PROFIBus PROTOCOL
Technology Overview
Communication in automation is becoming
increasingly direct, horizontally at field level as well as vertically
through all hierarchy levels. Depending on the application and price,
graduated and matched industrial communication systems offer the ideal
preconditions for transparent networking in all areas and levels of the
automation process. Profibus offers such a graduated system with the
Ethernet-based PROFInet, the fieldbus PROFIBUS and other systems like
the sensor/actuator bus AS-Interface
At sensor/actuator level signals of binary
sensors and actuators are transmitted via a sensor/actuator bus. At this
level a particularly simple, low-cost installation, through which data
and 24-volt power supply can be transmitted using a common medium, is an
important requirement. AS-Interface is a suitable bus system for this
type of application.
At field level the distributed peripherals,
such as I/O modules, measurement transducers, drive units, valves and
operator terminals communicate with the automation systems via an
efficient, real-time communication system. The transmission of process
data is implemented cyclically, while alarms, parameters and diagnostic
data also have to be transmitted acyclically if necessary. PROFIBUS
meets these requirements and offers a transparent solution for
manufacturing as well as for process automation.
At cell level the programmable controllers
such as PLC and IPC communicate with each other. The information flow
requires large data packets and a large number of powerful communication
functions. Smooth integration into company-wide communication systems,
such as Intranet and Internet via TCP/IP and Ethernet are important
requirements.
The IT revolution in automation technology is
opening up new savings potentials in the optimisation of systems
processes and makes an important contribution towards improved use of
resources. Industrial communication systems have assumed a key function
in this respect.
A Detailed Typical Profibus System
PROFIBUS is a vendor-independent, open field bus
standard for a wide range of applications in manufacturing and process
automation. Vendor-independence and openness are ensured by the
international standards EN 50170, EN 50254 and IEC 61158.
PROFIBUS allows communication between devices of
different manufacturers without any special interface adjustment.
PROFIBUS can be used for both high-speed time critical applications and
complex communication tasks. Through its continuing further technical
developments, PROFIBUS is still the industrial communication system
prepared for the future.
PROFIBUS offers functionally graduated communication
protocols (Communication Profiles): DP and FMS. Depending on the
application, the transmission technologies (Physical Profiles)
RS-485, IEC 1158-2 or fiber optics are available. In the course of
further technical development, the PROFIBUS User Organisation is
currently working on the implementation of universal concepts for
vertical integration on the basis of Ethernet TCP/IP. Application
Profiles define the options of protocol and transmission technology
required in the respective application area for the individual device
types. These profiles also define vendor-independent device behavior.
PROFIBUS defines the technical characteristics of a
serial field bus system with which distributed digital programmable
controllers can be networked, from field level to cell level. PROFIBUS
is a multi-master system and thus allows the joint operation of several
automation, engineering or visualisation systems with their distributed
peripherals on one bus.
See some Smar installations and applications:
Our Profibus products:
http://www.smar.com/products/technology.asp#profibus
For more information, visit the PROFIBus site at:
http://www.profibus.org