OPC Studio User's Guide and Reference
OPC Classic Browse Path Format
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Common Fundamentals > Identifying information in OPC Classic > OPC Classic Browse Paths > OPC Classic Browse Path Format
In This Topic

In OPC Classic, the slash at the beginning of the browse path denotes an absolute path that starts from the root of the OPC address space. The string form of a browse path is a concept on the client side (OPC Studio), and does not appear in OPC specifications.

A browse path can be represented by a string; in such case, it can express either a relative or absolute browse path (the BrowsePath object cannot hold relative browse paths).

As mentioned above, the format of the browse path string is such that the individual node names are separated by slashes (“/”). The slash at the beginning of the browse path denotes an absolute path that starts from the root of the OPC address space. In addition, ‘.’ denotes a current level, and ‘..’ denotes a parent level, similarly to the conventions used in Windows file system.

Because the node names can contain any characters, we need to consider situations in which the node name itself contains a slash (‘/’) or a dot (‘.’). In such case, in the string format of browse paths, these characters are escaped by preceding them with an ampersand (‘&’). An ampersand itself needs to be escaped, too.

Examples

// This example shows how to read a single item using a browse path, and display its value, timestamp and quality.
//
// Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .

using System;
using OpcLabs.EasyOpc;
using OpcLabs.EasyOpc.DataAccess;
using OpcLabs.EasyOpc.OperationModel;

namespace DocExamples.DataAccess._EasyDAClient
{
    partial class ReadItem
    {
        public static void BrowsePath()
        {
            // Instantiate the client object.
            var client = new EasyDAClient();

            DAVtq vtq;
            try
            {
                vtq = client.ReadItem(
                    new ServerDescriptor("", "OPCLabs.KitServer.2"),
                    new DAItemDescriptor(null, "/Simulation/Random"));
            }
            catch (OpcException opcException)
            {
                Console.WriteLine("*** Failure: {0}", opcException.GetBaseException().Message);
                return;
            }

            Console.WriteLine("Vtq: {0}", vtq);
        }
    }
}

 

See Also

Examples - OPC Data Access