INDUSTRIAL COMMUNICATION NETWORKS

By the time now, the networks should not be missed in the automation world to operate a plant as well as possible. The industrial networks bring a high flexibility to the control systems, they lower the costs of cabling, they provide new capabilities in controlling and in surveying the automated plants. All that for the benefits of the operators, of the maintenance teams, of the the production and of the management all together.

The various automated applications are operating in many very different contexts, with specific constraints and requirements. Consequently, for historical reasons, for economical reasons and for technical reasons, the amount of solutions in industrial networking is superabundant.

Some of these solutions became standards and continue to evolve, others answer to specific markets, and still others come from manufacturers who want to impose their own solutions. Some other solutions in industrial networking did not know how to evolve or could not, and became anecdotal or simply disappear. The new technologies applied to networking incline the manufacturers to offer new solutions, with higher performances, with lower costs or with higher flexibility. That leads the users to imagine new applications using these techniques.

This folder offers a selection of resources in relation with the networks and the digital communication techniques in general ( the basics, the protocols, the technologies, the topologies, the architectures and more ). It also offers introductions of the most used digital industrial networks ( Ethernet, field buses or sensors and actuators networks for instance ),with a selection of technical papers and specifications.

This introduction to the networks lists a set of technical papers reporting on the basic knowledge in data transmissions, in communication protocols, in the different technologies in usage, in the networks performances, in servers, in switching, in machine to machine ( M2M ) data exchanges and more. These websites present fundamental knowledge and basics on data transmission and digital communication engineering, various standards and some various technologies in use.

• Introduction to common digital networking.

  Tutorials about fundamental concepts.

• Introduction to industrial networks.

  Technology overview, introduction to industrial field communication buses.

Some protocols in usage to communicate through the networks are not attached to a precise technology. They are being used as data interface and are not dependent of a specific hardware. They can be encapsulated in other protocols, consequently they can use many different structures to transport the data.

• OPC - Open platform communication interface.

  Technical presentations, architecture, specifications, resources.

• DNP3 - Distributed network protocol.

  Introduction to the technology, example of a concrete application.

The Ethernet technologies are taking more and more importance in networking applied to the industry, because of its popularity, because of its low cost and because of its features. Ethernet solutions especially dedicated to the industrial world have appeared to improve the basic specifications of Ethernet, with better responses to some constraints such as performances, real-time capabilities, shorter response times and more.

• Essential knowledge.

  Resources, introduction to the basic protocol and to the Internet protocol.

• Industrial Ethernet digital networks.

  Introduction to the standard plus technical articles.

• Real time and determinism.

  ISO 1588 introduction.

• Fast Ethernet.

  Technology overview.

• Gigabit Ethernet / 10 Gigabits Ethernet.

  Basics, segmentation and performances.

• Utilities.

  Protocol and traffic analyzers.

The field networks are the common networks used in the workshop ( down to the field ), to exchange data with sensors, with actuators, with programmable controllers ( PLC ), with operator panels ( MMI ) or with SCADA systems. After having read our field bus definition, you will find here introductions and technical papers about some well known field buses. Some of them are now obsolete, but these got a quite important notoriety in the past and they were seriously involved in the evolution of the industrial networking technologies.

• Arcnet.

  Token local area network.

• BitBus ( IEEE 1118 ).

  Non proprietary local open network.

• CC-link.

  Control and communication link.

• CIP.

  Common industrial protocol.

• Ethernet IP.

  Industrial Ethernet protocol.

• Fieldbus foundation.

  Standardized field bus.

• FIP.

  Factory instrumentation protocol.

• Modbus.

  De facto standard industrial communication protocol.

• Profibus.

  Proprietary local network.

• Profinet.

  Profibus over Ethernet.

• Safety bus / SafetyNet.

  Safety dedicated field data buses.

The control buses are specialized networks with high performances providing « real time » features with short response time, and sometimes deterministic capabilities. They are used for motion control applications, axes control applications or robotic applications for instance. Most of the time, the protocols used by these networks offer a specialized and standardized interface in order to exchange the data.

• CAN bus.

  Programmable systems network.

• ControlNet.

  Real time deterministic network.

• Drivecom.

  Frequency inverter communication interface.

• Ethercat.

  Automated control Ethernet protocol.

• MACRO.

  Multiaxes controller network real-time protocol.

• Mechatrolink.

  Axes control field bus.

• Powerlink.

  Deterministic and real-time Ethernet protocol.

• Profidrive.

  Profinet for the frequency drives.

• Sercos.

  Inverter network real-time protocol.

• Synqnet.

  Fast Ethernet network for EOM manufacturers.

The instruments networks answer to specific needs to exchange data between instruments, smart sensors and other « intelligent » devices and interfaces. They allow to exchange data easily and remotely for configuration, adjustments, calibration and diagnostics.

• Din Messbus - Standard measurement bus.

  Master / slave measurement bus.

• GPIB ( IEEE 488 ) - General purpose interface bus.

  Digital instrumentation communication interface.

• Hart protocol - Addressable remote transducer protocol.

  Remote devices communication system.

• Hart modem - Addressable remote transducer interface.

  Remote devices communication transducer.

• LXI - Local area network extension for instruments.

  Digital instrumentation network.

• M-Bus - Meter bus.

  Power programmable devices network.

• Profibus PA.

  Profibus for process automation plants.

For instruments data transfer between digital imaging devices, please see the « computer vision systems networks » rubric below  .

A « virtual serial port » is a program or a driver which emulates a serial COM port and which redirects the data towards a terminal using another communication technology. This technique is very useful when a software can only communicate with a remote device by using RS232 line, and when the distance is very large for instance. In this case, installing « virtual port over IP » will allow easily a remote and stable connection between the both devices.

• Definition.

  What is it about ? What about the conditions to use this technique ?

• Operating principles.

  Virtual serial link Ethernet based synthetic architecture.

• Virtual client port.

  Setting and operating a client over Ethernet.

• Virtual ports server.

  Setting and operating a server over IP.

• MS windows client drivers.

  Free available driver list.

• Linux virtual clients command.

  Presentation of a very powerfull free and open source solution.

• Virtual clients in association with virtual machines.

  How operating a virtual client in a virtual computer.

These high performing networks are specialized in image acquisition devices networks and in image transfer, answering two main constraints imposed by image processing applications which are a large data flow in association with a short response time. They are also used as standard to interface easily the devices from many different device manufacturers, leading in systems which are rather independent from hardware.

• Cameralink.

  Specifications for digital image acquisition.

• IEEE 1394 / DCAM / FIrewire.

  Digital video data transfer protocol.

• Gige Vision.

  High performance standard network system for image data transfer.

These field networks operate at the lowest level in an automated factory. They allow to communicate with the sensors and the actuators ( especially with the devices delivering boolean states ) while they reduce the costs of cabling. Some of these networks allow to manage the smart sensors and the smart actuators, by notably providing adjustment and diagnostic functions in the manner of IO link for instance.

• AS-I - Actuator sensor interface.

  Low cost master /slave architecture device network.

• DeviceNet.

  Lowest level communication for field devices in the CIP family.

• InterBus.

  Sensor and actuator deterministic network supporting hot plugging.

• IO-link - Input output link.

  Low level standard communication interface.

• P-net - Process network.

  Standard process dedicated field bus.

• Profibus DP - Profibus for decentralized peripheral.

  The base of the Siemens networks.

• Profibus IO.

  Profinet for input and output.

Some applications in industrial automation benefit by evolving wireless communications, in particular by managing remote devices which operate in dangerous areas or which provide a difficult access. The radio transmissions technologies ant the Wifi technologies seems the most popular and the most affordable wireless technologies used for industrial applications.

• The « Radio-communication » rubric presents some basic resources in radio frequency and wireless communication systems, some knowledge about the micro-waves spectrum, the modulation, standards and more.
• The « Wifi » rubric presents some well written tutorials about the 802.11 technologies.
• As for the « Wireless software tools » chapter introduces to useful open source software helping you to manage, to scan, to analyse and to diagnose wireless networks through various protocols.
• The « Alternative wireless technologies » section collects resources on wireless networking systems not wide spread in the industry universe yet. Such systems are bluetooth networks, wireless local loops, Li-Fi, infrared modulation, Wimax, wireless USB or Zigbee for instance, without any mention of IOT networks yet.
• The last chapter lists a few wireless associations and organizations, where pieces of technical information could eventually be found.

Networks or widespread communication technologies are sometimes used to give a solution to some industrial applications. We can talk about USB, for instance.