Electricity and Control December 2023

INDUSTRY 4.0 + IIOT

EtherCAT – a leader in industrial communications technology EtherCAT technology has demonstrated its value in practice as a high-performance real time Ethernet technology for 20 years.The communication system, developed by Beckhoff, was first introduced to the market at Hannover Messe 2003 and has been an international standard since 2007. It is also an open technology – and widely used. At a recent breakfast seminar hosted by Beckhoff in Johannesburg, Martin Rostan, Executive Director of the EtherCATTechnology Group, set out the benefits of EtherCAT and explained the structure of the technology that gives it the edge. Leigh Darroll reports some of the highlights from Rostan’s presentation here, together with additional informa tion from the EtherCAT Technology Group (ETG).

Martin Rostan, Executive Director, EtherCAT Technology Group.

R ostan began his presentation by highlighting why the bus system, as the basis for communications in automation, is so important. The bus system, he pointed out, is the core of the control architecture. It is the bus system that defines: the control system’s performance, the choice of suppliers and com ponents, the overall cost of the control system (especially if there are only a few suppliers), and whether the user has the option of centralised control or not. Superfast controls, as in PC-based controls, require a su perfast bus technology, and this is where EtherCAT excels. Network performance Rostan noted some particular advantages that EtherCAT offers, compared to other well-established technologies like Ethernet IP and PROFINET. For one, it is faster. It ena bles significantly reduced reaction times within the control system. Precise synchronisation is another advantage, en abled by the distributed clocks incorporated into the tech nology. Further, EtherCAT Bridges provide for automatic synchronisation of several or multiple networks. EtherCAT’s key functional principle lies in how its nodes process Ethernet frames: each node reads the data ad dressed to it and writes data back to the frame all while the frame is moving downstream. This leads to improved band width use and eliminates the need for switches and hubs.

The way EtherCAT processes frames makes it the fastest Industrial Ethernet technology – and the ‘engineer’s choice’ for many applications – and it synchronises with an accuracy of less than a microsecond. This is a major benefit for all appli cations in which the target system is controlled or measured via the bus system. The fast reaction times work to reduce the wait times in the transitions between process steps, which significantly improves application efficiency. Furthermore, the EtherCAT system architecture typically reduces the load on the CPU by 25 to 30% in comparison to other bus sys tems (given the same cycle time). When optimally applied, EtherCAT’s performance leads to improved accuracy, greater throughput, and thus to lower costs of production. Flexible topology Additionally, EtherCAT wiring is more flexible, supporting various topologies. As an increasingly preferred option, EtherCAT P cabling combines communications and power in one cable. In EtherCAT applications, the machine structure deter mines the network topology, not the other way around. In conventional Industrial Ethernet systems, there are gen erally limitations on how many switches and hubs can be cascaded, which, in turn, limits the overall network topolo gy. As EtherCAT does not need hubs or switches, there are no such limitations. With EtherCAT, line, tree, or star net-

EtherCAT’s key functional principle lies in how its nodes process Ethernet frames – and this makes it the fastest Industrial Ethernet technology.

Flexible wiring allows for different network topologies – line, tree, star, or any combination of these.

4 Electricity + Control DECEMBER 2023