Real-time network OPC UA over TSN

The Ethernet standard and the future evolution of this base communication layer represents today an important standard of  interoperable network communication - in fact from sensor via control  system up to the server. According to common understanding, this will  remain so without doubt in the near and even less near future. To the  contrary, there are many doubts that the upper communication layers will  remain as they are now, since the desired deterministic and  interoperable connectivity of the future requires that only a single  protocol be used - instead of the more than 40 different ones none of  which has reached more than 50 percent market share. In addition,  communication methods are needed that require much less resources than  today which is an important prerequisite to serve the expected large  number of future nodes.

In order to obtain the mentioned interoperable connectivity, it was proposed some time ago to equip the already existing OPC UA protocol with additional features needed by industry and establish it as a  unified communication protocol of the future. OPC UA runs even on  systems that provide only a minimum of resources with respect to network  bandwidth and computing power. Deterministic communication via this  protocol shall be obtained using Time Sensitive Networking (TSN) that  currently undergoes standardization. Two important protocol additions  needed by industry that also are about to be standardized are Publish  ("Pub") and Subscribe ("Sub"). While the former is needed to  simultaneously send messages to a number of receivers, the latter allows  a program component to register for a particular event such as sensor data exceeding or falling below permissible limits to avoid polling.

In addition to the standardization of the protocols, to gain general  acceptance of this technology it also is necessary to provide a freely  accessible software implementation that can be used in an unrestricted  way. Since this currently is not not the case, the Open Source  Automation Development Lab (OSADL) in collaboration with Indian system  integrator Kalycito Infotech has launched a related Open Source software  project that is funded by Kalycito and an OSADL project group. The  already developed and further to be enhanced software is based on the  OPC UA implementation that was created in the open62541 project (ht tps://open62541.org/). The Fraunhofer Institute of Optronics, System  Technologies and Image Processing (Fraunhofer IOSB) has taken over the  activity of programming the OPC UA enhancements; this was a logical  decision, since Fraunhofer IOSB already played an important role in the  development of the original open62541 project.

The currently available results of the named project will be presented at the OSADL booth of Embedded World 2018 (hall 4, booth 168) in a  demonstrator with several TSN nodes and concurrent real-time and  non-real-time communication. The demonstrator contains a variety of TSN  hardware and software implementations of various vendors that  communicate to each other using a unified OPC UA implementation and  provides the following features for the first time under an Open Source  license that can be used in proprietary products:

 

  • Brokerless OPC UA Pub/Sub via IP multicast and the binary message encoding format according to draft of part 14 of the OPC UA specification
  • Integration of the publisher in a regular OPC UA server with additional real-time interrupting
  • Implementation of the subscribers as standalone software

 

Demonstrator hardware:
Intel Atom/I210 by TQ-Systems
FPGA-TSN by Analog Devices
FPGA-TSN Cyclone V SoC by Intel/Altera
FPGA-TSN Zync SoC by Xilinx

Software development and project management:
Fraunhofer IOSB
Kalycito Infotech
Open Source Automation Development Lab (OSADL)

Partial funding and other contributions through the following participants of the OSADL project:
Heidelberger Druckmaschinen
Kontron
Linutronix
Pilz
SICK
AMECO-kontron11

 

Contact: AMECO ltd - Distributor

Tel.: 024-36627943, www.ameco.com.vn 


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