By Dr. Andreas Weder, Fraunhofer IPMS
Ethernet has been equally established as a dependable wired solution in both computer and automation networks. The open standard allows terminals to be quickly and simply connected as well as easily scaled to exchange data with relatively inexpensive hardware.
Ethernet was, however, not originally designed to meet the requirements posed by automation technology, particularly in regards to guaranteed and real-time communication. Therefore, various bus systems in automation have evolved using Ethernet on a physical level while implementing proprietary real-time protocols on top. These systems often lead to the exclusive use of the network infrastructure as well as vendor dependencies. Such networks handling time-critical data traffic are today separated from networks directing less-critical data traffic in order to eliminate reciprocal negative interference.
In the future, Industry 4.0 applications will require increasingly more consistent Ethernet networks. Such networks can only be produced at great cost with the traditional structure. Time-Sensitive networking (TSN) provides a solution aiming to change these current conditions.
Guarantees regarding cycle times and fluctuations in cycle times are prerequisite for a range of application fields in automation, including, for example, drive, control, and conveyor technology. The data transfer times demanded in these application fields are significantly less than 1 ms.
In addition to these applications requiring “hard” real-time capability, other applications such as process automation implement “soft” real-time capability with longer cycle times. Nevertheless guaranteed latencies are required for these applications as well. Various real-time communication methods such as EtherCat or Profinet IRT have been specially developed to provide guaranteed cycle times. Although they are based on conventional Ethernet, they are not compatible with each other. This incompatibility has resulted in fragmented networks.
Download the PDF to continue with:
• Why TSN?
• Important Core Elements
• TSN IP Core on FPGA Basis
• Summary and Outlook
Or go to the TSN_CTRL TSN Ethernet Subsystem product page.