远程OPC已连接但无法读取

Question

I am writing a custom OPC Client application in C#, enabling reading of data from a RSLinx Server.

First of, I wasn't able to connect to the RSLINX Opc Server remotely. Exception Access Denied kept occurring.

I then alteredthe DCOM Settings of MyComputer -> Com Security -> Access Permissions and Launch and Activation Permissions, enabled everything for the User 'Everyone'

This then allowed me to connect, but when It comes to read the server I get the following exception -

[System.Runtime.InteropServices.COMException]   {"Exception from HRESULT: 0x80040202"}  System.Runtime.InteropServices.COMException

I have scoured the web as much as I possibly can, and they all boil down to Dcom related issues. I have simply tried everything with the Dcom Settings. I have made sure the settings are enabled for both MyComputer and RSLinx server.

I am using two .dll files from OPCFoundation - opcNetApi.dll , opcNetApi.Com.dll

Here is my code, (It may be handy)

private void readplc()
        {
            Opc.URL url = new Opc.URL("opcda://48.5.0.05/RSLinx OPC Server");
            Opc.Da.Server server = null;
            OpcCom.Factory fact = new OpcCom.Factory();
            server = new Opc.Da.Server(fact, null);
            try
            {
                server.Connect(url, new Opc.ConnectData(new System.Net.NetworkCredential()));
            }
            catch (Exception exy)
            {
                MessageBox.Show(exy.Message);

            }
            // Create a group
            Opc.Da.Subscription group;
            Opc.Da.SubscriptionState groupState = new Opc.Da.SubscriptionState();
            groupState.Name = "Group";
            groupState.Active = true;
            group = (Opc.Da.Subscription)server.CreateSubscription(groupState);
            // add items to the group.
            Opc.Da.Item[] items = new Opc.Da.Item[6];
            items[0] = new Opc.Da.Item();
            items[0].ItemName = "[ALARM]F20:9";
            items[1] = new Opc.Da.Item();
            items[1].ItemName = "[ALARM]F22:30";
            items[2] = new Opc.Da.Item();
            items[2].ItemName = "[ALARM]F22:6";
            items[3] = new Opc.Da.Item();
            items[3].ItemName = "[ALARM]F18:8";
            items[4] = new Opc.Da.Item();
            items[4].ItemName = "[ALARM]F22:32";
            items[5] = new Opc.Da.Item();
            items[5].ItemName = "[ALARM]F22:5";
            items = group.AddItems(items);

            try
            {

                group.DataChanged += new Opc.Da.DataChangedEventHandler(OnTransactionCompleted); // COM EXCEPTION THROWN HERE
                Console.ReadLine();

            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
                Console.ReadKey();
            }

        }




        private void OnTransactionCompleted(object group, object hReq, Opc.Da.ItemValueResult[] items)
        {

            for (int i = 0; i < items.GetLength(0); i++)
            {


            }

        }

I know for certain that the code works as I have tried building the application connecting as a localhost on the PC I am trying to remote connect to, it reads the data happily.

Hopefully, someone will have some idea what is going on, I have spent over 12 hours in the last 4 working days trying to work it out!

Answer 1

This is working for me:

_opcServer = new Server(_comFactory, null) { Url = new Opc.URL("opcda://localhost/FactoryTalk Gateway") };
_opcServer.Connect();