Industrial Communication Profinet is growing “wings” Christian Gieseler Up to now, Profinet has mostly been used in factory automation. Optical fibre enable other areas to profit from this standard as well, however, e.g. the process industry and wind power. Optical fibre can be used to reliably link plants even across 100 km and more. The technical options are hardly limited at all. Author: Dipl.-Ing. Christian Gieseler, development, eks Engel GmbH & Co. KG in Wenden, Germany
Industrial Communication next page Process Field Network, in short: Profinet, is an open standard for industrial data communication based on Ethernet-TCP/IP. Profinet, including its versions CBA (component-based automation) and IO (Input-Output = local peripherals) is standardised in the standards IEC 61158 and IEC 61784. This is generally a further development of the tried and tested concept of the fieldbus system Profibus for applications where quick data communication is required via Ethernet in combination with industrial IT functions. This way, the entire range of automation all the way to cycle-synchronous motion control applications via Isochronous Real-Time (IRT) can be covered. While Profinet CBA was designed for componentbased data communication including real-time requirements in machine and plant construction, the IO-version serves to connect the local peripherals – via which components such as sensors and actuators are linked – to programmable logic controllers (PLC). The applications of Profinet IO are structured in three conformity classes, as are the requirements for the automation and network devices. The certifications are performed by a test lab accredited by the international umbrella association Profibus & Profinet International (PI). This not only ensures the respective necessary function but also that devices from different manufacturers will work together easily. Simple Project Planning of the Plants In conformity class A, only automation devices are certified; classes B and C, which mostly differ by the IRT function, also include network components. All Profinet devices must support, among others, protocols such as SNMP (Simple Network Management Protocol) and LLDP (Link Layer Discovery Protocol) – in addition to the Profinet stack through which the communication with the Profinet Controller (PLC or soft PLC) is running. In addition, the devices must be able to be integrated into automation systems such as TIA (Totally Integrated Automation) and Codesys Optical fibre can be used to reliably connect plants to a Profinet network even across very larger distances, as necessary e.g. for oil production platforms via GSDML files (General Station Description Markup Language). This way, simple project planning for the plants is possible, as well as comfortable management of a network – from configuration to diagnosis to exchange of devices. Data Rates up to 40 Gbps Both copper cables and optical fibre cables are approved for wiring of the IT infrastructure – as is Wireless LAN in conformity class A. Optical fibre are made up of a core and a jacket that are firmly connected and that only differ by the refractory index depending on type. The diameter of an optical fibre core is between 9 and 1,000 µm and may thus be ten times smaller than that of a human hair. Nevertheless, this medium is superior to the much thicker and more expensive copper cables in many respects. Data rates of up to 40 Gbps are no problem with optical fibre, and distances in excess of 100 km can be bridged easily, as mentioned above. Apart from this, light is not influenced by electrical or magnetic interferences, so that optical fibre conductors can be placed in direct proximity to power lines or other electromagnetic sources. Even lighnting strikes into the wires will not pose any danger of destruction to the connected devices. The companies combined in the Automatisierungsinitiative Deutscher Automobilhersteller (AIDA) have prescribed Profinet as a standard for networking of their plants. For data communication via optical fibre, they rely on Polymeric Optical Fibre (POF), a pure plastic fibre that can be connected without any special tools at all – the only thing needed is a sharp knife and fine-grained abrasive paper. However, POF can only bridge about 100 m, which is usually quite enough in factory automation. About Company name: eks Engel GmbH & Co. KG Headquarters: Wenden, Germany Turnover: Approx. € 5 m (2013) Employees: 33 (2014) Competence: Optical communication systems for Industrial Ethernet and fieldbus applications, project planning and services AUTOMATION TECHNOLOGIES 5/2014
