Examples - OPC UA Alarms&Conditions - Read a state of an alarm

// This example shows how to read a Low state of a limit alarm. Note that you should not normally read a state of an alarm
// from inside its event notification, because the state might have already changed. Instead, include the information you
// need in the Select clauses when subscribing for the event.
//
// Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .

using System;
using OpcLabs.EasyOpc.UA;
using OpcLabs.EasyOpc.UA.AddressSpace;
using OpcLabs.EasyOpc.UA.Navigation;

namespace UADocExamples.AlarmsAndConditions
{
    class ReadAlarmState
    {
        public static void Main1()
        {
            UAEndpointDescriptor endpointDescriptor =
                "opc.tcp://opcua.demo-this.com:62544/Quickstarts/AlarmConditionServer";

            UANodeDescriptor alarmNodeDescriptor = new UANodeId(
                namespaceUriString:"http://opcfoundation.org/Quickstarts/AlarmCondition", 
                identifier:"1:Colours/EastTank?Yellow");

            // Knowing the alarm node, and the fact that is an instance of NonExclusiveLevelAlarmType (or its subtype),
            // determine what is its LowState/Id node.
            UANodeDescriptor lowStateIdNodeDescriptor = new UABrowsePath(alarmNodeDescriptor,
                new []
                {
                    UABrowsePathElement.CreateSimple("ns=0;s=LowState"),
                    UABrowsePathElement.CreateSimple("ns=0;s=Id")
                });

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

            Console.WriteLine("Reading alarm state...");
            var lowStateId = (bool)client.ReadValue(endpointDescriptor, lowStateIdNodeDescriptor);

            Console.WriteLine($"Id of LowState: {lowStateId}");
        }
    }
}

# This example shows how to read a Low state of a limit alarm. Note that you should not normally read a state of an alarm
# from inside its event notification, because the state might have already changed. Instead, include the information you
# need in the Select clauses when subscribing for the event.
#
# 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 time

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


def eventNotification(sender, eventArgs):
    print()
    # Display the event.
    if eventArgs.EventData is None:
        print(eventArgs)
        return
    baseEventObject = eventArgs.EventData.BaseEvent
    print('Source name: ', baseEventObject.SourceName, sep='')
    print('Message: ', baseEventObject.Message, sep='')
    print('Severity: ', baseEventObject.Severity, sep='')


# Define which server we will work with.
endpointDescriptor = UAEndpointDescriptor('opc.tcp://opcua.demo-this.com:62544/Quickstarts/AlarmConditionServer')

# Instantiate the client object and hook events.
client = EasyUAClient()
client.EventNotification += eventNotification

print('Subscribing...')
IEasyUAClientExtension.SubscribeEvent(
    client,
    endpointDescriptor,
    UANodeDescriptor(UAObjectIds.Server),
    1000)

print('Processing event notifications for 30 seconds...')
time.sleep(30)

print('Unsubscribing...')
client.UnsubscribeAllMonitoredItems()

print('Waiting for 5 seconds...')
time.sleep(5)

print('Finished.')

' This example shows how to read a Low state of a limit alarm. Note that you should not normally read a state of an alarm
' from inside its event notification, because the state might have already changed. Instead, include the information you
' need in the Select clauses when subscribing for the event.
'
' Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .

Imports OpcLabs.EasyOpc.UA
Imports OpcLabs.EasyOpc.UA.AddressSpace
Imports OpcLabs.EasyOpc.UA.Navigation

Namespace AlarmsAndConditions
    Friend Class ReadAlarmState
        Public Shared Sub Main1()
            Dim endpointDescriptor As UAEndpointDescriptor =
                "opc.tcp://opcua.demo-this.com:62544/Quickstarts/AlarmConditionServer"

            Dim alarmNodeDescriptor As UANodeDescriptor = New UANodeId(
                namespaceUriString:="http://opcfoundation.org/Quickstarts/AlarmCondition",
                identifier:="1:Colours/EastTank?Yellow")

            ' Knowing the alarm node, and the fact that is an instance of NonExclusiveLevelAlarmType (or its subtype),
            ' determine what is its LowState/Id node.
            Dim lowStateIdNodeDescriptor As UANodeDescriptor = New UABrowsePath(alarmNodeDescriptor,
                New UABrowsePathElement() {
                    UABrowsePathElement.CreateSimple("ns=0;s=LowState"),
                    UABrowsePathElement.CreateSimple("ns=0;s=Id")
                })

            ' Instantiate the client object.
            Dim client = New EasyUAClient()

            Console.WriteLine("Reading alarm state...")
            Dim lowStateId = CBool(client.ReadValue(endpointDescriptor, lowStateIdNodeDescriptor))

            Console.WriteLine($"Id of LowState: {lowStateId}")
        End Sub
    End Class
End Namespace

Conceptual

Acknowledgeable Conditions - Acknowledging and Confirmation

Examples - OPC Alarms&Events

Examples - OPC Alarms&Events - Acknowledge a condition