore
+            //we have to use the ReadByte command for a fixed length as it's been shown to be reliable.
+            for (int i = 0; i < response.Length; i++)
+            {
+                response[i] = (byte)(port.ReadByte());
+            }
+        }
+        #endregion
+
+        #region Function 3 - Read Holding Registers
+        public static async Task<bool> ReadRegAsync(SerialPort port, byte regType, byte address, ushort start, ushort registers)
+        {
+            short[] values = new short[8];
+            //Ensure port is open:
+            if (port.IsOpen)
+            {
+                //Clear in/out buffers:
+                port.DiscardOutBuffer();
+                port.DiscardInBuffer();
+                //Function 3 request is always 8 bytes:
+                byte[] message = new byte[8];
+                //Function 3 response buffer:
+                byte[] response = new byte[5 + 2 * registers];
+                //Build outgoing modbus message:
+                BuildMessage(address, (byte)3, start, registers, ref message);
+                //Send modbus message to Serial Port:
+                try
+                {
+                    await Task.Run(() => { port.Write(message, 0, message.Length); });
+                    return true;
+                }
+                catch (Exception err)
+                {
+                    MessageBox.Show(err.Message);
+                    port.Close();
+                    return false;
+                }
+            }
+            else
+            {
+                MessageBox.Show("Порт не открыт");
+                return false;
+            }
+
+        }
+        #endregion
+
+    }
+}
+