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Questions tagged [opc-ua]

The Open Platform Communications (OPC) Unified Architecture (UA), released in 2008, is a platform independent service-oriented architecture that integrates all the functionality of the individual OPC Classic specifications into one extensible framework. Use this tag on questions that concern Open Platform Communications Unified Architecture, in contrast to legacy OLE-based OPC.

The Open Platform Communications (OPC) Unified Architecture (UA), released in 2008, is a platform independent service-oriented architecture that integrates all the functionality of the individual OPC Classic specifications into one extensible framework.

is an interoperability standard that enables the secure and reliable exchange of industrial automation data while remaining cross-platform and vendor neutral. The specification, currently version 1.03, is developed and maintained by the OPC Foundation with the guidance of individual software developers, industry vendors, and end-users. It defines the interface between Clients and Servers, including access to real-time data, monitoring of alarms and events, historical data access, and data modeling.

From: https://projects.eclipse.org/projects/iot.milo

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862 questions
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How to write to a string tag in an OPC UA server in C#?

I am using an SDK from Unified Automation that is essentially some C# source code that creates and runs an OPC UA Server. At the moment, I am able to write only to data tags that are either initialized as integers or doubles due to the nature of the…
Conor Walsh
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Livetime / uniqueness of NodeId (How to manage NodeIds for dynamic nodes)

The Specification (Part 3: Address Space Model) of OPC UA says 5.2.2 NodeId ... A Server shall persist the NodeId of a Node, that is, it shall not generate new NodeIds when rebooting. but how can this be? NodeId is a combination from a…
Thomas
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How can I change value from a node when having a server instance (node-opcua)

I'm using node-opcua library. I have instance of OPCUAServer. How can I get node value and edit it? I assume OPC client should be able to do it, but I want to interact with OPC server since I'm responding to an internal event. Should I maybe use…
Astrowie
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How to create a OPC tag runtime

I have a Kepware OPC server and I am able to connect with my client (OPC Foundation UA lib). I created a device in Kepware and a group inside. I would like to read opc tags from the database and create them dynamically. How do I create an item with…
wh1sp3r
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How to accept/find the certificate from an opc ua server?

I am new to opc ua and not a pro in java. While setting up a client in java I'm having trouble with the certificate dealing. I want to connect to the server via Basic 256, SignAndEncrypt. As I understand, in this stage of security a certificate,…
Nanda
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OPC UA-.NETStandardLibrary: the simplest way to access historical data

I'm facing a task which is to extract historical data from an OPC system, and then store these data into a standalone database for our BI team. Although I'm a experienced developer, but I never use OPC UA before. I found the latest library provided…
Christopher
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OPC UA How to read a datatype from the server

I can't seem to figure this one out: Before writing to a tag I need to know what data type it is expecting(the value that mywrite function receives is always a string). I realise you have to read the datatype from the server and here's my code to…
Muckers Mate
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Authentication client-server in Eclipse Milo

Is-it possible in Eclipse Milo that a client connects to a server with this authentication parameters: "certificate + private key" ? And also with parameters "Security Policy" and "Message Security Mode" ? (as in UAExpert client :…
Henry198
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Call OPC-UA method with UA-.NET

I am trying to call an OPC-UA method "ReadVar" from a SINUMERIK 840d, by using the Open OPC-UA.NET implementation at https://github.com/OPCFoundation/UA-.NET I have limited knowledge about how to use this stack implementation and wonder if somebody…
E8080
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How to get OPC UA Client certificate (.NET)

I'm working on a C# client for an OPC UA server. I'm not a paying member of the OPC Foundation, so I don't have access to the SDK. I'm using the sample applications and the .NET stack that are freely available. One of the problems I'm facing is I…
Shaggydog
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OPC UA unique ID

I'm trying to build a OPC UA client application. I'd like to be able to identify a UA node uniquely in the OPC tree. I know that in OPC DA, a standard node id is a string with a '.' as a delimeter that I can use in order to identify a node. In OPC…
Idov
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OPC UA : what does installing an LDS provide?

Given these 2 installations: A machine with 3 OPC UA servers. A machine with 3 OPC UA servers and a LDS. What is the difference in functionality? In particular, I would like to know: Is the installation of a LDS mandatory? What is the practical…
Laurent LA RIZZA
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OPC UA Historical Data Access - Event History

I would like to know if there is some currently available OPC UA Client supporting Historical Data Access, more precisely for Data AND Event History. UA Expert from Unified Automation seems like to be one of the most advanced OPC UA Client, but it…
Camille G.
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OPC UA Subscription in a C# Client app doesn't trigger event handlers

I have a FactoryTalk server with some nodes and I need to monitor several attribute values. I made a client which reads and writes data succesfully, but I can't get the subscription to work. Here's the subscription configuration: subscription = new…
infradude
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UA_Client_Service_read only yields empty responses

I am trying to create a small program in C which will poll a frame of data over a opc/ua connection using the open62541 library and the forward it to a kafka server. Everything works fine when fetching the values from the nodes separately but I…
Sebastian
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