04-01-2011, 03:50 PM
[attachment=7942]
SUBMITTED TO:
Er.Neha Jain
SUBMITTED BY:
Saurabh Varshney / 2007 / E.C / 42
PREFACE
Engineering is the science of economy, of conserving the energy, kinetic and potential, provided and stored up by nature for the use of man. It is the business of engineering to utilize this energy to the best advantage, so that there may be the least possible waste of time. Engineering is the professional art of applying science to the optimum conversion of natural resources to the benefit of man. Engineering is associated with creativity and judgment, which is not a theory subject but is an art which can be gained with systematic study, observation and practice. To bridge the gap of theory and practical and to provide a solution for it practical knowledge is very necessary.
In the college circulation we usually get the theoretical knowledge of industries, as how is it work? But how can we prove our theoretical knowledge to increase the productivity or effciency of the industry? To make the learning of engineering more fruitful, we the students of Subharti Institute Of Technology & Engineering,Meerut present a seminar on a technology topic as per specified in the syllabus of Gautum Budh Technical University (GBTU) of B.Tech. final year. This seminar also helps in increasing the understandibility and knowledge about the technology, we present. Succeeding chapters give details about Cloud Computing, a future computing based on internet, together with its deployment models, service layers, benefits, limitations and the top five vendors of it.
CONTENTS
• FIELDBUS INTRODUCTION.
• FIELDBUS AND IEC61158 STANDARD.
• ADVANTAGES OF FIELDBUS.
• FOUNDATION FIELDBUS.
• WHO IS THE FIELDBUS FOUNDATION.
• FOUNDATION FIELDBUS TECHNOLOGY.
Physical Layer (31.25 kbit/s)
• 31.25 kbit/s Fieldbus Signaling
• 31.25 kbit/s Fieldbus Wiring . .
• HSE.
COMMUNICATION STACK
• DLL
• FAS
• FMS
USER APPLICATION BLOCKS.
• FIELDBUS DEVICE FUNCTION
• SYSTEM MANAGEMENT
• SYSTEM CONFIGURATION
• CONCLUSION
FIELDBUS
INTRODUCTION
Fieldbus is a generic-term which describes a new digital communications network which will be used in industry to replace the existing 4 - 20mA analog signal. The network is a digital, bi-directional, multidrop, serial-bus, communications network used to page link isolated field devices, such as controllers, transducers, actuators and sensors. So Fieldbus is a digital communication bus line connecting the field instruments with the control system components.
A field instrument is an instrument attached to a process, e.g.: measurement devices, valves, motor starters and alarm switches .A field instrument to be attached to a fieldbus must be equipped with some intelligence for the bus communication.
A bus is a number of wires for the transfer of digital signals. A fieldbus consists of two wires. The digital signal can be transfered as a voltage difference between the wires – or as a current value.The bus can also be an optical fiber.
Without fieldbus, each field instrument has to be connected to the I/O of the control system, two wires for each instrument.
FIELDBUS AND IEC61158 STANDARD
International standardization organizations have worked for many years in order to get an agreement on a common fieldbus standard. But it seems that it is still a long way to go to get something comparable to the old 4 – 20 mA standard. Among the existing fieldbuses some are better in one system, some other in another system.
In year 2000 it came a document, the IEC 61158 standard, which includes 8 different fieldbuses in the same standard.
The 8 fieldbuses included in this standard are:
• ControlNet
• FF – H1 (Foundation Fieldbus)
• FF – HSE (Foundation Fieldbus)
• Interbus
• P-Net
• PROFIBUS
• SwiftNet
• WorldFip
ADVANTAGES OF FIELDBUS
The fieldbus has a number of advantages that the end users will benefit from.The major advantage of the fieldbus, and the one that is most attractive to the end user is its reduction in capital costs. The various advantages are:
• REDUCING CABLING
One of the main features of the fieldbus is its significant reduction in wiring. Each process cell requires only one wire to be run to the main cable, with a varying number of cells available. The cost of installing field equipment in a fieldbus system is thus significantly reduced. Installation costs are further reduced due to the fact that the fieldbus it is a multi-drop rather than point-to-point system and the multidrop network can offer a 5:1 reduction in field wiring expense.
• HARDWARE REDUCTION
Since all Digital/Analogue or Analogue/Digital transformations have to be done in the instruments, we will also see that fieldbus systems have less hardware components. So, even though a fieldbus instrument usually is more expensive than a traditional one, the overall hardware cost may be lower.
• SIMPLER CONFIGURATION
Less components and less cables mean a system that can easier be configured. Fieldbus systems also have special configuration and documentation tools that will help further.
• SIMPLR MAINTENANCE
The fact that the fieldbus system is less complex than conventional bus systems implies that there will be less overall need for maintenance. With the fieldbus system, it is possible for the operators to easily see all of the devices included in the system and to also easily interpret the interaction between the individual devices. This will make discovering the source of any problems and carrying out maintenance much simpler.
• RELIABILITY
The simplification of systems means that the long term reliability of the bus system is increased.
• FLEXIBILITY
Fieldbus allows the user increased flexibility in the design of the bus system. Some algorithms and control procedures that with conventional bus systems must be contained in control programs can now reside in the individual field devices, reducing the overall size of the main control system. This reduces the overall systems cost and makes future expansion a simpler prospect.
