What is field bus

<Int> <Ind> <Rev>

Technical
Information Fieldbus Technical Information

TI 38K03A01-01E

Yokogawa Electric Corporation TI 38K03A01-01E
2-9-32, Nakacho, Musashino-shi, Tokyo, 180-8750 Japan ©Copyright Mar. 1998
Tel.: 81-422-52-5634 Fax.: 81-422-52-9802 3rd Edition Sep. 2002

<Toc> <Ind> <Rev> i

Introduction
Fieldbus is an innovative technology for creating field information networks, and is
attracting much interest among users and manufacturers of process control systems.
This manual describes how users can introduce Fieldbus into their process control sys-
tems, and also describes Yokogawa’s Fieldbus solutions and Yokogawa’s Plant Resource
Manager (PRM) software package for managing plant assets in the field network era.

Structure of This Manual
This manual gives an overview of Yokogawa’s Fieldbus Solutions, and explains the ben-
efits of adopting them. For the detail specifications for ordering, refer to the relevant Gen-
eral Specifications. For engineering, installation, operation, and maintenance of the
Fieldbus system and products described in this manual, refer to the relevant Instruction
Manuals.
This manual consists of three parts. Part A outlines Fieldbus prescribed by the Fieldbus
Foundation and Yokogawa’s Fieldbus-ready products, Part B explains Fieldbus engineer-
ing, installation, operation, and maintenance, and Part C outlines the Plant Resource
Manager (PRM) software developed by Yokogawa.

Part A consists of four sections. An overview of the functions and progress of international
standardization of Fieldbus is given in Section A1, the features of Fieldbus in Section A2,
Fieldbus-ready field devices in Section A3, and Yokogawa’s Fieldbus-ready systems in
Section A4.

Part B consists of five sections. Managing Fieldbus engineering is described in Section B1,
design considerations in Section B2, construction considerations in Section B3, startup
considerations in Section B4, and maintenance considerations in Section B5.

Part C consists of four sections. An overview and glossary of Plant Resource Manager
(PRM) are described in Section C1, the system configuration in Section C2, an overview of
functions in Section C3, and the interface to the computerized maintenance management
system in Section C4.

Media No. TI 38K03A01-01E (MO) 3rd Edition : Sep. 2002 (YK) TI 38K03A01-01E Sep.01,2002-00
All Rights Reserved Copyright © 1998, Yokogawa Electric Corporation

<Toc> <Ind> <Rev> ii
Target Readership for This Manual
This manual is mainly intended for:
• Managers who are planning to purchase a control system, Fieldbus, and Plant
Resource Manager (PRM).
• Instrumentation, electricity, maintenance, and computer engineers who are evaluating
process control systems, Fieldbus, and maintenance management systems for
purchase or who will be in charge of installing these systems.

Trademarks
• CENTUM is a registered trademark of Yokogawa Electric Corporation.
• Ethernet is a registered trademark of Xerox Corporation.
• Microsoft and Windows are registered trademarks or trademarks of Microsoft
Corporation in the United States and/or other countries.
• “FOUNDATION” in “FOUNDATION Fieldbus” is a registered trademark of the Fieldbus
Foundation.
• NI-FBUS Monitor is a registered trademark of National Instruments Corporation.
• HART is a registered trademark of the HART Communication Foundation.
• Oracle is a registered trademark of Oracle Corporation.
• MAXIMO is a registered trademark of MRO Software, Inc.
• Other product and company names may be registered trademarks of their respective
companies (the TM or ® mark is not displayed).

TI 38K03A01-01E Sep.01,2002-00

<Int> <Ind> <Rev> Toc A -1

Fieldbus Technical Information
Part A Overview of Fieldbus and
Yokogawa’s Fieldbus-ready Products
TI 38K03A01-01E 3rd Edition

CONTENTS
A1. Progress of International Standardization of Fieldbus ....................... A1-1
A1.1 What is Fieldbus? ......................................................................................... A1-1
A1.2 Progress of Fieldbus Standardization ......................................................... A1-2
A1.3 Fieldbus Standard Specifications ................................................................ A1-4
A1.4 Yokogawa’s Efforts for Fieldbus Standardization ....................................... A1-5
A2. Features of Fieldbus ............................................................................. A2-1
A2.1 Comparison with Conventional Communication ........................................ A2-2
A2.2 Reduced Wiring Cost .................................................................................... A2-4
A2.3 Improved Transmission Accuracy ............................................................... A2-6
A2.4 Enhanced Data Transmission ...................................................................... A2-8
A2.5 Distributed Functions ................................................................................... A2-9
A2.6 Interoperability ............................................................................................ A2-10
A3. Fieldbus-ready Field Devices ............................................................... A3-1
A3.1 Changes in Transmitters .............................................................................. A3-3
A3.1.1 Accuracy Improvement due to Digitalization .................................... A3-4
A3.1.2 Multi-sensing Function Equipment .................................................. A3-6
A3.1.3 Multifunction Equipment ................................................................. A3-7
A3.2 Actuator ......................................................................................................... A3-8
A3.3 Using Self-diagnostics Function................................................................ A3-10
A3.4 Yokogawa’s Fieldbus-ready Field Devices Line-up .................................. A3-11
A4. Yokogawa’s Fieldbus-ready Systems .................................................. A4-1
A4.1 Fieldbus Support in Yokogawa’s CENTUM Control Systems ..................... A4-1
A4.1.1 Fieldbus Support in FCS for FIO of CENTUM CS 3000 ................... A4-2
A4.1.2 Fieldbus Support in FCS for RIO and Compact FCS of
CENTUM CS 3000 ......................................................................... A4-4
A4.1.3 Fieldbus Support in CENTUM CS 1000 .......................................... A4-6
A4.1.4 Fieldbus Support in CENTUM CS ................................................... A4-8
A4.2 Connection of FF Devices from Other Vendors to
Yokogawa’s CENTUM Control Systems .................................................... A4-10

TI 38K03A01-01E Sep.01,2002-00

<A1. Progress of International Standardization of Fieldbus> A1-1

A1. Progress of International
Standardization of Fieldbus
This section describes what is Fieldbus, the progress of standardization of Fieldbus,
Fieldbus standard specifications, and Yokogawa’s efforts toward standardization of
Fieldbus.

A1.1 What is Fieldbus?
The Fieldbus Foundation gives the following definition: “Fieldbus is a digital, two-way, multi-
drop communication link among intelligent measurement and control devices.” Fieldbus is
gradually replacing 4 to 20 mA standard instrumentation signals used to transfer
measurement and control data between control room and plant floor. It is one of several
local area networks dedicated for industrial automation.
Modern industries in the 21st century could not survive without information technologies
and networks. From production line to enterprise level, digital communication supports all
economic and social activities with powerful modern technologies. Fieldbus is one such
technology and cannot be separated from others. Fieldbus is at the lowest level in the
hierarchy and exchanges information with higher-level databases.

IEC (International Electrotechnical Commission) prescribes the following seven definitions
standardized by the standard organizations (shown by their trademarks) as international
standards of Fieldbus:
• FOUNDATION Fieldbus and HSE
• ControlNet
• PROFIBUS and PROFInet
• P-NET
• WorldFIP
• INTERBUS
• SwiftNet

FOUNDATION Fieldbus, which is one of the seven definitions, is a standard defined by the
Fieldbus Foundation. Yokogawa, a member of the board of directors of the Fieldbus
Foundation since its inception, has participated closely in developing the Fieldbus
specifications.
Unfortunately, the Fieldbus standards of IEC list the definitions of many standard organiza-
tions. In practice, all major makers and users are now participating in the Fieldbus Founda-
tion, and many products based on the FOUNDATION Fieldbus specifications are devel-
oped and marketed.
Yokogawa considers that FOUNDATION Fieldbus will be used as widely as the fieldbus for
process control systems in industry. Yokogawa’s CENTUM CS 3000, CENTUM CS 1000,
and CENTUM CS support FOUNDATION Fieldbus.
FOUNDATION Fieldbus H1 (Low Speed Voltage Mode) is called FOUNDATION
Fieldbus, Fieldbus, H1 Fieldbus, FF, or FF-H1 in this manual.

The sophisticated communication functions of Fieldbus allow distributed control via
Fieldbus devices and optimal control by interfacing with a field control station (FCS).

TI 38K03A01-01E Sep.01,2002-00


A1.2 Progress of Fieldbus Standardization
The international standards of Fieldbus have been unified by IEC/TC65/SC65C WG6
(International Electrotechnical Commission/Technical Committee 65/Sub-Committee 65C/
Working Group 6), ISA (The International Society for Measurement & Control) SP50
Committee (which defined 4 to 20 mA analog signals as the standard electronic
instrumentation signal), and the Fieldbus Foundation.
Recently, the Fieldbus Foundation, a private organization formed to promote Fieldbus, is
supporting the international unification of Fieldbus standards. Yokogawa, a member of the
board of directors of the Fieldbus Foundation since its inception, is also promoting
FOUNDATION Fieldbus worldwide.

Recognition as a Standardization Work Item
In 1984, the standardization concept for the next-generation digital communication protocol
for field devices was first proposed to the IEC, which is to replace the 4 to 20 mA analog
transmission. In 1985, IEC/TC65/SC65C recognized the digital communication protocol as
a new standardization work item and named it Fieldbus. IEC/TC65/SC65C WG6, and the
ISA SP50 Committee, which had already commenced discussions on Fieldbus standard-
ization, consented to jointly standardize Fieldbus.

Establishment of the Fieldbus Foundation
The standardization of Fieldbus will have a great effect on industry. Many views were
presented at the ISA SP50 Committee, delaying the standardization of Fieldbus.
To make up for lost time and promote the production of Fieldbus, ISP (Interoperable Sys-
tems Project) was organized by Yokogawa, Fisher Control, Rosemount, and Siemens in
August 1992. In February 1993, ISP became ISP Association.
In March 1993, WorldFIP (Factory Instrumentation Protocol) was jointly created by
Honeywell, A-B (Allen-Bradley), CEGELEC, Telemechanique, and several other
companies.
A consensus was then obtained amongst customers that Fieldbus should conform to the
internationally unified standard. In September 1994, in accordance with this decision, the
ISP Association and WorldFIP North America were combined to form the Fieldbus Founda-
tion.

TI 38K03A01-01E Sep.01,2002-00

Process of Standardization
IEC/TC65/SC65C WG6 and the ISA SP50 Committee started Fieldbus standardization. By
establishing the Fieldbus Foundation, a structure has been built to develop internationally
unified instrumentation specifications.
The process of Fieldbus standardization is shown below.

WorldFIP
North
America

ISA
SP50
Committee The Fieldbus
ISP Foundation
FF-H1 standard is
defined and published.

IEC

1984 1985 1990 1992.8 1993.3 1994.9 1996.8
• 1984
The standardization concept of digital communication protocol for field devices was proposed to IEC.

• 1985
In IEC/TC65/SC65C, the new standardization work item was recognized and named Fieldbus.

• 1990
The ISA SP50 Committee and IEC/TC65/SC65C/WG6 decided to collaborate on Fieldbus standardization.

• August, 1992
ISP was organized.

• March, 1993
WorldFIP was established.

• September, 1994
The ISP Association and WorldFIP North America were combined into The Fieldbus Foundation.
Since then, The Fieldbus Foundation has developed the internationally unified instrumentation specifications.
The Fieldbus standardization structure is configured by IEC, ISA, and The Fieldbus Foundation.

• August, 1996
Fieldbus Foundation defined and published FOUNDATION Fieldbus H1 standard (low speed voltage mode).

A010201E.EPS

Figure Process of Fieldbus Standardization

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A1.3 Fieldbus Standard Specifications
There are two kinds of Fieldbus physical layer specifications standardized by IEC61158-2
and ISA S50.02: low-speed and high-speed Fieldbus specifications. But the high-speed
Fieldbus specification is not adopted and High Speed Ethernet (HSE) specification is
added as additional type.

IEC/ISA Standard Specifications
The low-speed and high-speed Fieldbus specifications are standardized as shown in the
tables below.
Table Fieldbus Specifications (Standard)
Low-Speed Fieldbus High-speed Fieldbus High-speed Fieldbus
Item
FF-H1 FF-H2 FF-HSE (High Speed Ethernet)
Subsystem integration
Positioning Field device integration Subsystem integration Data Server integration
1.0 Mbps (in 1 Mbps mode or
Transmission Speed 31.25 kbps high-speed current mode) 100 Mbps
2.5 Mbps (in 2.5 Mbps mode)
Max. 32 devices/segment Number of connectable devices
Number of Connectable
Max. 32 devices/segment (Using repeaters increase the depend on the subsystem
devices
number of connectable devices.) integrated by FF-HSE.
• Twisted pair cable (shielded) • Twisted pair cable (shielded)
Cable • Twisted pair cable (shielded)
• Optical Fiber • Optical Fiber
Power supply to
Enabled Enabled No
connected devices
Intrinsic safety Enabled Enabled No
Redundancy No (*1) Enabled Enabled

Example of connected Transmitter, control valve, Multicomponent analyzer, Multicomponent analyzer,
devices field multiplexer, etc. PLC, remote I/O, etc. PLC, remote I/O, etc.
A010301E.EPS

*1: Yokogawa has developed dual-redundant configuration of ALF111 Fieldbus Communication Module for FF-H1.

Table Type of Low-speed Fieldbus Cables and Transmissible Length
Max. length of cable
Type of cable Cable specifications (reference value)
Type A: Individually-shielded twisted pair cable #18AWG (0.82 mm2) 1,900 m
2
Type B: Overall-shielded twisted pair cable #22AWG (0.32 mm ) 1,200 m
2
Type C: Unshielded twisted pair cable #26AWG (0.13 mm ) 400 m
Type D: Overall-shielded non-twisted cable #16AWG (1.25 mm2) 200 m
A0130302E.EPS

Note: Yokogawa recommends the use of Type A.
Usage of Types B and D is restricted.
Yokogawa does not recommend the use of Type C.

SEE ALSO
For the cable specifications, refer to Section B2 of Part B.

TI 38K03A01-01E Sep.01,2002-00


A1.4 Yokogawa’s Efforts for Fieldbus Standardization
Yokogawa, a member of the board of directors of the Fieldbus Foundation, has played a
leading role in the international standardization of Fieldbus standards.

Services for Fieldbus Support Devices
Yokogawa has worked hard to promote Fieldbus, and provided the following services to add
value for customers:

Product Development
Yokogawa has developed and provided a variety of products that support Fieldbus, ranging
from various field devices to an integrated production control system, CENTUM CS 3000.

Development of Field Device Management and Diagnostics Packages
Yokogawa has developed and provided field device management and diagnostics pack-
ages which support enhanced field information.

TI 38K03A01-01E Sep.01,2002-00

<A2. Features of Fieldbus> A2-1

A2. Features of Fieldbus
Fieldbus is a bidirectional digital communication protocol for field devices. Fieldbus
technology drastically changes process control systems and is gradually replacing
the standard 4 to 20 mA analog transmission that most current field devices employ.
Fieldbus has the following features:
• Because multiple devices can be connected, and multivariables can be trans-
mitted on a single cable, thus reducing the number of cables, wiring costs are
reduced.
• A digital transmission protocol ensures accurate information processing and
hence strict quality control.
• Multiplex communications allow other information as well as process variables
(PVs) and manipulated variables (MVs) to be transmitted from field devices.
• Communication between field devices allows truly distributed control.
• Interoperability enables devices from different manufacturers to be combined.
• A broad choice of devices from any manufacturer permits flexible system
construction.
• Instrumentation systems, electrical devices, FAs, BAs, OAs, and analyzers can
be integrated.
• Some adjustments and inspections of field devices can be performed from the
control room.

The following sections explain the advantages of Fieldbus and the effect of Fieldbus
on process control systems.

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A2.1 Comparison with Conventional Communication
The Fieldbus communication protocol is superior to analog transmissions and hybrid
communications in information accuracy, transmission speed, and transmission amount. It
also offers superiority to those transmissions and communications in functionality, including
the ability to communicate between connected devices and to communicate bidirectionally.

Analog Transmission
An analog transmission is an information transmission technique using analog signals with
a direct current of 4 to 20 mA. The topology, which is a one-to-one system, allows only one
field device to be connected to a single cable. The transmission direction is one-way.
Therefore, two different cables must be provided: one to acquire information from the field
device, and the other to transmit control signals to the field device.

Hybrid Communication
A hybrid communication is a communication technique in which field device information is
superimposed as digital signals on the conventional 4 to 20 mA analog signal. In addition to
analog transmission capabilities, it is possible to remotely set up the field device range and
zero-point adjustment. Also, maintenance information such as self-diagnostics of the field
device can be obtained using a dedicated terminal.
Hybrid communication protocols were developed independently by each manufacturer, and
so devices from different manufacturers cannot communicate with each other. With the
Yokogawa BRAIN system or the hybrid communication systems of other manufacturers, the
self-diagnostics information cannot be exchanged between field devices from different
manufacturers. A hybrid communication mainly supports 4 to 20 mA analog transmission,
though it also allows digital data communication. The digital data communication speed
through the hybrid communication is slower than that through the Fieldbus communication.

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Fieldbus Communication
The Fieldbus communication protocol, which is different from analog transmissions or
hybrid communications, supports a perfect digital signal communication system. In addi-
tion, the Fieldbus communication supports bidirectional communication, thus allowing more
types and a larger amount of data to be transmitted in comparison to analog transmission
and hybrid communication.
This communication removes the restriction which allows only one field device to be con-
nected to a single cable in an analog transmission system. Multiple field devices can be
connected to a single Fieldbus cable. Also, since this communication is internationally
standardized, interoperability of field devices is guaranteed.
Fieldbus solves the problems of hybrid communications, such as slow digital transmission
speeds and lack of interoperability.
A comparison between the conventional 4 to 20 mA analog transmission, hybrid communi-
cation, and Fieldbus communication protocols is shown below.
Table Comparison of Communication Protocols
Fieldbus Hybrid Analog
Topology Multi-drop One-to-one One-to-one
4 to 20 mA DC
Transmission analog signal 4 to 20 mA DC
Digital signal analog signal
method +
digital signal
One-way
Transmission (analog signal),
Bidirectional One-way
direction bidirectional
(digital signal)
Partially multiplex
Type of signal Multiplex signal Single signal
signal
Differs depending
Standard Standardized in 1996. Standardized
on manufacturers
A020101E.EPS

TI 38K03A01-01E Sep.01,2002-00


A2.2 Reduced Wiring Cost
The introduction of Fieldbus reduces wiring cost by means of multi-drop connections and
multivariable transmission.

Multi-drop Connections
Connecting multiple field devices to a single cable is known as multi-drop connections, and
the reduction in the number of cables has many advantages. An example of multi-drop
connections is shown below.

Fieldbus Multi-drop connection

To the system

Field device Field device
A020201E.EPS

Figure Multi-drop Connections

In a conventional analog transmission system, only one field device can be connected to a
single cable that leads to a system. Multi-drop connections connect multiple field devices to
a single cable, and so allow additional field devices to be connected to a cable which has
already been laid.
In the past, it was costly to connect multiple field devices. Using a Fieldbus communication
system, it is possible to connect a large number of field devices to the Fieldbus because of
low wiring cost by multi-drop connections. This expands the scale of process control
systems and promotes a higher level of plant automation.

TI 38K03A01-01E Sep.01,2002-00

Multivariable Detection and Transmission
Multivariable means multiple measured variables, and multivariable detection means that
one field device can detect multiple measured variables, which is also called multi-sensing.
A conventional analog transmission system requires one cable for each measured variable.
Fieldbus supports multivariable transmission. Therefore, a field device can transmit all
measured variables detected by the field device via a single cable.
The difference in wiring a control valve between analog and Fieldbus communication
systems is shown below.

Conventional Analog Transmission System Fieldbus Communication System

Fieldbus
Positioner control signal
Lower limit signal Positioner control signal
Lower limit signal
Valve opening signal Valve opening signal
Upper limit signal Upper limit signal

Positioner Positioner

Control valve Control valve

Number of cables Number of cables
• Positioner control signal : 1 pair • Fieldbus : 1 pair
• Valve opening signal : 1 pair
• Upper/lower limit signal : 2 pairs
Total : 4 pairs

A020202E.EPS

Figure Difference in Detection and Transmission between Analog Transmission and Fieldbus
Communication Systems

In the conventional analog transmission system, the control output signal to the positioner
is usually transmitted. In a Fieldbus communication system, multiple pieces of information
such as control signals, limit signals, and valve opening signals can all be detected and
transmitted.
Multivariable detection and transmission can be used for:
• Monitoring the condition of the steam heat tracing of differential pressure transmitters
by ambient temperature information.
• Detecting clogging in impulse lines by static pressure information.
Many other pieces of information will also be used to expand measurement and control
capabilities.

TI 38K03A01-01E Sep.01,2002-00


A2.3 Improved Transmission Accuracy
Fieldbus improves transmission accuracy by eliminating errors that occur during data
transmission in the conventional analog transmission system.

Removing Error Factors
The following three factors cause errors in the conventional analog transmission system.
• D/A conversion in the field device
• Analog signal transmission
• A/D conversion in the system
For example, if data is transmitted from a field device with a microprocessor in the conven-
tional analog transmission system, an error may result during A/D and D/A data conversion.
Fieldbus eliminates transmission errors and conversion errors during data transmission.
The difference in transmission accuracy between the conventional analog transmission
system and the Fieldbus communication system is shown below.

Conventional Analog Transmission System

Error due to data conversion Error due to data conversion

4 to 20 mA analog signal
Sensor µP D/A A/D System

Data transmission direction PVs with transmission errors
Error due to analog signal transmission

Upgrade to Fieldbus

Fieldbus Communication System

Digital signal
Sensor µP Modem Modem System

Data transmission direction PVs without transmission errors

A020301E.EPS

Figure Difference in Transmission Accuracy between Analog Transmission and Fieldbus
Communication Systems

Fieldbus transmits data using digital signals. Signal transmission errors rarely occur in
digital signal transmission, unlike analog signal transmission. In addition, Fieldbus does not
need A/D and D/A conversions because data is always transmitted digitally. Fieldbus
removes these three error factors, improving transmission accuracy.
System reliability also improves as a result of higher transmission accuracy, which allows
stricter quality control and greater production efficiency.

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Making the Most of Field Device Accuracy
Improved data transmission means accurate transmission of data which is detected by field
devices. Especially, digital field devices reduce transmission errors and conversion errors of
digital signals detected by sensors. Therefore, a Fieldbus communication system can take
advantage of the performance of high-accuracy field devices.

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A2.4 Enhanced Data Transmission
In a Fieldbus communication system, many pieces of field information as well as PVs and
MVs can be exchanged between field devices. Fieldbus can transmit many kinds of data
bidirectionally, so the system offers more advanced functionality than a conventional
analog transmission system.

Various Types of Data Transmission
Fieldbus can transmit various types of data.
The conventional analog transmission system cannot transmit data other than PVs and
MVs. Although hybrid communication, an analog communication protocol with a digital data
transmission function, allows various types of data transmission, the hybrid communication
protocol has the following problems:
• The transmission speed is slow.
• Only one-to-one communication between a system and a field device is possible.

Fieldbus solves the problems associated with hybrid communication.
• The transmission speed is fast.
• Multiple pairs of devices can simultaneously communicate among a system and field
devices, and between field devices.

Transmission of various types of data allows the following advanced functionalities.
• Since past maintenance information can be easily acquired, maintenance efficiency
improves.
• Device management such as field device master file creation can be automated.

Bidirectional Communication
Fieldbus transmits multiplexed digital information. This enables the system to perform
bidirectional communication, which is not possible with the conventional analog transmis-
sion system.

Data Exchange between Field Devices
Distribution of control to field devices is made possible by exchanging data between them.

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A2.5 Distributed Functions
The use of Fieldbus implements integrated control over the entire plant and autonomous
distributed control.

Installing Advanced Functions in Field Devices
Fieldbus allows the exchange of field information used for control in addition to PVs and
MVs.
Field devices with a calculation function and other functions can thus be adjusted from a
system. Although some functions such as correction computation have been installed in
current field devices, various functions that use more information are expected to be
included in future field devices.
By doing this, a field device such as a positioner will be able to field-adjust valve control
characteristics.

Distributing Functions to the Field
Depending on the requirements of the processes to be controlled, field devices are
equipped with advanced functions that provide some control functionality that used to be
provided by a system.
Distribution of control to field devices will change system functions.

Functions of Field Devices and System
By increasing the functionality of field devices and distributing control functions, the func-
tions will vary between field devices and system.
For example, the user can install the PID function for each control object in a field device or
a system.
If the relation between loops is tight and they cover a wide range in a large-scale plant, the
PID function will be generally installed in the system. Conversely, if the loops are relatively
independent in a small-scale plant, the PID function may be installed in a field device.
In an oil refinery or a petrochemical, for example, the PID function is closely related to
complex control, advanced control, optimized control, and integrated control over the entire
plant. Therefore, excluding some independent control loops, the PID function will be in-
stalled in the system.

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A2.6 Interoperability
Conventional hybrid communications can transmit digital signals, but information exchange
between devices of different manufacturers is difficult because each device uses its
manufacturer’s protocol.
In Fieldbus communication, international standardization of the protocol ensures the
Interoperability between FF devices including FF interface card in host system. FF devices
allow digital data to be exchanged between devices from different manufacturers. There-
fore, the freedom to configure the process control system increases since there is no need
to choose one device manufacturer.

The Fieldbus Foundation prescribes the interoperability test procedure called
Interoperability Test (IT) to ensure the Interoperability for the FF devices, and the FF de-
vices that passed the IT are registered to the Foundation, and published on the Fieldbus
Foundation’s web site (http://www.fieldbus.org/). Yokogawa registered EJA series transmit-
ter as the world’s first vendor.
Fieldbus Foundation started the Host Interoperability Support Test (HIST) for host com-
puter in September 2000. On September 14, 2000, Yokogawa’s CENTUM series were
certified as the system able to execute the Host Interoperability Support Test (HIST),
becoming the world’s first vendor to carry out the HIST. The HIST is to prove the
interoperability between the host computer and devices. The various devices from different
manufacturers has been tested by the CENTUM series with the HIST procedure, and the
interoperability has been proved.

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<A3. Fieldbus-ready Field Devices> A3-1

A3. Fieldbus-ready Field Devices
When Fieldbus is introduced, the type and amount of transmissible information will
drastically increase. Also, bidirectional communication of digital information can
take place between a field device and a system, and between field devices. To make
the most of communication improvements and to satisfy more advanced needs, big
changes are taking place with field devices. This section explains the differences in
field devices when Fieldbus is introduced in a communication system.

Difference between Analog Transmission and Fieldbus Communication
Systems
The Fieldbus communication system transmits information differently from the conventional
analog transmission system. It has the following capabilities:
• A large amount of information can be transmitted.
• There are many types of transmissible information, both control and non-control
information.
• Digital information can be transmitted.
• Bidirectional communication is possible between a field device and a system.
• Bidirectional communication is possible between field devices.
According to those differences, the information handled by field devices (field information)
changes significantly.
The differences between analog transmission and Fieldbus communication systems is
shown below.
Conventional Analog Transmission System Fieldbus Communication System

Computer Control bus
gateway
Control Control valve
station
Sequencer Fieldbus
Controller
gateway
Sequencer Field
junction box
Remote I/O card,
terminal board
4 to 20 mA analog
communication
cable

One variable Multivariable Bidirectional communication
One way Bidirectional is possible between the
control valve and flowmeters.

Flowmeter

Flowmeter Control valve

A030001E.EPS
Figure Difference between Analog Transmission and Fieldbus Communication Systems
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Advanced Functionality of Field Devices
By making the most of Fieldbus communication system features, it is possible to have more
advanced control over the system. As a result, more advanced functionality is required in
field devices.
For example, by transmitting self-diagnostics information from a field device to the system,
with the appropriate timing, the system can control the field device according to its status
and can predict a problem in the field device. Also, by exchanging data (PV, MV, etc.)
between field devices, autonomously distributed control of multiple field devices will be
possible.

Once the main power to the process control systems was changed from air to electricity,
new electric-powered field devices appeared on the market. Similarly, when process
control systems are changing from analog transmission to Fieldbus communication, new
field devices that support Fieldbus communication capabilities are appearing on the mar-
ket.

Field devices are primarily categorized into transmitters and actuators. Fieldbus will bring
about changes in both components. The following sections describe what changes will
occur in transmitters and actuators.

TI 38K03A01-01E Sep.01,2002-00


A3.1 Changes in Transmitters
The Fieldbus communication system can transmit digital information in a single line. There-
fore, the function of a transmitter is changing greatly.
In a conventional analog transmission system, transmitters are primarily designed to
transmit the PV value to be measured to the system. This is because the analog transmis-
sion system performs one-way communication, from a field device to a system, or vice
versa.
By using the Fieldbus communication system, the type and amount of information being
transmitted through a single cable will increase drastically, and will be far greater than that
of a conventional analog transmission system. In addition, bidirectional communication can
be performed between a field device and a system, and between field devices. Since digital
information can be transmitted to field devices without conversion, information will be much
more reliable.

TI 38K03A01-01E Sep.01,2002-00


A3.1.1 Accuracy Improvement due to Digitalization
Since the Fieldbus communication system transmits information digitally, it can transmit the
measured data from a transmitter to the system with minimum error. Many transmitters with
drastically higher accuracy come to market.

Improvement of Transmission Accuracy
A transmitter with the conventional analog transmission handled a PV value as a percent-
age (0 to 100 % relative value) of the measuring range, and transmitted this value to the
system after converting to a 4 to 20 mA analog signal. The system converted the 4 to 20
mA analog signal that was transmitted to the digital signal in engineering unit, and used it.
Errors occur during these signal conversion.

In contrast, a transmitter with the Fieldbus communication handles a PV value in engineer-
ing units and transmits this value, without conversion, to the system as a digital signal. The
system uses the digital signal as it was transmitted. The Fieldbus communication system
does not require signal conversion, thereby eliminating conversion errors that occur during
transmission of measured data.
The Fieldbus communication system provides for higher data transmission accuracy
compared to the analog transmission system.

Using the example of the orifice flowmeter which uses a differential pressure transmitter,
the difference in transmission accuracy between the analog transmission and Fieldbus
communication systems is described below.
In a conventional analog transmission system, the differential pressure generated at the
orifice, proportional to the square of the flow rate, was measured by a differential pressure
transmitter and transmitted to the system after converting to a 4 to 20 mA signal. If the
differential pressure, P at the orifice is 2 kPa when the flow rate is 20 Nm3/h, the output
signal of the differential pressure transmitter will be as shown in the table below. The
analog transmission system generates an error when this output signal is converted to a
digital signal in the system side.
If the differential pressure is converted to a flow rate on the system side, the transmission
error will be changed by the flow rate because this conversion is not linear as shown in
Figure below.
Table Analog Signal Data

Differential
Output Flow rate
pressure
4 mA 0 kPa 0 N m3/h
20 mA 2 kPa 20 N m3/h
A030101E.EPS

Flow rate

Differential
pressure
A030102E.EPS

Figure Relationship between Differential Pressure and Flow Rate

TI 38K03A01-01E Sep.01,2002-00

In contrast, the Fieldbus communication system transmits the flow signal in engineering
units as a digital signal. Therefore, there is no error during transmission. In this example,
the differential pressure generated by the orifice is calculated and converted to a flow rate
by the microprocessor of the differential pressure transmitter. The flow signal in engineering
unit is transmitted to the system as a digital signal without conversion.

Improvement of Transmitter Measuring Accuracy
If the transmission accuracy is improved by the Fieldbus communication, the improvement
of transmitter measuring accuracy will be a factor in improving the accuracy of the entire
process control system. To perform measurements at higher accuracy, field devices that
employ a superior measurement principle will be widely used.
For example, conventional mechanical flow meters and level meters will be replaced by
electric flow meters and level meters that employ digital technology.

Since the Fieldbus communication system transmits the measured data in engineering
units, without dependence on measuring range, a transmitter with a wide measuring range
will show the original measuring performance. The width of the measuring range is one of
the most important factors in determining the quality of transmitters.

TI 38K03A01-01E Sep.01,2002-00


A3.1.2 Multi-sensing Function Equipment
The function used to measure multiple variables with a single transmitter is known as the
multi-sensing function.
In a Fieldbus communication system, it is possible to transmit multiple pieces of information
over a single cable. To make the most of this Fieldbus feature, users will demand transmit-
ters equipped with a multi-sensing function.

In a conventional analog transmission system, a transmission cable with a pair of wires is
required to transmit one measured value. For example, a transmitter that can perform
multiple measurements, such as the Coriolis flowmeter, requires multiple cables to transmit
multiple measurement variables.
The Fieldbus communication system allows the Coriolis flowmeter to transmit multiple
measurement variables via a single cable.

Transmitters that have been used to perform only one measurement are enhanced to
perform the multi-sensing function using the Fieldbus communication system.
For example, the differential pressure transmitter is able to measure process pressure,
ambient temperature, etc., in addition to flow rate, which was the transmitter’s original
function. If a temperature sensor for measuring the process temperature is combined with
this differential pressure transmitter, all flow rate, pressure, and temperature variables
necessary for process control will be measurable by the transmitter alone.

Possible data that will be gained by multi-sensing function for the main transmitters are
shown below.
• Differential pressure flowmeter: Mass flow, volume flow, pressure, temperature
• Magnetic flowmeter: Volume flow, conductivity, temperature
• Vortex flowmeter: Mass flow, volume flow, temperature, pressure
• Coriolis flowmeter: Mass flow, volume flow, density, temperature
• Differential pressure level meter: Liquid level, density and specific gravity, tank
internal pressure, temperature
• Ultrasonic level meter: Liquid level, temperature
• Temperature transmitter: Humidity, ambient temperature, vibration
• pH meter: pH, temperature
• Conductivity meter: Conductivity, temperature

TI 38K03A01-01E Sep.01,2002-00


A3.1.3 Multifunction Equipment
A Fieldbus communication system can transmit other information in addition to the PV
value. To make the most of this feature, the transmitter is expected to calculate the multiple
values and process them into the required information for control.
A transmitter that incorporates multiple functions, such as the calculation function, is known
as a multifunction transmitter. Multifunction transmitters increase for a Fieldbus communi-
cation system.

The main function of transmitters used in a conventional analog transmission system is to
measure a PV value at high-accuracy and transmit it. To do this, additional devices are
used for converting the measured PV value into the information necessary for control.
A multifunction transmitter can calculate the PV value in engineering units required by the
user and transmit it to the system.
If a multifunction transmitter is used in combination with the above multi-sensing function, it
is possible to drastically simplify the process control system.
For example, assume that there is a differential pressure transmitter which can multi-sense
the flow rate, pressure, and temperature. If a calculation function is added to this differential
pressure transmitter, it allows the transmitter to calculate the mass flow rate after tempera-
ture-pressure compensation using the measured flow rate, pressure, and temperature, and
before executing transmission.
To attain the above functions, a conventional analog transmission system would require
three transmitters, one each for flow rate, pressure, and temperature, and an additional
calculator for temperature-pressure compensation. A single multifunction transmitter with
multi-sensing can process all of this.
This will not only drastically reduce the instrumentation cost, but will also improve the
reliability.

TI 38K03A01-01E Sep.01,2002-00


A3.2 Actuator
Fieldbus is expected to offer many possibilities for actuators.
This section explains, using a typical control valve actuator, the changes that are taking
place in actuators.

Control Valve Changes
The progress brought about by Fieldbus communication will drastically change the role of
the control valve.
A control valve with a conventional analog transmission controls a valve using a positioner
according to the MV value transmitted from the system.
On the other hand, a control valve with Fieldbus communication does not only control the
valve to a constant opening, but also returns the valve opening value back, with respect to
the MV value, and outputs limit signals to the system. This will promise more stabilized
control of the system without valve opening meter and limit switches separately.
Also, this valve and its positioner are able to perform valve characteristic modifications,
temperature compensations, etc., which were usually made by the system. This will make it
possible to compensate for valve operation as close to the process state as possible, while
monitoring the valve characteristics.

If this positioner and valve are combined with a flowmeter, the feedback control of a control
valve, which is currently handled by the system, will be handled by only the control valve.
Features of control valves with the Fieldbus communication are summarized next.

TI 38K03A01-01E Sep.01,2002-00

Features of Control Valves with the Fieldbus Communication
• Improvement of valve controllability (detects stroke cycle, open-close time, etc. to
predict clogging, sticking, leakage, etc.)
• Remote monitoring of control valves
• Modification and improvement of valve characteristics
• Stabilized control together with operability and complete closure of valves
• Improved valve stability
• Ease-to-operate adjustment and stabilization of valve characteristics
• Reduction of valve accessories

The following figure shows the compensation curves of valve flow characteristics. By using
the control valve with the Fieldbus communication, the following valve flow characteristics
will be change easily. In addition, it is possible to adopt the customized characteristics.

Intrinsic flow characteristics (from ISA Hand Book of Control Valve)

t
en

oo
er
k op

r
ua
Sq
Quic

r
nea
Li

t
cen
per
ual
Eq
lic
rbo
pe
Hy
Flow rate

Valve opening
A030201E.EPS

Figure Modification of Valve Flow Characteristics

TI 38K03A01-01E Sep.01,2002-00


A3.3 Using Self-diagnostics Function
The Fieldbus communication system can predict a problem in a field device using the self-
diagnostics function.

Integration of Instrumentation and Self-diagnostics Functions
The conventional analog transmission system can handle only one signal on a single
cable. The system handles the PV or MV value and the self-diagnostics information as
completely different data, even if it is information from the same field device.
The Fieldbus communication system can handle multiple signals on a single cable. The
system can handle the PV or MV value and the self-diagnostics information in the same
environment. Instrumentation and self-diagnostics will be performed under the same
environment by integrating work in the field into a single network.
This idea is far different from the conventional one which has separated instrumentation
from self-diagnostics.

Problem Prediction Function
Since Fieldbus handles the measured values in engineering units, it allows the system to
accurately measure slight changes in pressure and temperature, other than the PV value.
This enables the system to detect the symptoms of problems that were difficult to predict.

For example, suppose the system cannot judge whether the self-diagnostics result of a
field device is abnormal or normal. The conventional analog transmission system can
transmit a self-diagnostics result as either abnormal or normal. Therefore, if a result cannot
be judged as being abnormal or normal, the system always handles it as abnormal for
safety. If a minor abnormality is generated in field devices, a number of alarms will be
displayed on the panel in the control room. However, if minor abnormalities in field devices
are handled as normal to reduce alarms in the control room, the symptom of a major
problem may not be detected.

If a self-diagnostics result cannot be judged as abnormal or normal, Fieldbus communica-
tion system can transmit the status information to the system. In addition, Fieldbus com-
munication system will be able to monitor the information which influences measurement
and control, such as clogging, vibration, etc. The use of this information allows the system
to chronologically analyze changes in field devices and predict their problems.
Using the dedicated package software will make the maintenance work easier.

TI 38K03A01-01E Sep.01,2002-00


A3.4 Yokogawa’s Fieldbus-ready Field Devices Line-
up
Differential Pressure/Pressure Transmitter DPharp EJA Series (suffix code
for output: F)
Function Block: Two (2) AI function blocks
One (1) PID function block (option: /LC1)
Link Master function (option: /LC1)
Hazardous area certification for FM, CENELEC, CSA, or JIS is available. FISCO model for
FM or CENELEC intrinsically safe is also available.
(See GS 01C22T02-00E for the detail.)

Vortex Flowmeter YF100 (YEWFLO*E) (suffix code for output: F)
Function Block: One (1) AI function block
(See GS 01F02F04-00E for the detail.)

Magnetic Flowmeter ADMAG AE (with option code /FB)
Function Block: One (1) AI function block
Hazardous area certification for CENELEC ATEX is available.
(See GS 01E07F01-00E for the detail.)

Temperature Transmitter YTA320 (suffix code for output: F)
Function Block: Four (4) AI function blocks
One or two (1 or 2) PID function block(s) (option: /LC1 or /LC2)
Link Master function: with one (1) PID function block (option: /LC1)
with two (2) PID function blocks (option: /LC2)
Hazardous area certification for FM, CENELEC, CSA, SAA, or JIS is available. FISCO
model for CENELEC intrinsically safe is also available.
(See GS 01C50T02-00E for the detail.)

TI 38K03A01-01E Sep.01,2002-00

Advanced Valve Positioner YVP110
Function Block: One (1) AO function block
Two (2) DI function block
One (1) OS (Output Splitter) function block
Signature Function:(option: /BP)
Hazardous area certification for FM, CENELEC, CSA, or JIS is available. FISCO model for
FM or CENELEC intrinsically safe is also available.
(See GS 21B04C01-01E for the detail.)

YVP Management Software <Model: YVP20S>
This software package offers a variety of functions to help users to easily set up and tune
YVP110.
This software needs National Instruments FBUS fieldbus communication interface card.
(See GS 21B04C50-01E for the detail.)

Paperless Digital Recorder DAQSTATION (with option code /CF1)
Function Block: Eight (8) AI function block (1-channel each)
One (1) MAO function block (8-channel)
Link Master function
(See GS 04L01A01-00E for the detail.)

TI 38K03A01-01E Sep.01,2002-00

<A4. Yokogawa’s Fieldbus-ready Systems> A4-1

A4. Yokogawa’s Fieldbus-ready Systems
The control system that uses Fieldbus communication handles more advanced
information than the conventional analog transmission system. Information recep-
tion, display and record management are more important factors in control systems.
This section describes the Yokogawa systems that support Fieldbus.
The “H1 Fieldbus Communication Protocol” and “H1 Fieldbus” indicated in this
section and Part B are the “FOUNDATION Fieldbus H1 (Low Speed Voltage Mode)”
of the Fieldbus Foundation.

A4.1 Fieldbus Support in Yokogawa’s CENTUM
Control Systems
The CENTUM CS 3000 Integrated Production Control System, CENTUM CS 1000 Produc-
tion Control System, and CENTUM CS Integrated Production Control System support
Fieldbus.
This section describes a typical system configuration for each CENTUM Fieldbus system.
These systems are connected to field devices via I/O modules which support 1-5 V DC/4-
20 mA I/Os, thermocouple and resistance temperature detector inputs, digital I/O, and
communication. The Fieldbus Communication Module can also be combined with such
conventional analog I/O modules.

TI 38K03A01-01E Sep.01,2002-00


A4.1.1 Fieldbus Support in FCS for FIO of CENTUM CS 3000
Fieldbus support in FCS for FIO of CENTUM CS 3000 is shown below. FCS for FIO can be
connected via an ALF111 Fieldbus Communication Module installed in a node unit to FF
transmitters and FF valve positioners.

Operation and Ethernet
monitoring function
Engineering function
(system generation) HIS PRM
Fieldbus tools:
• Engineering tool
• Device management
tool
V net

FCS
FCU

ESB bus

EB401 SB401
ALF111 ALF111
(dual (dual
IS barrier or (in service) (stand-by)
redundant) redundant)
lightning arrester
(optional)
H1 fieldbus segment Local Node
Terminator
Terminator
(optional)
Fieldbus
ER bus
power supply unit (optional)

ACB41
EB501
ALF111 ALF111
(dual
IS barrier or (in service) (stand-by)
redundant)
lightning arrester
(optional)
H1 fieldbus segment Remote Node
Terminator
Terminator
(optional)
Fieldbus
power supply unit (optional)

HIS: Human Interface station
PRM: Plant Resource Manager
FCS: Field control station
FCU: Field control unit
SB401: ESB-bus interface (in Local Node)
EB401: ER-bus interface (in Local Node)
EB501: ER-bus interface (in Remote Node)
ALF111: Foundation Fieldbus communication module
ACB41: I/O expansion cabinet for FIO
A040101E.EPS

Figure Fieldbus Support in FCS for FIO of CENTUM CS 3000

TI 38K03A01-01E Sep.01,2002-00

ALF111 Fieldbus Communication Module Specifications
Number of ALF111s per FCS:
Standard FCS control function: Max. 16 (*1) modules (8 pairs for a dual-
redundant configuration) per FCS
Enhanced FCS control function: Max. 32 (*2) modules (16 pairs for a dual-
redundant configuration) per FCS
Number of ALF111 ports: Max. 4 ports per ALF111 (One port is connected
to one segment (*3).)
Number of field devices per segment (*3): Max. 32 units per segment (including an
ALF111 as one unit)
Number of FF faceplate blocks: Max. 250 blocks for Standard FCS (general-
purpose database)
Max. 600 blocks for Enhanced FCS (general-
purpose database)
ALF111 dual-redundant support: Dual-redundant configuration possible with two
adjacent ALF111s in a node
Link active scheduler (LAS) function: Available
Time master function: Available
The number of field devices per segment varies significantly depending on the cable
length, power supply capacity, existence of a barrier, etc. For details, refer to Section B2.2
of Part B.
Other Fieldbus specifications are in accordance with the specifications for the FOUNDA-
TION Fieldbus.
*1: For the standard FCS control function, the maximum number of ALF111s may be two depending on the
database type selected as the FCS database. For details, refer to GS, “Control Function for Standard Field
Control Station (for FIO)” (GS 33Q03K30-31E).
*2: For the enhanced FCS control function, when “remote node expanded” is selected as the database type, the
maximum number of ALF111s is 32. In the other database type, the maximum number of ALF111s is 16. For
details, refer to GS, “Control Function for Enhanced Field Control Station (for FIO)” (GS 33Q03K31-31E).
*3: A segment is an engineering unit consisting of several Fieldbus devices and ALF111 port to be connected to
one H1 Fieldbus.

SEE ALSO
For details of the ALF111 Fieldbus Communication Module, refer to GS 33Q03L60-31E.

TI 38K03A01-01E Sep.01,2002-00


A4.1.2 Fieldbus Support in FCS for RIO and Compact FCS of
CENTUM CS 3000
Fieldbus support in FCS for RIO and Compact FCS of CENTUM CS 3000 is shown below.
FCS for RIO and Compact FCS can be connected via an ACF11 Fieldbus Communication
Module installed in an I/O module nest to FF transmitters and FF valve positioners.

monitoring function
Fieldbus tools:
tool
V net

LFCS SFCS

RIO bus

NIU ACF11

ACF11

Fieldbus
External
power supply
(optional)
Intrinsic safety barrier /
arrester Terminator
(optional)

Coupler
Terminator H1 Fieldbus
(optional)
Coupler
HIS: Human Interface Station
LFCS: Standard FCS
SFCS: Compact FCS Field devices
RIO bus: Remote I/O bus
NIU: Node Interface Unit
ACF11: Fieldbus Communication Module
A040102E.EPS

Figure Fieldbus Support in FCS for RIO and Compact FCS of CENTUM CS 3000

TI 38K03A01-01E Sep.01,2002-00

ACF11 Fieldbus Communication Module Specifications of CENTUM CS
3000
The main specifications of the ACF11 Fieldbus Communication Module of CENTUM CS
3000 are shown below.

For LFCS (FCS for RIO)
Number of ACF11s per FCS: Max. 80 modules per FCS
Number of ACF11s per AMN33 nest: Max. two modules per nest
Number of segments (*1) per ACF11: Max. one segment
ACF11 as one unit)
Fieldbus power supply: Available (supply current: max. 80 mA)

For SFCS (Compact FCS)
ACF11 as one unit)

*1: A segment is an engineering unit consisting of several Fieldbus devices and ACF11 to be connected to one H1
Fieldbus.

SEE ALSO
For details of the ACF11 Fieldbus Communication Module of CENTUM CS 3000, refer to GS 33Q03L50-
31E.

TI 38K03A01-01E Sep.01,2002-00


A4.1.3 Fieldbus Support in CENTUM CS 1000
Fieldbus support in CENTUM CS 1000 is shown below. FCS can be connected via an
ACF11 Fieldbus Communication Module installed in an I/O module nest to FF transmitters
and FF valve positioners.

monitoring function
Fieldbus tools:
tool
VL net

PFCS

ACF11
External
power supply Terminator
(optional)
Intrinsic safety barrier /
arrester
(optional)

Coupler
Terminator H1 Fieldbus
(optional)
Coupler

HIS: Human Interface Station
PFCS: Control Station Field devices
A040103E.EPS

Figure Fieldbus Support in CENTUM CS 1000

TI 38K03A01-01E Sep.01,2002-00

1000
1000 are shown below.
ACF11 as one unit)

Fieldbus.

SEE ALSO
For details of the ACF11 Fieldbus Communication Module of CENTUM CS 1000, refer to GS 33S03L50-
31E.

TI 38K03A01-01E Sep.01,2002-00


A4.1.4 Fieldbus Support in CENTUM CS
Fieldbus support in CENTUM CS is shown below. FCS can be connected via an ACF11
Fieldbus Communication Module installed in an I/O module nest to FF transmitter and FF
valve positioners.

Operation and monitoring function
System generation function Fieldbus tools
PC • Engineering tool
ICS EWS • Device Management tool

Ethernet

ACG
V net

FCS FCU

RIO bus

NIU

ACF11
External
power supply Terminator
(optional)

Intrinsic safety barrier / arrester
(optional)

Coupler
H1 Fieldbus
Terminator
(optional)
Coupler
ICS: Information and Command Station
ACG: Communication Gateway Unit
FCS: Field Control Station
FCU: Field Control Unit Field devices
RIO bus: Remote I/O bus
NIU: Node Interface Unit
A040104E.EPS

Figure Fieldbus Support in CENTUM CS

TI 38K03A01-01E Sep.01,2002-00

are shown below.
ACF11 as one unit)

Fieldbus.

SEE ALSO
For details of the ACF11 Fieldbus Communication Module of CENTUM CS, refer to GS 33G6K40-01E.

TI 38K03A01-01E Sep.01,2002-00


A4.2 Connection of FF Devices from Other Vendors
to Yokogawa’s CENTUM Control Systems
FF devices from other vendors can be connected to CENTUM under the following condi-
tions:

Use devices registered by the Fieldbus Foundation
The Fieldbus Foundation prescribes the interoperability test procedure called
Interoperability Test (IT) to ensure interoperability between the FF devices. The FF devices
that passed the IT are registered to the Foundation, and information about them is pub-
lished on the Fieldbus Foundation’s web site (http://www.fieldbus.org/).
The field devices from other vendors, which are registered to Fieldbus Foundation, can be
connected to CENTUM. Yokogawa recommends to use the IT4.0 (or later version) registra-
tion devices including the Capabilities File and Device Description (DD) File.
For the Fieldbus accessories (e.g. cables, external bus power supply units, barriers, and
arresters), there is no system of registering to the Fieldbus Foundation; these accessories
should be used according to the conditions provided by their vendors.
Yokogawa informs users of field-proven Fieldbus accessories as recommended devices.
Contact Yokogawa sales for the Fieldbus accessories if necessary.

Use devices as instructed
Use devices according to the conditions provided by their vendors. The vendors assume
responsibility for the quality, performance and warranty of their field devices.

Test devices
A user who uses field devices from other vendors is responsible for testing them.
Yokogawa, if required, will provide assessment information on connecting other vendors’
devices to CENTUM, to assist users in device selection.

Yokogawa supports only standard Fieldbus specifications, not manufac-
turer-specific extensions
Yokogawa’s systems support information and functions that meet the standard specifica-
tions prescribed by the Fieldbus Foundation. They may not support another manufacturer’s
proprietary functions.

The Fieldbus standardization facilitates operation and maintenance of field devices from
different manufacturers. Yokogawa can meet a variety of user needs, including startup and
maintenance work on process control systems including products (components) from other
vendors, based on accumulated know-how about devices and their usage.

TI 38K03A01-01E Sep.01,2002-00

<Int> <Ind> <Rev> Toc B -1

Fieldbus Technical Information
Part B Fieldbus Engineering
TI 38K03A01-01E 3rd Edition

CONTENTS
B1. Managing Fieldbus Engineering .......................................................... B1-1
B1.1 Fieldbus Engineering Process ..................................................................... B1-1
B1.2 Difference between Fieldbus and Analog Signal Process Control
Systems ......................................................................................................... B1-4
B1.3 Software Packages for Fieldbus .................................................................. B1-5
B2. System Design Considerations ........................................................... B2-1
B2.1 Considerations in Basic and Overall Design ............................................... B2-2
B2.2 Detail Design Considerations ...................................................................... B2-3
B2.2.1 Investigation of Number of Field Devices connected to
an H1 Segment ............................................................................... B2-4
B2.2.2 Selection of Fieldbus Cable and Wiring Method .............................. B2-5
B2.2.3 Design of FF Device Grouping per Segment ................................... B2-8
B2.2.4 Expansion and Modification of Existing System .............................. B2-8
B3. System Construction Considerations ................................................. B3-1
B3.1 New Construction of Fieldbus Process Control System ............................ B3-1
B3.1.1 Mounting Terminators ..................................................................... B3-3
B3.1.2 Mounting Couplers ......................................................................... B3-3
B3.1.3 Cabling ........................................................................................... B3-4
B3.1.4 Installing an Intrinsic Safety Barrier ................................................. B3-4
B3.1.5 Handling the Shield Mesh ............................................................... B3-4
B3.1.6 Connecting the Fieldbus Cable and Handling the Shield Mesh for
Fieldbus Communication Module .................................................... B3-4
B3.2 Reusing Existing Cables .............................................................................. B3-5
B4. System Startup Considerations ........................................................... B4-1
B4.1 Tool Necessary for Startup ........................................................................... B4-1
B4.2 Technologies and Expertise Necessary for Startup ................................... B4-2
B4.3 Labor Savings in Startup Work .................................................................... B4-3
B5. System Maintenance Considerations .................................................. B5-1
B5.1 Daily Maintenance ......................................................................................... B5-1
B5.2 Inspection and Maintenance ........................................................................ B5-2
B5.3 Maintenance Management (Maintenance Plan, Device Management,
Audit Trail) ..................................................................................................... B5-3
B5.4 Evolution of Maintenance ............................................................................. B5-3

TI 38K03A01-01E Sep.01,2002-00

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