QuickOPC User's Guide and Reference
FromDevice Property (UAReadParameters)
Example 



OpcLabs.EasyOpcUA Assembly > OpcLabs.EasyOpc.UA Namespace > UAReadParameters Class : FromDevice Property
Read parameters that specify reading from the device (data source), and a default encoding.
Syntax
'Declaration
 
<DebuggerBrowsableAttribute(DebuggerBrowsableState.Never)>
<NotNullAttribute()>
Public Shared ReadOnly Property FromDevice As UAReadParameters
'Usage
 
Dim value As UAReadParameters
 
value = UAReadParameters.FromDevice
[DebuggerBrowsable(DebuggerBrowsableState.Never)]
[NotNull()]
public static UAReadParameters FromDevice {get;}
[DebuggerBrowsable(DebuggerBrowsableState.Never)]
[NotNull()]
public:
static property UAReadParameters^ FromDevice {
   UAReadParameters^ get();
}
Remarks

This set of parameters corresponds to specifying 0 to the maxAge parameter in the OPC UA Read Service request.

Example

.NET

// This example shows how to read data from the device (data source) and display a value, timestamps, and status code.

using System;
using OpcLabs.EasyOpc.UA;
using OpcLabs.EasyOpc.UA.OperationModel;

namespace UADocExamples._EasyUAClient
{
    partial class Read
    {
        public static void FromDevice()
        {
            UAEndpointDescriptor endpointDescriptor =
                "opc.tcp://opcua.demo-this.com:51210/UA/SampleServer";
            // or "http://opcua.demo-this.com:51211/UA/SampleServer" (currently not supported)
            // or "https://opcua.demo-this.com:51212/UA/SampleServer/"

            // Instantiate the client object
            var client = new EasyUAClient();

            // Obtain attribute data. By default, the Value attribute of a node will be read.
            // The parameters specify reading from the device (data source), which may be slow but provides the very latest
            // data.
            UAAttributeData attributeData;
            try
            {
                attributeData = client.Read(endpointDescriptor, "nsu=http://test.org/UA/Data/ ;i=10853", 
                    UAReadParameters.FromDevice);
            }
            catch (UAException uaException)
            {
                Console.WriteLine("*** Failure: {0}", uaException.GetBaseException().Message);
                return;
            }

            // Display results
            Console.WriteLine("Value: {0}", attributeData.Value);
            Console.WriteLine("ServerTimestamp: {0}", attributeData.ServerTimestamp);
            Console.WriteLine("SourceTimestamp: {0}", attributeData.SourceTimestamp);
            Console.WriteLine("StatusCode: {0}", attributeData.StatusCode);

            // Example output:
            //
            //Value: -2.230064E-31
            //ServerTimestamp: 11/6/2011 1:34:30 PM
            //SourceTimestamp: 11/6/2011 1:34:30 PM
            //StatusCode: Good
        }
    }
}
# This example shows how to read data from the device (data source) and display a value, timestamps, and status code.

# The QuickOPC package is needed. Install it using "pip install opclabs_quickopc".
import opclabs_quickopc

# Import .NET namespaces.
from OpcLabs.EasyOpc.UA import *
from OpcLabs.EasyOpc.UA.OperationModel import *


# Instantiate the client object.
client = EasyUAClient()

# Obtain attribute data. By default, the Value attribute of a node will be read.
# The parameters specify reading from the device (data source), which may be slow but provides the very latest
# data.
try:
    attributeData = IEasyUAClientExtension.Read(client,
        UAEndpointDescriptor('opc.tcp://opcua.demo-this.com:51210/UA/SampleServer'),
        UANodeDescriptor('nsu=http://test.org/UA/Data/ ;i=10853'),
        UAReadParameters.FromDevice)
except UAException as uaException:
    print('*** Failure: ' + uaException.GetBaseException().Message)
    exit()

# Display results.
print('Value: ', attributeData.Value)
print('ServerTimestamp: ', attributeData.ServerTimestamp)
print('SourceTimestamp: ', attributeData.SourceTimestamp)
print('StatusCode: ', attributeData.StatusCode)
Requirements

Target Platforms: .NET Framework: Windows 10 (selected versions), Windows 11 (selected versions), Windows Server 2016, Windows Server 2022; .NET: Linux, macOS, Microsoft Windows

See Also