Without any doubt, OPC UA is one of the most important standards for representing and providing access to complex data in the Industry 4.0 environment. OPC UA is a manufacturer-neutral standard that is driven by the OPC Foundation, a cross-manufacturer technology consortium. OPC UA is based on three key elements:
- Data modeling: The modeling rules can be used to create complex information models. There are also various companion standards that define model elements for specific assets or technologies.
- Security: OPC UA has built-in security mechanisms, such as encrypted data transfer and role-based access management.
- Communication: Various communication paradigms, such as client/server or pub/sub, are available for the transfer of data.
However, the complexity of OPC UA does not make it easy for new users to get started with this technology. For example, a user who only wants to implement a specific use case is faced with a number of standards, functions and models that are difficult to understand. This is the scenario that Phoenix Contact wants to prevent with its OPC UA portfolio in the context of the PLCnext Ecosystem.
We do this by providing:
- Intuitive configurability in PLC engineering as well as configuration via files for advanced users
- Trial licenses for all chargeable OPC UA components (client and pub/sub)
- A variety of simple and complex application samples for various communication scenarios
- Helpful software tools as open source
- Meaningful and intuitive documentation
All OPC UA-related PLC components (client and pub/sub licenses, as well as application examples) can be downloaded from the PLCnext Store. There is one sample package for the PLC-based client and one for pub/sub communication between PLCs. Each package contains a simple and a complex sample, as well as instructions for start-up and operation of the samples.
In the simple client sample, the client reads (subscribes to) a variable that is continuously incremented on the server side. Another variable, which is continuously decremented on the client side, is written from the client to the server. The complex client sample contains a system simulation for a remote-controlled, process-related reservoir with functions for filling, pumping and emptying the reservoir.
The simple PubSub example project contains two controllers, each of which publishes one variable and subscribes one variable. One of the variables is incremented cyclically and the other is decremented cyclically. The complex PubSub example contains system simulation for a pallet storage system and a conveyor system, which communicate with each other via OPC UA Pub/Sub.
The helpful open source software tools mentioned above can be downloaded from the PLCnext GitHub repository. Here, for example, there is the eUA_Client_Configurator_Example. This is a tool written in C# that makes it possible to create complex client configurations. The sample code repository also contains extensive instructions and documentation.
Further documentation on all topics relating to OPC UA in the PLCnext Ecosystem and the ecosystem in general is freely available in the PLCnext Infocenter.
So what are you waiting for? Get started with OPC UA and PLCnext Technology now!
