What is OPC server and client architecture?

OPC is a client/server technology. One application acts as the server providing data, and the other acts as a client using data. OPC is a widely accepted industrial communication standard that enables the exchange of data between multi-vendor devices and control applications without any proprietary restrictions.

Is OPC UA client/server architecture?

The 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.

What is a OPC client?

An OPC Client is a software module that enables applications to acquire data from an OPC Server or conduct supervisory control using an OPC Server. OPC is based on client/server architecture. OPC Client applications can be used for data acquisition.

Is OPC UA real-time?

Since being expanded with the publish-subscribe model (pub/sub) and the Time-Sensitive Networking (TSN) Ethernet standard, OPC UA is now capable of real-time communication.

Can OPC UA client Write to server?

The short answer is yes! You can write, read, and subscribe tags available on an OPC UA Server from an OPC UA Client.


OPC UA has become completely platform-independent through TCP/IP and web protocols for communication. An OPC server, which makes its data available in the network, can be addressed via these protocols.

What are OPC server?

The OPC server is a program that translates the hardware communication protocol used by a PLC into the OPC protocol. The OPC client software is a program that connects to the hardware, such as an HMI. The OPC client communicates with the OPC server to receive data or send commands to the hardware.

What is OPC server Siemens?

OPC UA – Open Platform Communications Unified Architecture For real-time communication at the field level, Siemens combines OPC UA with PROFINET – and does so in a common Industrial Ethernet network.

Is OPC UA EtherNet?

Both technologies represent data as attributes grouped in objects. EtherNet/IP represents data values as individual attributes classified with other similar attributes in an object. OPC UA is more sophisticated in that the Value attribute is one of many attributes in a node. Nodes are grouped within objects in OPC UA.

What is an OPC server architecture?

An OPC Architecture refers to a communications infrastructure that includes one or more OPC clients and OPC Servers communicating amongst each other. To keep OPC Client/OPC Server architecture diagrams easy to read it is conventional to draw data-flow diagrams with data flowing up from data sources at the bottom to data sinks at the top.

What documentation do OPC UA application developers use?

The OPC UA application developers code against the OPC UA API and therefore mainly use API documentation. Nevertheless, part 3, 4, and 5 may be of interest for application developers. The architecture of a UA application, independent of whether it is the server or client part, is structured into levels.

What is the OPC namespace for?

The OPC namespace contains the type model. Client software can verify what profiles a server supports. This is necessary to obtain information, if a server only supports DA functionality or additionally AE, HDA, etc. Additionally, information can be obtained about whether a server supports a given profile.

What is OPC UA communication stack?

This communication stack reflects the beginning of various innovations. The OPC UA architecture is a service-oriented architecture (SOA) and is based on different logical levels.