OPC Kepware and C#

Recently, I have received many question about How to connect OPC to C# .
These are a good instruction for you. Following step by step, you can easily finish your project. 

Good luck !!!!!!!!

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using OPCAutomation;




namespace OPC2
{
    public partial class Form1 : Form
    {
        public OPCAutomation.OPCServer AnOPCServer;
        public OPCAutomation.OPCServer ConnectedOPCServer;
        public OPCAutomation.OPCGroups ConnectedServerGroup;
        public OPCAutomation.OPCGroup ConnectedGroup;
        public string Groupname;

        int ItemCount;
        Array OPCItemIDs = Array.CreateInstance(typeof(string), 10);
        Array ItemServerHandles = Array.CreateInstance(typeof(Int32), 10);
        Array ItemServerErrors = Array.CreateInstance(typeof(Int32), 10);
        Array ClientHandles = Array.CreateInstance(typeof(Int32), 10);
        Array RequestedDataTypes = Array.CreateInstance(typeof(Int16), 10);
        Array AccessPaths = Array.CreateInstance(typeof(string), 10);
        Array WriteItems = Array.CreateInstance(typeof(string), 10);
        
        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            
        }

        private void btnConnect_Click(object sender, EventArgs e)
        {
            try
            {
                string IOServer = "Kepware.KEPServerEX.V5";
                string IOGroup = "OPCGroup1";

                ConnectedOPCServer = new OPCAutomation.OPCServer();
                ConnectedOPCServer.Connect(IOServer, "");
                ConnectedGroup = ConnectedOPCServer.OPCGroups.Add(IOGroup);
                ConnectedGroup.DataChange += new DIOPCGroupEvent_DataChangeEventHandler(ObjOPCGroup_DataChange);
                ConnectedGroup.UpdateRate = 1000;
                ConnectedGroup.IsSubscribed = ConnectedGroup.IsActive;


                ItemCount = 2;
                OPCItemIDs.SetValue("Channel2.Device1.R1", 1);
                ClientHandles.SetValue(1, 1);
                OPCItemIDs.SetValue("Channel2.Device1.R2", 2);
                ClientHandles.SetValue(2, 2);

                ConnectedGroup.OPCItems.DefaultIsActive = true;
                ConnectedGroup.OPCItems.AddItems(ItemCount, ref OPCItemIDs, ref ClientHandles, out ItemServerHandles, out ItemServerErrors, RequestedDataTypes, AccessPaths);
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.ToString());
            }

        }

        private void btnDisconnect_Click(object sender, EventArgs e)
        {
            ConnectedOPCServer.Disconnect();
        }

        private void ObjOPCGroup_DataChange(int TransactionID, int NumItems, ref Array ClientHandles, ref Array ItemValues, ref Array Qualities, ref Array TimeStamps)
        {
            try
            {
                for (int i = 1; i <= NumItems; i++)
                {
                    if ((Convert.ToInt32(ClientHandles.GetValue(i)) == 1))
                    {
                        textBox1.Text = ItemValues.GetValue(i).ToString();
                    }
                    if ((Convert.ToInt32(ClientHandles.GetValue(i)) == 2))
                    {
                        textBox2.Text = ItemValues.GetValue(i).ToString();
                    }
                }
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.ToString());
            }
        }

        private void textBox1_TextChanged(object sender, EventArgs e)
        {
            
        }

        private void btnWrite1_Click(object sender, EventArgs e)
        {
            try
            {
                WriteItems.SetValue(textBox4.Text, 1);
                ConnectedGroup.SyncWrite(ItemCount, ref ItemServerHandles, ref WriteItems, out ItemServerErrors);
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.ToString());
            }

        }

    }
}

Watch more about communication between
 PLC and C#, without OPC:  

https://youtu.be/PruLwQsBX_M

P/s: Nếu bạn gặp lỗi khi add dll thì theo code project

 The files myOPC.dll and Interop.OPCAutomation.dll both should 

be referenced by your client file and their properties "Copy Local" set to true. 

and more My project - Youtube