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This specification was created by a joint working group of the OPC Foundation and IO-Link Community. It defines an OPC UA Information Model to represent and access IO-Link Devices and IO-Link Masters.

OPC Foundation

OPC is the interoperability standard for the secure and reliable exchange of data and information in the industrial automation space and in other industries. It is platform independent and ensures the seamless flow of information among devices from multiple vendors. The OPC Foundation is responsible for the development and maintenance of this standard.

Initially, the OPC standard was restricted to the Windows operating system. As such, the acronym OPC was borne from OLE (object linking and embedding) for Process Control. These specifications, which are now known as OPC Classic, have enjoyed widespread adoption across multiple industries, including manufacturing, building automation, oil and gas, renewable energy and utilities, among others.

OPC UA is a platform independent service-oriented architecture that integrates all the functionality of the individual OPC Classic specifications into one extensible framework. This multi-layered approach accomplishes the original design specification goals of:

  • Platform independence: from an embedded microcontroller to cloud-based infrastructure
  • Secure: encryption, authentication, authorization and auditing
  • Extensible: ability to add new features including transports without affecting existing applications
  • Comprehensive information modelling capabilities: for defining any model from simple to complex IO-Link Community

Goal of the IO-Link Community is to develop and market IO-Link as a technology. The IO-Link Community works as a Committee C IO-Link (C) organized within the Profibus Nutzerorganisation e.V. (PNO). The IO-Link interface is in principle to be seen as being independent of the fieldbus systems of the PNO (PROFIBUS and PROFINET).

IO-Link is the first standardized IO technology worldwide (IEC 61131-9) for the communication with sensors and also actuators. The powerful point-to-point communication is based on the long established 3-wire sensor and actuator connection without additional requirements regarding the cable material. So, IO-Link is no fieldbus but the further development of the existing, tried-and-tested connection technology for sensors and actuators.

Each IO-Link device has an IODD (IO Device Description). This is a device description file which contains information about the manufacturer, article number, functionality etc. This information can be easily read and processed by the user. Each device can be unambiguously identified via the IODD as well as via an internal device ID.

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