nged. You can check the current page or check for previous versions at the Internet Archive. Yahoo! is not affiliated with the authors of this page or responsible for its content.
Introduction THE
F
OUNDATION fieldbus
PRIMER
Prepared
by
fieldbus inc.
Revision 1.1
Released June 24, 2001 2001 Fieldbus Inc. All rights Reserved
fi







Prolog
Fieldbus Inc. has been involved with F
OUNDATION
fieldbus and its precedent
technologies since 1993. Since 1996 we have worked with clients worldwide in
developing, and registering as interoperable, F
OUNDATION
fieldbus devices. Fieldbus
Inc. is a total solution supplier, capable of providing all required software, hardware,
tools, engineering and project management to assure fast, economical development
programs.
As a result of years of experience, and discussions with many fine clients, we have
prepared this introductory manual to help those new to the field gain a basic
understanding of fieldbus. We sincerely hope our readers find this primer useful, and we
wish you success in mastering this revolutionary new technology.
Fieldbus Inc.
9390 Research Boulevard
Suite I-350
Austin, Texas 78759
Tel: 512 794-1011
Fax: 512 794-3904
www.fieldbusinc.com CONTENTS
THE FOUNDATION FIELDBUS PRIMER........................................................................................... 1
PREFACE................................................................................................................................................... 1
I
NTRODUCTION
............................................................................................................................................ 1
B
ACKGROUND
............................................................................................................................................. 2
FIELDBUS OVERVIEW ............................................................................................................................. 3
Physical Layer ........................................................................................................................................ 4
Communications Capability.................................................................................................................... 6
Function Block Application .................................................................................................................... 7
A S
YSTEMS
P
ERSPECTIVE
............................................................................................................................ 9
Continuous Control Process ................................................................................................................. 10
a)
Temperature Device Failure ......................................................................................................................12
b)
Flow Device Failure ..................................................................................................................................13
c)
Maintenance Concepts ..............................................................................................................................14
Discrete Control Example..................................................................................................................... 15
D
EVICE
D
ESCRIPTIONS
............................................................................................................................... 17
a)
DD Example..............................................................................................................................................17
b)
Menus and Methods ..................................................................................................................................18
c)
Device Programs .......................................................................................................................................18
Configuration........................................................................................................................................ 18
V
IEWPOINT FROM THE
C
ONSOLE
................................................................................................................ 20
d)
Access Privileges.......................................................................................................................................20
e)
Trends........................................................................................................................................................20
f)
Views ........................................................................................................................................................20
g)
Alarms, Alerts and Events .........................................................................................................................21
h)
Mode .........................................................................................................................................................23
C
OMMUNICATIONS
..................................................................................................................................... 24
H
IGH
S
PEED
E
THERNET
(HSE) .................................................................................................................. 27
a)
What HSE Does ........................................................................................................................................27
b)
H1/HSE Interconnections..........................................................................................................................28
c)
Basic Details of the HSE Specification .....................................................................................................29
d)
Redundancy...............................................................................................................................................30
e)
HSE Summary...........................................................................................................................................31
C
ONCLUSION
............................................................................................................................................. 31
APPENDIX I ............................................................................................................................................... 33
EXCERPTS FROM THE IEC/ISA 1987

DRAFT REPORT.................................................................... 33 2001 Fieldbus Inc. All rights Reserved 2001 Fieldbus Inc. All rights Reserved
1


THE F
OUNDATION fieldbus PRIMER
PREFACE
This primer is written for plant operators,
engineers and managers who have at least a
working understanding of process control and
plant operations, and are looking for an
introduction to the basic principles of
F
OUNDATION
fieldbus. The focus will be on
what the technology does and how such fieldbus
systems behave, using examples to illustrate
overall concepts.
Introduction
There are many digital communication
technologies being promoted as the future
replacement for the venerable 420 mA analog
standard, and most are self-described as fieldbus.
With the exception of F
OUNDATION
fieldbus,
virtually all of these technologies were developed
for non-process environments such as automotive
manufacturing, building automation, or discrete
parts manufacturing, and later adapted to process
control. Generally, they are well suited to the
applications for which they were originally
developed. Some of these technologies are open,
some are proprietary. Most are a combination,
having some open aspects but requiring the use
of proprietary hardware or software components.
All but F
OUNDATION
require a proprietary
application to provide a complete control
solution.
Every communication technology provides a
method for transmitting data between various
devices and a host, and some provide
communications directly between devices. The
various schemes differ in how well they are
optimized for moving data quickly, their
suitability for real-time control, the cost of
hardware implementations, their networking
capability for branches, spurs and long distances,
and for how power is distributed.
Comparisons among fieldbus technologies
typically reduces to comparisons of data rates,
message length, number of devices on a segment,
etc. These are all important communications
issues and each technology represents a
particular set of trade-offs which adapt it to its
original application, and each is rooted in the
technology that was available or in vogue at the
time of its development.
Using a strategy exactly opposite of
F
OUNDATION
fieldbus, these various
communications technologies minimize
dependence on local intelligence in deference to
minimum device cost, and maximize reliance on
a centralized control architecture. Measurement
instruments in such structures communicate to a
central computing system at the request of that
central system. A proprietary control
application, running on the central system
processes the field data and distributes control
signals to other devices back in the field.
Regardless of how open th