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Industrial Ethernet Book 99

Sponsor Profile 38 Ethernet POWERLINK - One Network for all applications POWERLINK is a real-time Industrial Ethernet solution designed to give users a single, consistent and integrated means for handling all communication tasks in modern automation. It is suitable for all conceivable applications in machine and plant engineering as well as for process industry applications. industrial ethernet book 04.2017 A POWERLINK NETWORK INTEGRATES all of the components used in industrial automation, from PLCs, sensors and I/O modules to actuators such as inverters, motion controllers and servo inverters, as well as hydraulics, pneumatics, safety controllers, safety sensors and actuators and HMI systems. With impressive performance characteristics including high bandwidth and fast cycle times as well as exceptional versatility, POWERLINK is perfectly suited for both centralized and decentralized automation architectures. Machines and plants with decentralized architectures give users increased flexibility for adapting and expanding, but demand a communication system that is up to the task. Free choice of topology POWERLINK offers the free choice of topology that is virtually indispensable for modular system expansion. Not least due to its excellent scalability, POWERLINK allows for limitless system expansion without negative effects on the network’s real-time performance. Unlike other real-time Industrial Ethernet systems, POWERLINK is a purely software-based open source solution that complies 100% with the IEEE 802.3 Ethernet standard. By providing such close standard compliance without any proprietary hardware, POWERLINK ensures that all of the benefits and flexibility of Ethernet technology are carried over into the real-time protocol. Users are therefore able to draw on the same standardized hardware components and use the same tools for diagnostics. Focus on pplication requirements In order to achieve real-time capability, POWERLINK relies on a highly effective mixed polling and time-slot procedure. Unlike with standard Ethernet, no arbitration is required. In the POWERLINK communication structure, one node in the network, such as a PLC, motion controller or industrial PC, is arbitrarily designated as the managing node (MN) and serves as a “moderator of the conversation”. All other devices operate as controlled nodes (CN). The MN defines the clock pulse for the synchronization of all devices and manages the data communication cycle. In the course of each cycle, the MN successively polls each CN. This polling is done via a poll request message (PReq), which additionally conveys data from the MN to the polled CN. In response, the CN then sends its own data to all other nodes by broadcasting a poll response message (PRes). This mechanism is what allows POWERLINK to achieve the fastest cross-communication available on the market. PRC and multiplexing Depending on the requirements of the application, it is possible to choose between poll response chaining (PRC) and multiplexing modes. When the cycle is run in PRC mode, the MN sends out a frame containing the output data for all CNs. The CNs respond to this signal in a time-triggered, synchronized manner and send their chained poll responses back to the MN. In applications that contain synchronized axes and temperature sensors, for example, it is possible to multiplex the network nodes. In short, POWERLINK offers the best performance for your application by optimally adapting to the requirements at hand. Maximized utilization A POWERLINK cycle consists of three periods. In the first period, the MN sends a “Start of Cycle” frame (SoC) to all CNs, which synchronizes the devices. The second period, or isochronous phase, is used for cyclic exchange of process data. The third period of a cycle is the asynchronous phase, which allows for the transfer of data packets that are not time-critical, such as TCP/IP, FTP, HTTP, parameterization data, etc. Likewise, devices that do not belong to the immediate automation level can be included in the network environment as well, as in the case of video cameras for site surveillance and access control. Moreover, a proper gateway allows for the transmission of other, non-POWERLINK fieldbus data within the asynchronous portion of a cycle, making it possible to integrate a variety of different networks. Prepared for future challenges The ability to send multiple asynchronous frames per cycle (MultiASnd) helps POWERLINK guarantee best-in-class utilization of the physical network’s bandwidth. Clearly, POWERLINK is well-prepared to meet any challenges posed by digitalization well into the future. POWERLINK is a real-time Industrial Ethernet solution designed to give users a single, consistent and integrated means for handling all communication tasks in modern automation. It is suitable for all conceivable applications in machine and plant engineering as well as for process industry applications. Perfect Complement for OPC UA The OPC Foundation and the EPSG are collaborating on interface-free communication within and between production systems and thus paving the way for digital consistency – from the sensors all the way up to the ERP level. This will be made possible by a companion specification that is now being developed by both the OPC Foundation and the EPSG. Ethernet POWERLINK Standardization Group Email: info@ethernet-powerlink.org Phone: +49 33439 539270 www.ethernet-powerlink.org


Industrial Ethernet Book 99
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