// This example shows how to read a value of a single item from the device and display its value.
//
// Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .
using System;
using OpcLabs.EasyOpc.DataAccess;
using OpcLabs.EasyOpc.OperationModel;
namespace DocExamples.DataAccess._EasyDAClient
{
partial class ReadItemValue
{
public static void DeviceSource()
{
// Instantiate the client object.
var client = new EasyDAClient();
Console.WriteLine("Reading item value...");
object value;
try
{
// DADataSource enumeration:
// Selects the data source for OPC reads (from device, from OPC cache, or dynamically determined).
// The data source (memory, OPC cache or OPC device) selection is based on the desired value age and
// current status of data received from the server.
value = client.ReadItemValue("OPCLabs.KitServer.2", "Demo.Ramp", DADataSource.Device);
}
catch (OpcException opcException)
{
Console.WriteLine("*** Failure: {0}", opcException.GetBaseException().Message);
return;
}
Console.WriteLine(value);
}
}
}
# This example shows how to read a value of a single item from the device and display its value.
#
# Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .
# OPC client and subscriber examples in Python on GitHub: https://github.com/OPCLabs/Examples-QuickOPC-Python .
# The QuickOPC package is needed. Install it using "pip install opclabs_quickopc".
import opclabs_quickopc
# Import .NET namespaces.
from OpcLabs.EasyOpc import *
from OpcLabs.EasyOpc.DataAccess import *
from OpcLabs.EasyOpc.OperationModel import *
# Instantiate the client object
client = EasyDAClient()
print('Reading item value...')
try:
# DADataSource enumeration:
# Selects the data source for OPC reads (from device, from OPC cache, or dynamically determined).
# The data source (memory, OPC cache or OPC device) selection is based on the desired value age and
# current status of data received from the server.
value = IEasyDAClientExtension.ReadItemValue(client,
ServerDescriptor('OPCLabs.KitServer.2'),
DAItemDescriptor('Demo.Single'),
DAReadParameters(DADataSource.Device))
except OpcException as opcException:
print('*** Failure: ' + opcException.GetBaseException().Message, sep='')
exit()
# Display results
print('value: ', value, sep='')
' This example shows how to read a value of a single item from the device and display its value.
'
' Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .
Imports OpcLabs.EasyOpc.DataAccess
Imports OpcLabs.EasyOpc.OperationModel
Namespace DataAccess._EasyDAClient
Partial Friend Class ReadItemValue
Public Shared Sub DeviceSource()
' Instantiate the client object.
Dim client As New EasyDAClient()
Console.WriteLine("Reading item value...")
Dim value As Object
Try
' DADataSource enumeration:
' Selects the data source for OPC reads (from device, from OPC cache, or dynamically determined).
' The data source (memory, OPC cache or OPC device) selection is based on the desired value age and
' current status of data received from the server.
value = client.ReadItemValue("OPCLabs.KitServer.2", "Demo.Ramp", DADataSource.Device)
Catch opcException As OpcException
Console.WriteLine("*** Failure: {0}", opcException.GetBaseException().Message)
Exit Sub
End Try
Console.WriteLine(value)
End Sub
End Class
End Namespace
