Fieldbus Technology and Industrial Automation

Abstract

All automation systems are now based on fieldbuses. The solutions are numerous due to the number of fieldbuses, which are in turn due to the variety ofapplications.This paper traces fieldbus technology from its beginnings, which go back to the first industrial networks in the 1970's. It analyzes the fieldbus requirements, in terms offunctions (or services) and of performance (or quality of service). The three following types of quality of service are studied. transport, timeliness and coherence, according to the different types of traffic to ensure (or to operate). The characteristics of periodic and aperiodic traffic are described. The main international standards (IEC, ISO, CEN) are presented regarding these criteria and the main concepts issued from the OSI model. The architecture of applications and the services of the communication system have a mutual influence. This is an important point for the distribution of the application processes, and will be analyzed in regards to the possible application layer models. The architecture of the communication system itself is also studied in the hopes offinding a single system for all applications. Future developments will be considered, regarding both the end-user needs and the available technologies. And finally, to conclude, we will go back to the title and try to answer the question "Is fieldbus a technology? "

Introduction to Industrial Control Networks

“…These include [3], [13], [7] and [12]. This section will cover the main points in the development of industrial control networks, but the reader is encouraged to refer to the cited texts for a more detailed history.…”

“…At the lowest level, between controllers and instruments, there was a need to reduce the wiring requirements of traditional signalling. This requirement led to the development of protocols that would be termed fieldbus in 1985 [3].…”

“…In almost every situation that requires machinery to be monitored and controlled an industrial control network will be installed in some form. Each industry presents its own set of slightly different but generally similar requirements, which can be broadly grouped into the following domains [3]: discrete manufacturing, process control, building automation, utility distribution, transportation and embedded systems.…”

The use of clustered wireless multihop networks in industrial settings

“…It reduces the number of wires. This was one of the main driving forces behind the development of field bus systems [7], where multiple signals to/from sensors, actuators, field controllers and human interfaces were multiplexed on the same wire instead of using a single wire for each individual signal. Further, motions, vibrations, heat variations and aggressive substances put mechanical and chemical stress on wires which eventually = master = slave = gateway break [8], or even worse, introduce transient and intermittent signal errors [9].…”

Performance and Reliability of Fault-Tolerant Ethernet Networked Control Systems

“…1. A general network hierarchy model (Lian et al, 2001b) A wide variety of network protocols can be used to build an NCS, each suitable for a particular application sector (Thomesse, 2005). However, the use of Ethernet remains a viable and interesting option (Decotignie, 2005).…”