OPC是Object Linking and Embedding(OLE)forProcess Control的缩写,它是微软公司的对象连接和嵌入技术在过程控制方面的应用。OPC以OLE/COM/DCOM技术为基础,采用客户/服务器模式,为工业自动化软件面向对象的开发提供了统一的标准,这个标准定义了应用Microsoft操做系统在基于PC的客户机之间交换自动化实时数据的方法,采用这项标准后,硬件开发商将取代软件开发商为本身的硬件产品开发统一的OPC接口程序,而软件开发者可免除开发驱动程序的工做,充分发挥本身的特长,把更多的精力投入到其核心产品的开发上。编程
SimaticNet是西门子全集成自动化系统中的一个重要组成部分,它为完善的工业自动化控制系统的通信提供部件和网络,同时提供多个OPCServer,为数据的外部访问提供接口,本文主要以OPC.SimaticNET为例说明。数组
90年代OPC基金会开发了一系列的通信接口好比 Data Access (DA), Alarm & Events (A&E), Historical Data Access (HDA) and Data eXchange (DX),统称传统OPC。今天主要使用的OPC DA通信方式,这个在1995年左右仍是很流行的方法,最近几年OPC Foundation又开发了新的 OPC Unified Architecture (UA) 标准,更好的适应了工业4.0。关于传统OPC和OPC UA的区别,后面会单独来讲。安全
许多OPC服务器,包括OPC.SimaticNet,是在COM平台开发的,从而对于基于.NET框架下的C#语言,做为客户端程序语言访问OPCServer,须要解决两个平台间无缝迁移的问题。OPC基金会对会员提供了OpcRcw动态连接库,OPC NET COM 包装器和OPC NET API,将OPC复杂的规范封状成简单易用的C#类 ,能够比较容易地实现数据访问。服务器
OPC主要包含两种接口:CUSTOM标准接口和OLE自动化标准接口,自定义接口是服务商必须提供的,而自动化接口则是可选的。
自定义接口是一组COM接口,主要用于采用C++语言的应用程序开发;
自动化接口是一组OLE接口,主要用于采用VB,DELPHI,Excel等基于脚本编程语言的应用程序开发。本文是使用C#经过自动化接口来实现的,也是最简单的方式。网络
首先必须了解的是OPC服务器的对象模型:app


程序中涉及到的重要方法和属性比较多,解释下几个容易搞混的:框架
OPCItem 对象的属性ServerHandle,只读属性,服务器提供给Item的句柄,经过此句柄,Client能够定位到此Item,来对此Item进行后续的操做,好比移动删除;编程语言
OPCItem 对象的属性ClientHandle,可读可写属性,客户端分配给Item的句柄,这个句柄能够手动设置,也可由.NET随机选取的,不须要咱们来设置,而且每次运行时,这
个句柄都不一样,相似于TCP scoket通信中的Client端分配的端口号。Server端必须指定端口号,Client端随机生成,每次都不同。测试
OPCGroup 对象的属性的IsSubscribed,可读可写属性,Group的IsSubscribed为True,此Group才能开始接受服务器的数据属性,此Group才能被订阅。ui
OPCGroup 对象的事件DataChange (TransactionID As Long, NumItems As Long, ClientHandles() As Long,ItemValues() As Variant, Qualities() As Long, TimeStamps() As Date)须要注意的是NumItems参数是每次事件触发时Group中实际发生数据变化的Item的数量,而不是整个Group里的Items.
OPCGroup 对象的属性UpdateRate,可读可写属性,规定了数据刷新的周期,单位milliseconds.注意的是,不是设定多少ms,实际就是多少,好比给定53ms,OPC server会就近选择50ms.有区间划分的。
源程序以下:
[csharp] view plain copy


- using System;
- using System.Collections.Generic;
- using System.ComponentModel;
- using System.Data;
- using System.Drawing;
- using System.Text;
- using System.Windows.Forms;
-
- using System.Net;
- using OPCAutomation;
-
-
- namespace OpcClient
- {
- public partial class OpcClient : Form
- {
- public OpcClient()
- {
- InitializeComponent();
- }
-
- #region 私有变量
- private String strHostIP;
- private String strHostName;
- private Boolean opc_connected;
-
- private OPCServer LocalServer;
- private OPCGroups myGroups;
- private OPCGroup myGroup;
- private OPCGroup myGroup1;
- private OPCItems myItems;
- private OPCItems myItems1;
- private OPCItem myItem;
- int itmHandleClient = 0; /// 客户端句柄
- int itmHandleServer = 0; /// 服务端句柄
- //**wfx
- private OPCItem [] myItemArray;
- private OPCItem[] myItemArray1;
-
- #endregion
-
- #region 私有方法
- /// <summary>
- /// 链接OPC服务器
- /// </summary>
- /// <param name="remoteServerIP">OPCServerIP</param>
- /// <param name="remoteServerName">OPCServer名称</param>
- private bool ConnectRemoteServer(string remoteServerIP, string remoteServerName)
- {
- try
- {
- LocalServer.Connect(remoteServerName, remoteServerIP);
-
- if (LocalServer.ServerState == (int)OPCServerState.OPCRunning)
- {
- lblState.Text = "已链接到:" + "\r\n" + LocalServer.ServerName + "\r\n";
- //显示服务器信息
- lblState.Text = lblState.Text + "开始时间:" + "\r\n" + LocalServer.StartTime.ToString() + "\r\n";
- lblState.Text = lblState.Text + "版本:" + LocalServer.MajorVersion.ToString() + "." + LocalServer.MinorVersion.ToString() + "." + LocalServer.BuildNumber.ToString();
- }
- else
- {
- //这里你能够根据返回的状态来自定义显示信息,请查看自动化接口API文档
- lblState.Text = "状态:" + LocalServer.ServerState.ToString() + "\r\n";
-
- }
- }
- catch (Exception err)
- {
- MessageBox.Show("链接远程服务器出现错误:" + err.Message, "提示信息", MessageBoxButtons.OK, MessageBoxIcon.Warning);
- return false;
- }
- return true;
- }
-
- /// <summary>
- /// 每当项数据有变化时执行的事件
- /// </summary>
- /// <param name="TransactionID">处理ID</param>
- /// <param name="NumItems">项个数</param>
- /// <param name="ClientHandles">项客户端句柄</param>
- /// <param name="ItemValues">TAG值</param>
- /// <param name="Qualities">品质</param>
- /// <param name="TimeStamps">时间戳</param>
- void myGroup_DataChange(int TransactionID, int NumItems, ref Array ClientHandles, ref Array ItemValues, ref Array Qualities, ref Array TimeStamps)
- {
- //为了测试,因此加了控制台的输出,来查看事物ID号
- Console.WriteLine("********"+TransactionID.ToString()+NumItems.ToString()+"*********");//第二次进来后为啥变成1了,以前都是4个
- //**wfx
- /*
- for (int i = 1; i <= NumItems; i++)
- {
- this.txtValue.Text = ItemValues.GetValue(i).ToString();
- this.txtQuality.Text = Qualities.GetValue(i).ToString();
- this.txtTime.Text = TimeStamps.GetValue(i).ToString();
- }
- */
- //**wfx
- TextBox[] tb = new TextBox[4];
- tb[0] = textBox1;
- tb[1] = textBox2;
- tb[2] = textBox3;
- tb[3] = textBox4;
- //ClientHandles.GetValue(i);
- for (int i = 1; i <= NumItems;i++ )
- {
- tb[(int)ClientHandles.GetValue(i)-1].Text = ((float)ItemValues.GetValue(i)).ToString("0.00");
- }
- }
-
- /// <summary>
- /// 写入TAG值时执行的事件
- /// </summary>
- /// <param name="TransactionID"></param>
- /// <param name="NumItems"></param>
- /// <param name="ClientHandles"></param>
- /// <param name="Errors"></param>
- void myGroup_AsyncWriteComplete(int TransactionID, int NumItems, ref Array ClientHandles, ref Array Errors)
- {
- lblState.Text = "";
- for (int i = 1; i <= NumItems; i++)
- {
- lblState.Text += "TransactionID:" + TransactionID.ToString() + "\r\n" + "ClientHandle:" + ClientHandles.GetValue(i).ToString() + "\r\n" + "ErrorValue: " + Errors.GetValue(i).ToString() + "\r\n";
- }
- }
-
- /// <summary>
- /// 建立组
- /// </summary>
- private bool CreateGroup()
- {
- try
- {
- myGroups = LocalServer.OPCGroups;
- myGroup = myGroups.Add("OpcDotNetGroup");
- myGroup1 = myGroups.Add("OpcDotNetGroup1");
- SetDefaultGroupProperty();
- myItems = myGroup.OPCItems;
- myItems1 = myGroup1.OPCItems;
- //**wfx
- myItemArray =new OPCItem [16];
- myItemArray1 = new OPCItem[16];
- //**add items
- //DA格式 S7:[S7 connection_1]MX3.1
- //S7:[S7 connection_1]DB1,X3.0
- //OPC UA格式 S7:S7 connection_1.db5.68,r
- //S7:S7 connection_1.db1.20,x7
- myItemArray[0] = myItems.AddItem("S7:[S7 connection_1]db5,real68", 1);//Z轴
- myItemArray[1] = myItems.AddItem("S7:[S7 connection_1]db1,real50", 2);//刮刀
- myItemArray[2] = myItems.AddItem("S7:[S7 connection_1]db1,real96", 3);//送粉
- myItemArray[3] = myItems.AddItem("S7:[S7 connection_1]db1,real72", 4);//温度
- //**wfx
- /*
- myItemArray1[4] = myItems1.AddItem("S7:[S7 connection_1]MX3.1", 4);//Z 正
- myItemArray1[5] = myItems1.AddItem("S7:[S7 connection_1]MX3.6", 5);//Z 负
- */
- myGroup.DataChange += new DIOPCGroupEvent_DataChangeEventHandler(myGroup_DataChange);
- myGroup.AsyncWriteComplete += new DIOPCGroupEvent_AsyncWriteCompleteEventHandler(myGroup_AsyncWriteComplete);
-
- }
- catch (Exception err)
- {
- MessageBox.Show("建立组出现错误:" + err.Message, "提示信息", MessageBoxButtons.OK, MessageBoxIcon.Warning);
- return false;
- }
- return true;
- }
-
- /// <summary>
- /// 设置缺省的组属性
- /// </summary>
- private void SetDefaultGroupProperty()
- {
- LocalServer.OPCGroups.DefaultGroupIsActive = true ;
- LocalServer.OPCGroups.DefaultGroupDeadband = 0 ;
- myGroup.UpdateRate = 250 ;
- myGroup.IsActive = true ;
- myGroup.IsSubscribed = true ;
- myGroup1.UpdateRate = 250;
- myGroup1.IsActive = true;
- myGroup1.IsSubscribed = true;
- }
-
-
- #endregion
-
- #region 窗体事件
-
- //窗体载入时,查询本机安装的OPC Server 列表
- private void OpcClient_Load(object sender, EventArgs e)
- {
-
-
- //获取本地计算机IP,计算机名称
- IPHostEntry IPHost = Dns.GetHostEntry(Environment.MachineName);
- IPHost.HostName.ToString();
- if (IPHost.AddressList.Length > 0)
- {
- strHostIP = IPHost.AddressList[0].ToString();
- }
- else
- {
- return;
- }
- //经过IP来获取计算机名称,可用在局域网内
- IPHostEntry ipHostEntry = Dns.GetHostEntry(strHostIP);
- strHostName = ipHostEntry.HostName.ToString();
-
- //获取本地计算机上的OPCServerName
- try
- {
- LocalServer = new OPCServer();
- object serverList = LocalServer.GetOPCServers(strHostName);
-
- foreach (string turn in (Array)serverList)
- {
- cmbServer.Items.Add(turn);
- }
-
- cmbServer.SelectedIndex = 0;
- btnConnect.Enabled = true;
- }
- catch (Exception err)
- {
- MessageBox.Show("枚举本地OPC服务器出错:" + err.Message, "提示信息", MessageBoxButtons.OK, MessageBoxIcon.Warning);
- }
-
- }
-
-
- //点击"链接"按钮, 动做
- private void btnConnect_Click(object sender, EventArgs e)
- {
- //链接服务器
- try
- {
- if (!ConnectRemoteServer("127.0.0.1", cmbServer.Text))
- {
- return;
- }
-
- opc_connected = true; //已链接标记
-
- OPCBrowser oPCBrowser = LocalServer.CreateBrowser();
- //展开分支
- oPCBrowser.ShowBranches();
- //展开叶子
- oPCBrowser.ShowLeafs(true);
- lstItems.Items.Clear(); //清空列表
- foreach (object turn in oPCBrowser)
- {
- lstItems.Items.Add(turn.ToString());
- }
-
- if (!CreateGroup())
- {
- return;
- }
- }
- catch (Exception err)
- {
- MessageBox.Show("初始化出错:" + err.Message, "提示信息", MessageBoxButtons.OK, MessageBoxIcon.Warning);
- }
-
- }
-
-
-
-
- /// 选择列表中的某个Item时处理的事情
- private void lstItems_SelectedIndexChanged(object sender, EventArgs e)
- {
- try
- {
- this.txtName.Text = lstItems.SelectedItem.ToString();
- if (itmHandleClient != 0)
- {
- this.txtValue.Text = "";
- this.txtQuality.Text = "";
- this.txtTime.Text = "";
-
- Array Errors;
- OPCItem bItem = myItems.GetOPCItem(itmHandleServer);
- //注:OPC中以1为数组的基数
- int[] temp = new int[2] { 0, bItem.ServerHandle };
- Array serverHandle = (Array)temp;
- //移除上一次选择的项
- myItems.Remove(myItems.Count, ref serverHandle, out Errors);
- }
- itmHandleClient = 1234;
- myItem = myItems.AddItem(lstItems.SelectedItem.ToString(), itmHandleClient);
- itmHandleServer = myItem.ServerHandle;
- Console.WriteLine("*****" + itmHandleServer+"*****");//ServerHandle是随机分配,比如Socket的客户端端口号也是随机分配同样,ClientHandle是用户指定,
- }
- catch (Exception err)
- {
- //没有任何权限的项,都是OPC服务器保留的系统项,此处可不作处理。
- itmHandleClient = 0;
- txtValue.Text = "Error ox";
- txtQuality.Text = "Error ox";
- txtTime.Text = "Error ox";
- MessageBox.Show("此项为系统保留项:" + err.Message, "提示信息");
- }
- }
-
-
- //点击"写入"按钮
- private void cmdWrite_Click(object sender, EventArgs e)
- {
- OPCItem bItem = myItems.GetOPCItem(itmHandleServer);
- int[] temp = new int[2] { 0, bItem.ServerHandle };
- Array serverHandles = (Array)temp;
- object[] valueTemp = new object[2] { "", txtNewValue.Text };
- Array values = (Array)valueTemp;
- Array Errors;
- int cancelID;
- myGroup.AsyncWrite(1, ref serverHandles, ref values, out Errors, 2009, out cancelID);
- //myItem.Write(txtNewValue.Text);//这句也能够写入,但并不触发写入事件
- GC.Collect();
- }
-
-
- //点击"断开" 按钮
- private void btnDisConn_Click(object sender, EventArgs e)
- {
- if (!opc_connected)
- {
- return;
- }
-
- if (myGroup != null)
- {
- myGroup.DataChange -= new DIOPCGroupEvent_DataChangeEventHandler(myGroup_DataChange);
- }
-
- if (LocalServer != null)
- {
- LocalServer.Disconnect();
- //LocalServer = null;
-
- }
-
- opc_connected = false;
- lstItems.Items.Clear();
-
- //显示信息
- lblState.Text = "已经从OPC服务器断开." + "\r\n" ;
- //显示服务器信息
- lblState.Text = lblState.Text + "断开时间:" + "\r\n" + System.DateTime.Now.ToString() + "\r\n";
-
- }
-
-
-
-
- //关闭窗体时候,清理工做
- private void OpcClient_FormClosing(object sender, FormClosingEventArgs e)
- {
- btnDisConn_Click(new Object(),new EventArgs());
- }
-
- #endregion
-
- private void button1_Click(object sender, EventArgs e)
- {
- myItemArray1[6] = myItems1.AddItem("S7:[S7 connection_1]db1,x0.3", 6);//刮刀正
- myItemArray1[10] = myItems1.AddItem("S7:[S7 connection_1]db1,real41", 10);//刮刀速度
- myItemArray1[11] = myItems1.AddItem("S7:[S7 connection_1]db1,real33", 11);//刮刀位置
-
- int[] temp = new int[4] { 0, myItemArray1[6].ServerHandle, myItemArray1[10].ServerHandle, myItemArray1[11].ServerHandle };
- Array serverHandles = (Array)temp;
- object[] valueTemp = new object[4] { "", true, textBox6.Text, textBox7.Text };
- Array values = (Array)valueTemp;
- Array Errors;
- int cancelID;
- myGroup1.AsyncWrite(3, ref serverHandles, ref values, out Errors, 2009, out cancelID);
- //myItem.Write(txtNewValue.Text);//这句也能够写入,但并不触发写入事件
-
- }
-
- private void button2_Click(object sender, EventArgs e)
- {
- myItemArray1[7] = myItems1.AddItem("S7:[S7 connection_1]db1,x0.7", 7);//刮刀负
- myItemArray1[10] = myItems1.AddItem("S7:[S7 connection_1]db1,real41", 10);//刮刀速度
- myItemArray1[11] = myItems1.AddItem("S7:[S7 connection_1]db1,real33", 11);//刮刀位置
-
- int[] temp = new int[4] { 0, myItemArray1[7].ServerHandle, myItemArray1[10].ServerHandle, myItemArray1[11].ServerHandle };
- Array serverHandles = (Array)temp;
- object[] valueTemp = new object[4] { "", true, textBox6.Text, textBox7.Text };
- Array values = (Array)valueTemp;
- Array Errors;
- int cancelID;
- myGroup1.AsyncWrite(3, ref serverHandles, ref values, out Errors, 2009, out cancelID);
- //myItem.Write(txtNewValue.Text);//这句也能够写入,但并不触发写入事件
- }
-
- private void button3_Click(object sender, EventArgs e)
- {
- int[] temp = new int[4] { 0, myItemArray[8].ServerHandle, myItemArray[12].ServerHandle, myItemArray[13].ServerHandle };
- Array serverHandles = (Array)temp;
- object[] valueTemp = new object[4] { "", true, textBox8.Text, textBox9.Text };
- Array values = (Array)valueTemp;
- Array Errors;
- int cancelID;
- myGroup.AsyncWrite(3, ref serverHandles, ref values, out Errors, 2009, out cancelID);
- //myItem.Write(txtNewValue.Text);//这句也能够写入,但并不触发写入事件
- }
-
- private void button4_Click(object sender, EventArgs e)
- {
- int[] temp = new int[4] { 0, myItemArray[9].ServerHandle, myItemArray[12].ServerHandle, myItemArray[13].ServerHandle };
- Array serverHandles = (Array)temp;
- object[] valueTemp = new object[4] { "", true, textBox8.Text, textBox9.Text };
- Array values = (Array)valueTemp;
- Array Errors;
- int cancelID;
- myGroup.AsyncWrite(3, ref serverHandles, ref values, out Errors, 2009, out cancelID);
- //myItem.Write(txtNewValue.Text);//这句也能够写入,但并不触发写入事件
- }
-
- }
- }

最后,从总体上说下OPC DA的协议规范,OPC DA是在WINDOWS的COM/DOM技术上定义的接口定义,在TCP IP七层模型的最高层应用层,决定了它必须运行在WINDOWS平台,不可以跨平台,灵活性和安全性不如OPC UA,由于OPC DA的会话层和表示层用户是有权利来使用的。对比OPC DA 和OPC UA的协议规范以下:更多不一样点,后面会单独再说。

