Overview of Communication Standards relating to Motion Control Systems

Frederick M. Proctor

John L. Michaloski

National Institute of Standards and Technology

100 Bureau Drive, Stop 8230

Gaithersburg, MD 20899-8230

### Abstract

This report surveys the international communications standards that
affect the application and development of motion control technology. The
scope of motion control covered includes applications as diverse as
robotics, packaging machinery, discrete parts machining and
manufacturing, and food processing. In addition, motion controllers no
longer interface only to hardware devices, but are integrated into
higher levels of control architectures. Standards are being developed
within individual commercial application areas, not according to
commonality of computers, hardware, or physical requirements of motion
control. This has lead to a proliferation of standards, which presents
dilemmas to users, vendors and integrators. Criteria for deciding which
standards to support start with technical requirements, but equal weight
must often be given to availability of compatible products, and to
industry market trends.

[Abstract 1](#abstract)

[Introduction 3](#introduction)

[Motion Control Standards Issues 3](#motion-control-standards-issues)

[Breadth of Domain 3](#breadth-of-domain)

[Motion Controller Elements 3](#motion-controller-elements)

[Market Dynamics 4](#market-dynamics)

[Market Share through Standardization
5](#market-share-through-standardization)

[Formal Standardization 5](#formal-standardization)

[Standards Bodies 5](#standards-bodies)

[IEC and ISO 5](#iec-and-iso)

[ANSI 6](#ansi)

[ISA 6](#isa)

[CEN and CENELEC 7](#cen-and-cenelec)

[DIN 7](#din)

[BSI 8](#bsi)

[Motion Control Standards Landscape
8](#motion-control-standards-landscape)

[Bit Level Communication Standards
11](#bit-level-communication-standards)

[AS-Interface 11](#as-interface)

[CANBus 11](#canbus)

[Interbus 12](#interbus)

[Seriplex 12](#seriplex)

[Device Level Communication Standards
13](#device-level-communication-standards)

[CANOpen 13](#canopen)

[DeviceNet 13](#devicenet)

[FIREWIRE 14](#firewire)

[MACRO 15](#macro)

[SERCOS 15](#sercos)

[Smart Distributed System (SDS) 16](#smart-distributed-system-sds)

[EN 50325 16](#en-50325)

[Field Level Communication Standards
17](#field-level-communication-standards)

[IEC 61158 (Fieldbus) 18](#iec-61158-fieldbus)

[Profibus 18](#profibus)

[Information: www.profibus.comIEC 62026
19](#information-www.profibus.comiec-62026)

[EN 50170 19](#en-50170)

[EN 50254 20](#en-50254)

[Control Level Communication Standards
20](#control-level-communication-standards)

[Ethernet 20](#ethernet)

[Profibus-FMS 22](#profibus-fms)

[ProfiNet 22](#profinet)

[ControlNet 23](#controlnet)

[High Speed Ethernet (HSE) 23](#high-speed-ethernet-hse)

[EtherNet/IP 24](#ethernetip)

[Network Comparisons 24](#network-comparisons)

[Conclusion 30](#conclusion)

[Standards Glossary 31](#standards-glossary)

[Acknowledgments 32](#acknowledgments)

[Disclaimer 32](#disclaimer)

# Introduction

Control of moving parts is basic to modern industry, supporting
applications as varied as food processing, medicine, and aerospace
manufacturing. Motion control has evolved from its origins in mechanical
devices for regulating and transforming engine power, into today's
computers ranging in size from tiny embedded chips to networks of
high-performance workstations. This evolution has enabled manufacturers
to cut costs and improve quality by integrating motion control with
higher levels of factory control software. Standards are playing an
increasingly important role in this integration.

The primary goal of standardization is to enable interoperability of
systems. Standards can relate to physical equipment, such as motors,
data, such as process plans, and software, such as part programming
languages. Further, standardization must include interfaces involved in
vertical integration.

A problem faced today by users, vendors, and integrators of motion
control technology is the profusion of standards, especially in the
communications area. Deciding which standards to support requires users
to take into account technical requirements, product availability, and
industry trends. The purpose of this report is to survey the
international communications standards that affect the application and
development of motion control technology. The report will start by
identifying the standardization issues affecting motion control. Next,
the report will present an overview of the standards bodies and their
standards development processes. Finally, a summary and comparison of
the proliferating communication standards relating to motion control
will be given.

# Motion Control Standards Issues

## Breadth of Domain

Motion control is a broad domain that spans a variety of applications,
includes a wide range of technology, and is comprised of many different
functions. Application demands range from simple position control of a
single axis, through coordinated control of multiple axes, with cross
coupling, dynamic compensation, and integration with process parameters.
Motion control technology encompasses sensors for proximity, position,
velocity, acceleration, force, and temperature, and actuators such as
electric rotary and linear motors, hydraulic or pneumatic pistons,
piezoelectric or magnetostrictive actuators, and
micro-electro-mechanical system (MEMS) devices. Motion control
functionality ranges from control of the moving device itself using
current or other motive forces at the microsecond time scale, through
high-level programmed motion with time scales of minutes or longer, and
all the stages in between. These many dimensions of motion control make
standardization a complex task, and the natural tendency to focus on
particular application areas has led to a proliferation of standards
that are all related yet all different.

## Motion Controller Elements

Basically, a motion controller receives signals from sensors and
operator devices, processes them using defined control laws, and
generates the required output signals to drive an actuator. Figure 1
illustrates a controller design from a high-level architecture
standpoint -- consisting of a controller, IO, operator interface, and
communications. As part of manufacturing operations, motion controllers
must also rely on cross-factory and enterprise-wide communications,
which is shown as part of the architecture as well. Each of the elements
of the motion controller architecture is a candidate for
standardization. However, it is in the area of communications that the
proliferation of standards has occurred.

![](media/image1.wmf)

Figure 1.High Level Controller Architecture

The trend in machine controller integration is toward the use of
communication networks to simplify wiring, programming, and maintenance.
The proliferation of communication standards reflects this networking
trend and offers a range of functionality. Sensor/actuator networks are
used at the low cost and complexity end. Field and device networks
provide communication to distributed peripherals, such as IO modules,
drive units, and operator terminals, as well as other controllers.
Enterprise communication networks provide vertical integration to
management execution systems (MES), which focus on the operation of
mechatronic systems and on the control of processes, used in design,
process planning, quality control, accounting, forecasting, and other
resource planning activities. Specific communication network standards
will be compared later in the report.

## Market Dynamics

Low costs for industrial automation can be achieved by using commodity
hardware from the computing and communication markets. This is evidenced
by the high level of interest in Ethernet, and Firewire as motion
controller communication networks. However, the accompanying rapid pace
of development in the computing and communication market also means that
products will be available for desktop computers long before they appear
in industrial control systems. Nevertheless, the trend toward adopting
desktop technology on the shop floor means that the industrial control
market may be poised to benefit more quickly than it has in the past.

## Market Share through Standardization

Examples from the computing and communication industry have shown that
vendors who offer up their proprietary solutions as standards have the
potential to increase market share. This is especially true when
established vendors align behind a single standard to position
themselves ahead of their competition*.* Initially this is to the end
user's advantage, but the reaction among those vendors left out is
sometimes to start a competing standard. The result is that the end
users may be no better off than before. One purpose of application
users' groups is to decide which of the many applicable standards their
members will support strategically. Effective users' groups often
include suppliers so that a reasonable agreement can be reached without
causing turmoil in the market.

## Formal Standardization

Formal standardization through national or international standards
bodies may aid stability in the marketplace, but in some cases it has
the reverse effect. This is the case with official, enforceable
standards that are mandated by governments or other public agencies. In
these cases, suppliers of nonconforming technologies are at a severe
disadvantage. Recognizing this, standards bodies often write official
standards with parts that include several competing technologies. This
has the effect of leveling the market so that a single company or
country is not given undue dominance. Unfortunately, it also means that
end users who agree to a particular standard find themselves with
incompatible solutions, each a part of the standard but no two that are
interoperable.

# Standards Bodies

Standards bodies initiate, develop, disseminate for voting, publish, and
maintain standards. They range from national bodies, through regional
bodies, to international bodies. A national body typically participates
in regional or international bodies through a Technical Advisory Group
(TAG).

## IEC and ISO

The International Electrotechnical Commission (IEC) prepares and
publishes international standards for all electrical, electronic and
related technologies. IEC is a worldwide standards body, with
participating members from more than 50 countries. The IEC's mission is
to promote, through its members, international cooperation on all
questions of electrotechnical standardization and related matters, such
as the assessment of conformity to standards, in the fields of
electricity, electronics and related technologies. The IEC charter
embraces all electrotechnologies including electronics, magnetics and
electromagnetics, electroacoustics, telecommunication, and energy
production and distribution, as well as associated general disciplines
such as terminology and symbols, measurement and performance,
dependability, design and development, safety and the environment.

The International Organization for Standardization (ISO) is a worldwide
federation of national standards bodies from some 130 countries, one
from each country. The mission of ISO is to promote the development of
standardization and related activities in the world with a view to
facilitating the international exchange of goods and services, and to
developing cooperation in the spheres of intellectual, scientific,
technological and economic activity. ISO's work results in international
agreements that are published as International Standards.

Both IEC and ISO are organized into Technical Committees (TC),
Subcommittees (SC), and Working Groups (WG) whose participants do the
work of standardization.

IEC and ISO are made up of members that are the national body most
representative of standardization in its country. Thus, only one body in
each country may be admitted to membership. The U.S. member body of IEC
and ISO is the American National Standards Institute (ANSI). ANSI
designates Technical Advisory Groups (TAG) whose primary purpose is to
develop and transmit the member's positions on activities and ballots.

IEC and ISO differ in that IEC focus on electrical standards, and ISO
focuses on mechanical standards. The difference between the two domains
has blurred since the advent of computers and related electronic data
standards. As a result, many standards are released with joint IEC/ISO
designations.

IEC and ISO standards are designated with the prefix IEC or ISO,
respectively, followed by the standard number.

Related Standards: ISO 11898 (CAN), IEC 61158 (Fieldbus), IEC 62026

Information: www.iec.ch, www.iso.ch

## ANSI

The American National Standards Institute (ANSI) is the administrator of
the United States voluntary standardization system. ANSI facilitates
development of American National Standards (ANSs) by establishing
consensus among qualified groups, and by proscribing and enforcing
procedures. ANSI is the sole U.S. representative and dues-paying member
of ISO and IEC, and accredits TAGs that serve these organizations.

Related Standards: ANSI/ISA-S50.02 (Fieldbus), ANSI/EIA 709.1 (LonTalk)

Information: www.ansi.org

## ISA

ISA is an international, nonprofit, educational organization founded in
1947 as the Instrumentation Society of America, but now known as the
Instrumentation, Systems, and Automation Society. ISA fosters
advancement in the theory, design, manufacture, and use of instruments,
computers, and systems for measurement and control. ISA publishes
*Motion Control* magazine.

ISA is an ANSI-accredited standards developer and its SP50 Subcommittee
serves as the U.S. Technical Advisory Group for IEC SC65A/WG4, Interface
Characteristics.

ISA standards are designated with the prefix ISA, followed by the
standard number. ISA standards may be jointly published with ANSI or
other organizations.

Related Standards: ANSI/ISA-S50.02 (Fieldbus)

Information: www.isa.org

## CEN and CENELEC

CEN (the European Committee for Standardization) and CENELEC (the
European Committee for Electrotechnical Standardization) are the
European equivalents of ISO and IEC, respectively. They are official
standards bodies recognized by the European Commission, responsible for
publishing standards for the European market. CEN and CENELEC voting
members include: Austria, Belgium, Czech Republic, Denmark, Finland,
France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg,
Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and the United
Kingdom.

Under a procedure formalized as "The Vienna Agreement", CEN may elect to
transfer execution of European standards to ISO or to establish its own
TC. Otherwise, a CEN Technical Committee is established with national
delegations of experts convened by CEN members. The CEN TC must take
into account any relevant work in ISO or elsewhere falling within its
scope. The results of this work can then be offered to ISO once the CEN
standard is complete.

With CENELEC, proposed standards originating in Europe are offered to
IEC with the request that they be undertaken at international level. If
IEC does not want to undertake the work, or if it cannot meet the target
dates, the work commences at CENELEC for Europe. If IEC undertakes the
work, parallel IEC/CENELEC procedures aim at identical worldwide and
European standards. Once CENELEC work has commenced, all work on the
same subject that may be taking place in individual European nations is
immediately stopped.

CEN and CENELEC standards are designated with the prefix EN, followed by
the standard number.

Related Standards: EN 50170, EN 50254, EN 50295, EN 50325

Information: www.cenorm.be, www.cenelec.org

## DIN

Deutsches Institut für Normung (DIN) is the German national standards
body that reports to CEN and CENELEC.

DIN standards are designated with the prefix DIN, followed by the
standard number.

Related standards: DIN 19245 (Profibus), DIN 19258 (Interbus-S)

Information: www.din.de

## BSI

The British Standards Institution (BSI) is the United Kingdom's official
standards making body. BSI is a non-profit distributing organization
that is independent of government, industry and trade associations. BSI
works with manufacturing and service industries, businesses and
governments to facilitate the production of British, European and
international standards.

BSI standards are designated with the prefix DD, followed by the
standard number.

Related standards: DD 238 (Foundation Fieldbus), DD 241 (ControlNet)

Information: www.bsi.org.uk

# Motion Control Standards Landscape

As a consequence of the breadth of the motion control domain,
communications standards to integrate motion control systems have
proliferated. This would not present a problem if each standard covered
a different part of motion control functionality, but this is not a
case. The available communication standards cover a wide range of
capability and cost ranging from high-speed networked IO subsystems
standards to distributed communications standards for integrating all
machines on the shop floor into the wider enterprise. Numerous competing
communication standards are available to interface the motion controller
to the device, shop floor, and IO. Further, application domain
communication standards compete with other domain communication
standards as well as communications standards from the PC industry. In
fact, many PC communications standards have been adapted to the factory
floor to provide built-in redundancy and durability, so that all the
devices remain connected despite the harsh conditions often found in a
factory environment.

The value of the motion control and larger input/output device markets
has even led to companies positioning themselves for market dominance by
offering their protocols as a standard. As a result, there are
incompatible standards that cover equivalent areas, such as device
networks. This causes problems for buyers and suppliers alike. It is
simply too costly to support all the standards.

Formal standardization would seem to solve the problem, but in some
cases it has had the opposite effect. In Europe especially, where
conforming to a standard is often a contractual requirement for public
works projects, standards have arisen which simply include incompatible
industry standards. This makes the problem worse: two users may each
agree to use a single standard, but their systems will be incompatible.

Given this state of affairs, a survey of existing standards will be
reviewed based on four levels of factory communication: business,
control, device and bit level. Table 2 summarizes communication
performance by level.

Table 1. Industrial Automation Communication Hierarchy Characteristics

+-------------+----------------+-----------+--------+----------------+
|             | Primary        | Network   | Data   | Response Time  |
|             |                |           |        |                |
|             | Use            | Size      | Size   |                |
+-------------+----------------+-----------+--------+----------------+
| Business    | Enterprise     | Large     | Large  | \< seconds     |
| Level       |                |           |        |                |
|             | MIS            | \>100     |        |                |
|             |                | nodes     |        |                |
+-------------+----------------+-----------+--------+----------------+
| Control     | Peer-to-Peer   | Moderate  | Medium | \<100 msec     |
| Level       |                |           |        |                |
|             | Remote IO      | \< 100    |        |                |
|             |                | nodes     |        |                |
+-------------+----------------+-----------+--------+----------------+
| Device      | Smart IO and   | Small     | Small  | 10-100 msec    |
|             |                |           |        |                |
| Field       | S              | \< 64     |        |                |
|             | ensor-Actuator | nodes     |        |                |
|             | Control        |           |        |                |
+-------------+----------------+-----------+--------+----------------+
| Bit Level   | Binary IO, IO  | Small     | Small  | \<10 msec      |
|             | blocks and     |           |        |                |
|             | S              | \< 64     |        |                |
|             | ensor-Actuator | nodes     |        |                |
|             | Control        |           |        |                |
+-------------+----------------+-----------+--------+----------------+

Business level communication is responsible for connecting the
industrial automation on the plant floors with the business-level
enterprise using either Wide Area Networks (WAN) or Local Area Networks
(LAN) technology. Business level communication provides critical
information for production planning, supply chain management and for
work-in-process (WIP) tracking, for creating a real-time relational
database of production information, and for providing real-time links to
the corporate enterprise resource planning (ERP) and financial systems.

Control level communication is based on LAN networks that provide
broadcast and point-to-point messaging between automation nodes, and
perhaps to other networks via bridges. Control level networks are used
for data gathering, interprocess exchange of control data and sequencing
information, and remote access.

Device or field level communication provides cost-effective cabling and
connectivity to intelligent devices (actuators, sensors, operator
interfaces, controllers) that correspond to the emergence of "Smart IO"
devices (i.e., sensor/actuators with device profiles and an Application
API corresponding to Level 7 of the ISO Communication Model). Given the
standardization of IO-access through IO networks, the concept of a
"softPLC" has become a reality in the marketplace. Instead of large PLCs
(1000s of IO points grouped into IO blocks), functionality is decomposed
into station-level units. With the emergence of smart IO devices, the
decomposition is going a step further, toward specialized
component-based IO handlers.

Device and field are terms that come from different application domains
but refer to similar functionality within IO networks. Field-level
generally refers to networks designed as digital replacements for 4-20
mA transmission in process control industries, while device-level
generally refers to IO in discrete manufacturing applications and
controllers. However, the applicability of any device and field
standards is not restricted to a particular domain, as there is much
overlap in capability. In fact, a struggle for power between the control
system suppliers and field device suppliers deadlocked the international
fieldbus standardization effort for years.

Bit-level communication deals with the lowest level of automation (at
the actuator and sensor level) and provides low-cost networks for
connecting binary products, such as sensors, actuators, valves, and
relays, with higher-level control devices, such as programmable logic
controllers (PLCs), PCs, computer numerical controls (CNC), or
distributed control systems (DCSs). Communication solutions at this
level are often called sensor-actuator busses with deterministic,
real-time protocols to transmit control and device data, configure the
system architecture, power the devices, and monitor the network.
Bit-level communication is similar to device-level communications,
however, it usually offers a simpler, less flexible, but more
deterministic networking solution. Because of the overlap of
functionality between Bit-Level and Device-Field-Level, many Bit-level
communication standards are used as Device or Field level communication
standards.

Figure 2 classifies a sampling of communication standards within the
realm of the industrial automation communication hierarchy.

![](media/image2.wmf)

Figure 2. Survey of Communication Standards Relevant to Motion Control\
(Source: Control Engineering Magazine)

The chart shows the proliferation of applicable motion control
communication standards is most dramatic in the bit and device level.
Many of the standards extend an existing network standard that defines
Layer 1 (Physical) and Layer 2 (Transport), by adding Layer 7
(Application). For example, CANOpen and DeviceNet each adds a similar,
but unique, Layer 7 application standard, while both rely on the CAN bus
standard for communication Layers 1 and 2.

Motion control typically relies on servomotors in the field of factory
automation. The control target can be position, speed, or force, among
others. However, motion control is never "standalone" and motion control
relies on other IO devices in fulfilling the requirements of the
application. Further, there is an overlap between the concept of IO and
a motion control product. For example, for many given networks (such as
DeviceNet) there exist servo axis products that attach to the network.
In addition, most networks establish a device profile for describing the
capabilities of a servo axis. A survey of the major standards relating
to IO and motion control will be reviewed and compared. The breakdown of
the survey is done by bit-level, device-level and control-level, even
though many network standards cross boundaries, and some don't really
provide any application programming interface. See Tables 2, 3 and 4 for
comparisons between varying protocols.

## Bit Level Communication Standards

### AS-Interface

EN 50295, "Low-voltage switchgear and controlgear - controller and
device interface systems- actuator sensor interface (AS-Interface)," or
AS-I, is a European standard carried out by CENELEC technical committee
TC17B. AS-I was approved in 1998.

AS-I was designed as a low-cost alternative to more complex fieldbuses,
suitable for networking simple binary devices. AS-I (often pronounced
"azzi") uses a single yellow cable that contains both data and power.

Power comes from a 24V DC supply that is fully isolated from the data
signals. The signal is modulated to ensure noise immunity. The network
is typically rated up to 8A, but higher currents can be drawn provided
voltage drops in the network conform to the specification. A separate
black cable and power supply can be used if needs demand it.

Each AS-Interface network has one master and can include up to 31 slave
devices. Slaves can connect up to four devices, supporting 124 inputs
and 124 outputs. On a fully loaded network, the maximum latency is 5ms.
Cycle times are faster with fewer devices. Network messages have four
data bits that may be used as inputs or outputs, so that AS-I can be
used for analog devices by splitting data across cycles. In addition to
data bits, the protocol transmits other information, such as status bits
that can be used for diagnostics.

Information: [www.as-interface.com](http://www.as-interface.com/)

### CANBus

CAN or ISO 11898, "Road vehicles- interchange of digital information-
controller area network (CAN) for high-speed communication)" was
originally developed by the Bosch Corporation for use in automobiles.
CAN is based on the ISO 7498 Open Systems Interconnect (OSI) model for
the Physical and Transport Layers. The standard does not specify an
Application Layer. CAN was approved as ISO 11898 in 1993.

CAN is a high-speed network, meeting the Society of Automotive Engineers
(SAE) Class C network requirements for 1 megabit/second data transfer
and 5 millisecond latency. CAN chips are available in high volumes from
manufacturers such as Phillips, Intel, and Motorola. The chips can be
interfaced to various transmission media, such as one-wire, two-wire, or
fiber optic.

CAN is a multi-master network, where the bus access arbitration is based
on the message identifier. The message identifier is 11 bits, supporting
2048 messages. An extended message identifier of 29 bits was introduced
to allow a larger number of message types. The data field of messages
can be up to 8 bytes wide. Messages that require larger data fields must
be sent in segments. CAN messages use 16-bit cyclic redundancy checking
(CRC-16) for error detection and correction. With a full 8-byte data
message, the data to message size is 57%, with the rest consisting of
overhead for the message identifier, control, and framing bits.

CAN data rates depend on trunk distance: 1 megabit/second for up to 40
meter distances, 125 kilobits/second for up to 500 meter distances, and
50 kilobits/second for up to 1 kilometer.

The standard lacks an Application Layer protocol, which has led to its
use in a variety of applications other than automobiles, including
industrial automation, medical equipment, and building automation.
Several application layer protocols have been developed for industrial
automation, including DeviceNet, Smart Distributed System (SDS), and
CANOpen.

### Interbus

Interbus was developed in 1984 by Phoenix Contact and approved as German
standard DIN 19258. Interbus is promoted by the Interbus Club, a
member-funded, non-profit organization established to maintain and
advance the Interbus network standard. The Interbus Club was initially
founded in Europe in 1993. Currently there are over 600 members in 15
countries.

Interbus is a master-slave hardware ring network with cabling options
that allow for twisted pair or fiber optic transmission media. The data
link layer supports full duplex communication with no arbitration and
CRC error correction. Interbus supports up to 512 devices and a total of
4096 digital input and 4096 digital output points or combinations of
digital and analog signal types. Interbus is commonly implemented using
the RS-485 serial digital protocol with a five-wire cable.

See Tables 2-4 for details on Interbus and comparisons with other
protocols.

Information: www.interbus.com, www.ibsclub.com

### Seriplex

Seriplex (Serial Multiplexed Control Bus) is an industrial control bus
developed by Automated Process Control and patented in 1987. The
Seriplex Technology Organization (STO) is an independent, non-profit
corporation, created to support and promote Seriplex Control Bus
technology in the general marketplace. Seriplex is Part 5 of
international standard IEC 62026.

Seriplex is a deterministic, serial multiplexed, intelligent,
distributed IO system, providing both master/slave and peer-to-peer IO
control and logic. It uses a shielded four-conductor cable. Two of the
conductors deliver +12 VDC power or +24 VDC power to the bus. The other
two conductors provide the data signal and clock signal that controls
network timing.

Seriplex networks consist of IO devices with integrated Seriplex chips,
or an IO block with a Seriplex chip into which devices are wired. In
Master/Slave mode, the chip provides for the communication of IO device
events to a host CPU. In Peer-to-Peer mode, there is no host CPU. Events
occurring at each device are communicated directly between IO blocks or
devices containing an embedded chip. These events are acted upon at the
device level and are based on the logic functions programmed into the
chips.

Information: [www.seriplex.org](http://www.seriplex.org/)

## Device Level Communication Standards

### CANOpen

CANOpen, like DeviceNet and SDS, is an application layer on top of CAN,
advocated by the CAN in Automation (CiA) group based in Germany. CANOpen
builds on the Physical and Transport Layers of CAN in a family of
profiles that consists of the Application Layer and Communication
Profile (CiA DS 301), various frameworks and recommendations (CiA
DS-30x), and various device profiles (CiA DS-40x).

The DS 301 Application Layer and Communication Profile defines how data
is exchanged between devices and describes the interface to the
underlying communication medium, including which data has to be
transmitted and with which services.

The DS-40X device profiles aid systems integration and device
standardization by specifying guidelines by which two independent
manufacturers can produce standardized devices. Guidelines include
mandatory device characteristics that guarantee correct network
operation, and a profiling mechanism that allows manufacturers to
provide options and future enhancements.

Device-level profiles include digital and analog IO modules, motor
drives, encoders, motion controllers, and operator displays.

Information: [www.canopen.de](http://www.canopen.de/)

### DeviceNet

DeviceNet, like CANOpen and SDS, is an application layer on top of CAN,
advocated by the Open DeviceNet Vendors Association (ODVA). DeviceNet
was originally developed by Allen-Bradley, but is now an open standard
that may be obtained from the ODVA. Any company manufacturing DeviceNet
products may join ODVA and participate in technical working groups that
are developing enhancements to the DeviceNet Specification. Buyers of
the DeviceNet Specification receive an unlimited, royalty-free license
to develop DeviceNet products. The ODVA is comprised of over 300
members, including ABB, Cutler-Hammer, GE Fanuc, and Rockwell
Automation/Allen-Bradley.

The DeviceNet specification includes Volume 1, the Application Layer,
and Volume 2, Device Profiles. The Application Layer adds to the CAN bus
the concepts of connections, and data transfer models including strobed,
polled, cyclic, change-of-state, and application-triggered. Device
addressing may be peer-to-peer with multicast, multi-master, or
master-slave. Device Profiles promote interoperability by defining
standard device models that support common identification and status
data. Device profiles contain a definition of the device object model, a
list of the object classes present in the device, definitions of data
formats, and definitions of configurable parameters. The DeviceNet
object model organizes the attributes, services, and behaviors of a
product.

The DeviceNet specification is more specific than the standard CAN
protocol with respect to some physical properties. These include
allowable topologies, system grounding, use of thick and thin media,
termination, and power distribution. The DeviceNet trunkline-dropline
topology provides separate twisted pair buses for both signal and power
distribution. Up to 64 addressable nodes are supported.

Device-level application layer include profiles for digital and analog
IO, motor drives, encoders, and position controller.

Information: www.odva.org

### FIREWIRE

Firewire is the physical layer that was developed by Apple Computer and
standardized as IEEE-1394. It is widely used in the computer and
consumer electronics industries. (Apple collects royalties on the
Firewire chip sets.) Because of its popularity in the computer and
consumer electronics industries, the Firewire chip set enjoys the
advantage of low cost.

Firewire provides a hardware and software standard for transporting data
at 100, 200, or 400 megabits per second (Mbps) tha allows mixing of 100,
200, and 400 Mbps devices on a bus. Device addressing is 64 bits wide,
partitioned as 10 bits for network Ids, 6 bits for node Ids and 48 bits
for memory addresses. The result is the capability to address 1023
networks of 63 nodes, each with 281 terabytes of memory. Firewire is
purely a digital interface, so there is no loss of data integrity.
Firewire media includes either small, thin serial cable, which can be
replaced, or large and more expensive interfaces. Firewire does not need
terminators, device IDs, or elaborate setup and is hot pluggable, so
users can add or remove 1394 devices with the bus active. The Firewire
topology supports daisy chaining and branching for true peer-to-peer
communication. Firewire supports two types of data transfer:
asynchronous and isochronous. Asynchronous transport is sent to a
specific address and an acknowledgment is returned. Isochronous data
channels provide guaranteed data transport at a pre-determined rate,
which provides time-critical data transmissions.

Firewire is being promoted as a standard, low-cost, high-speed,
industrial, digital, single-cable serial bus suited for real-time motion
control applications. A number of companies have developed drive
communications systems using the IEEE-1394 physical layer. Ormec has
developed a package called ServoWire. National Instruments offers
FW-7344 multi-axis, distributed motion controllers that uses the
high-speed FireWire network bus. Nyquist Industrial Control offers a
PCI-based FireWire interface module called the NY3910 FireWire
Connection. Adept Technology recently launched SmartAmps connected over
a digital network. Acroloop recently began offering an IEEE-1394
interface.

The Firewire standard is not intended to interface to servo drives, so
applications based on one companies' Firewire product are incompatible
with another companies. According to the ARC Advisory Group, Yaskawa,
NEC and Mitsubishi have established a collaboration to develop a
FireWire-based digital servo drive interface.

Information: www.1394ta.org

### MACRO

MACRO (Motion And Control Ring Optical) is a specification for
connecting multi-axis motion controllers, amplifiers, and IO over a
single high speed fiber optic network. MACRO uses fiber optic or RJ-45
"thin wire" interfaces. The fiber optic interface allows the drives to
be up to 1 kilometer from the drive to the controller, and the RJ-45
interface allows the drives to be up to 1,000 feet from the controller.
MACRO's fiber optic interface technology provides total electrical noise
immunity. MACRO communicates at 125 megabits a second.

MACRO operates in a ring topology. Data is transmitted serially. Each
station on the ring has an "in" port for receiving data and an "out"
port for transmitting data. Nodes, residing at a station, can be
amplifier axes, IO banks, or communication interfaces to other devices.
A station can have one or several nodes, allowing for multi-axis
amplifiers with a single "in" and single "out" port. Data packets,
(groups of 96 bits of serial data), sent out by a motion controller or,
master node, are earmarked for a specific amplifier, or slave node. If
the data packet is not for an amplifier, it passes it on, unchanged. If
it is for the node, it copies the contents of the data packet (typically
commands), places feedback data into the packet in place of the command
data, and transmits the data packet.

Building MACRO into a product requires the MACRO gate array integrated
circuit. Currently the gate array is available from Delta Tau Data
Systems in 144 or 160 pin QFP packages and is designed for a 24 bit
microcontroller.

MACRO application layer provides the ability to pass commands of
different types from a controller to an amplifier, including position,
velocity, torque, phase current, and PWM values. MACRO's high data rate
allows closure of high performance servo loops, which can be split
between the controller and amplifier at any level.

Information: [www.macro.org](http://www.deltatau.com/dtmacro7.htm)

### SERCOS

SERCOS (Serial Realtime Communication System) is a digital interface for
communication between control systems and drives. SERCOS was approved as
international standard IEC 61491 in 1995 and as European standard EN
61491 in 1998. The SERCOS specification includes the physical layer,
including connectors. An optical fiber ring is used as transmission
medium. The maximum transmission rate is 2, 4, 8 or 16 megabit/second,
depending on the device design. Three communications types between CNC
and digital drive control elements can be realized with this interface:
nominal position, nominal speed, or nominal torque. The transmission of
nominal position is the recommended type for fast and highly precise
applications.

In one optical fiber ring up to 6 axes can be cyclically and parallel
supplied with new nominal positions values (nominal positions) every 0.5
ms. The SERCOS interface allows all drive-internal data, parameters and
diagnosis data to be displayed and entered by means of a
SERCOS-compatible CNC.

All drives on the SERCOS ring close loops synchronously, eliminating the
possibility of "beat" frequencies or harmonics appearing in the motion
control system. Feedback acquisition and command value executions are
performed in every drive at the same instant in time, making an
effective "snapshot" for control purposes.

Each segment (node-to-node) of a SERCOS ring can be up to 40 meters in
length using plastic fiber, 200 meters using 200 µm glass fiber, or 400
meters using 400 µm glass fiber. Total ring lengths are 10,000 meters,
50,000 meters and 100,000 meters respectively.

The maximum number of drops per fiber optic ring is 254. However, the
number of drives that can be serviced per ring depends on three
application requirements: communication cycle time, volume of
operational data, and communications speed required. SERCOS imposes no
limit to the number of rings that can be synchronized together.

SERCOS application layer provides capability for commanding axis
position, velocity, torque as well as block mode (drive internal
interpolation).

Information: www.sercos.org, www.sercos.com

### Smart Distributed System (SDS)

Smart Distributed System (SDS), like CANOpen and DeviceNet, is an
application layer on top of the CAN bus. SDS was introduced by Honeywell
Micro Switch in early 1993 and formally opened to other vendors the
following year. The SDS specification is currently under engineering
control of the SDS Council.

SDS specifies an Application Layer, Component Model, and a Physical
Layer. The Application Layer specifies services, such as read, write,
event generation and handling, and connection establishment for
multicast or peer-to-peer communication. The Application Layer also
includes protocols that define data and message types.

The Component Model Specification defines a hierarchical object-oriented
view of devices and their relationships.

The Physical Layer restricts the CAN physical layer specification. SDS
transmission speeds of 125K, 250K, 500K, and 1.0M bits/sec allow network
lengths of 1,500, 600, 300, and 75 feet, respectively. The trunk
consists of two-wire twisted shielded cable with optional two-wire bus
power cable and drain wire. There is a maximum of 32 nodes at 1.0M
bits/sec and 64 nodes at the lower transmission speeds.

Information: honeywell1.datareturn.com/sensing/prodinfo/sds

### EN 50325

EN 50325, "Industrial communication subsystem based on ISO 11898 (CAN)
for controller-device interfaces," is a proposed European standard being
carried out by CENELEC technical committee TC65CX. EN 50325 provides
official European standards status to two CAN-based application layer
protocols: DeviceNet and Smart Distributed System (SDS).

EN 50325 is divided into volumes, some of which are technically
equivalent to parts of international standard IEC 62026:

-   Volume 1, General

-   Volume 2, DeviceNet (IEC 62026-3)

-   Volume 3, SDS (IEC 62026-5)

Information: www.cenelec.org

## Field Level Communication Standards

The field-level refers to communications networks that link isolated
industrial field devices, such as sensors, actuators, and controllers.
The simplest industrial field technology is the 4- to 20-mA current
loop. An updated version of this protocol is the HART protocol (Highway
Addressable Remote Transducer), which uses the Bell 202 Frequency Shift
Keying (FSK) standard to superimpose digital signals at a low level on
top of the 4-20mA. This enables two-way communication of additional
information beyond the normal process variable to be communicated
to/from a smart field device. The HART standard will not be covered in
this paper, (see the HART Communication Foundation
<http://www.hartcomm.org/> for more information.)

The SP50 committee of the Instrument Society of America (ISA) was the
original focal point for a standardized fieldbus network, but the
ISA/SP50 and IEC committees meet jointly to facilitate the development
of an international standard. The IEC fieldbus standardization was led
by the Foundation Fieldbus, the result of the merging of two previously
incompatible fieldbus standards espoused by the Interoperable Systems
Project (ISP) and WorldFIP groups. FF membership is comprised of over
120 suppliers and users of control and instrumentation, including
Fisher-Rosemount, Siemens, Honeywell, and Elsag-Bailey. With its origins
in the process-control industry, Foundation Fieldbus principally targets
the local-area networking that connects instrumentation and control
devices on the factory floor.

In October 1999 after 14 years, seven protocols were added to the
proposed IEC 61158 fieldbus standard including protocols from
ControlNet, Profibus, Interbus, P-Net, WorldFIP, SwiftNet, and the
Fieldbus Foundation\'s high-speed Ethernet protocol that ultimately led
to approval of the standard. The Fieldbus Foundation endorses IEC 61158
and its conforming implementation, Foundation Fieldbus. Further,
Foundation Fieldbus specifies a high-speed communication Device
Description (DD) technology, which provides interoperability between
devices from different suppliers and was released in 1996.

In April 2000, concern was raised that essential parts of the newly
approved IEC 61158 fieldbus standard are protected by patents or patent
claims of certain companies. In response to this concern,
Fisher-Rosemount issued a public statement that patented technology
demonstrated to be essential to implement fieldbus specifications will
either be assigned to the Fieldbus Foundation or offered as a license to
Fieldbus Foundation members in good standing on a royalty free,
non-exclusive, worldwide basis.

Because the IEC 61158 Fieldbus specification contains a variety of
network protocol standards, some will be omitted from discussion,
including P-Net (Denmark), WorldFIP (France), or SwiftNet (developed by
Ship Star Associates working with Boeing Aircraft). Interbus, another
IEC 61158 network protocol, was discussed earlier; while ControlNet,
another IEC 61158 network protocol, will be discussed in the
Control-level network standards.

### IEC 61158 (Fieldbus)

IEC 61158, (or ANSI/ISA-50.02) "Fieldbus standard for use in industrial
control systems," is the culmination of over a decade of effort to
standardize a replacement for the analog 4-20 milliamp de facto standard
for field wiring of input/output devices. IEC 61158 is the
responsibility of IEC Working Group SC65C, with the U.S. TAG IEC/ISA
SP50 subcommittee.

IEC 61158 is divided into parts, following the ISO 7498 Open Systems
Interconnect (OSI) model for the Physical, Data Link, and Application
Layers: Part 2 is the Physical Layer, Parts 3 and 4, the Data Link Layer
Services and Protocol, and Parts 5 and 6, the Application Layer Services
and Protocol. Part 2, the Physical Layer, was approved in 1993. IEC
61158 fieldbus standard Parts 3 and 4 include protocols from IEC 61158,
ControlNet, Profibus, Interbus, P-Net, WorldFIP, SwiftNet, and the
Fieldbus Foundation\'s high-speed Ethernet protocol. In December 1999,
the International Electrotechnical Commission (IEC) approved the Final
Draft International Standard (FDIS) documents for the Data Link Layer
(DLL) and Application Layer (AL) of the IEC 61158 international fieldbus
standard. The Foundation Fieldbus specifications are a compliant subset
of IEC 61158.

Information: www.iec.ch, www.fieldbus.org, www.isa.org

### Profibus

Profibus (Process Field Bus) is a fieldbus standard for integrating
sensors, actuators, transmitters, drives and programmable logic
controllers. The Profibus User Organization (PNO) is the sponsoring
organization, representing manufacturing, users, and systems integrators
of Profibus components. Profibus consists of three specifications:
Profibus-FMS, Profibus-DP, and Profibus-PA. Profibus-FMS and Profibus-DP
are Volume 2 of European standard EN 50170. Profibus-FMS will be
discussed later in the Control level standards.

Profibus-DP (De-centralised Periphery) is a performance optimized
version of Profibus specifically dedicated to time-critical
communication between automation systems and distributed peripherals. It
is designed as a replacement for discrete wiring of 24 V and 4 to 20 mA
measurement signals.

Profibus-PA (Process Automation) is designed specifically for the needs
of the process automation industry. Profibus-PA provides for power and
data transmission over the same two wires, and can be used within areas
with high explosion risk using intrinsic safe transmission technology
according to IEC 1158-2. It operates either with intrinsic safe
transmission technology (IEC 1158-2) or standard transmission technology
(RS-485).

Profibus specifies the lowest two levels of the OSI protocol stack, the
Physical and Data Link Layers. The physical layer uses copper wire in
accordance with the US standard EIA RS-485. It uses a two-conductor
twisted pair cable, with optional shielding. Two cable versions with
different maximum distances are available. A specification for fiber
optic transmission for longer length and noise immunity is being
proposed.

Profibus uses the token passing method for communication between complex
stations (masters) and the master-slave method for communication between
complex stations and simple peripheral devices (slaves). This combined
method is called hybrid medium access. With the hybrid medium access
method of Profibus it is possible to implement a pure master-slave
system, a pure master-master system (token passing), and a system with a
combination of both methods.

### Information: [www.profibus.com](http://www.profibus.com/)IEC 62026

IEC 62026, "Control circuit devices and switching elements for
low-voltage switchgear and controlgear," provides official international
standards status to five device networks: AS-i, DeviceNet, Lontalk, SDS,
and Seriplex.

IEC 62026 is divided into six parts. Some of these parts are technically
equivalent to other standards:

-   Part 1, General Requirements (EN 50325-1)

-   Part 2, AS-I (EN 50295)

-   Part 3, DeviceNet (EN 50325-2)

-   Part 4, Lontalk (ANSI/EIA 709.1)

-   Part 5, SDS (EN 50325-3)

-   Part 6, Seriplex

Information: www.iec.ch

### EN 50170

EN 50170, "General purpose field communication systems," is a European
standard for fieldbuses that was made enforceable by the European
Commission for utilities and other public undertakings. EN 50170 was
approved in 1997, and originally conferred standards status on three
fieldbuses: P-Net (Denmark), Profibus-DP/FMS (Germany), and WorldFIP
(France). The UK proposed adding Foundation Fieldbus, Profibus-PA, and
ControlNet as amendments, so that these fieldbuses (and companies that
sold them) would not be left out. EN 50170 is comprised of the following
parts and amendments, some of which are equivalent to other standards:

-   Volume 1, P-Net (DK 502058, 502066)

-   Volume 2, Profibus-DP/FMS (DIN 19245)

-   Volume 3, WorldFIP (NFC 46601-46607)

-   Amendment A1, Foundation Fieldbus (DD 238)

-   Amendment A2, Profibus-PA

-   Amendment A3, ControlNet (DD 241)

Information: www.cenelec.org

### EN 50254

EN 50254, "High efficiency communication subsystem for small data
packages," is a downsizing of EN 50170 for applications with smaller
data size and lower data rates. It includes subsets of Profibus-DP and
WorldFIP, and adds Interbus-S:

-   Volume 1, General

-   Volume 2, Interbus-S (DIN 19258)

-   Volume 3, Profibus-DP (EN 50170-2)

-   Volume 4, WorldFIP/1 (EN 50170-3)

## Control Level Communication Standards

Control level communication is based on LAN networks that provide
broadcast and point-to-point messaging between automation nodes, and
perhaps to other networks via bridges. Control level communication
connects industrial devices: programmable logic controllers, numerical
controllers, robots, industrial computers, intelligent sensors and
actuators. At the control level, factory automation must provide access
to real-time data and information that can be used to optimize
manufacturing processes. MES systems can collect data from the machines
to continually monitor and improve the manufacturing process leading to
increased productivity and quality.

Ethernet technology is emerging as the primary control level network in
allowing seamless integration of factory and enterprise. Although not
suited for deterministic control in automation networking, Ethernet is
attractive because of its low cost, high speed, high bandwidth, widely
available, internationally standardized, and knowledgeable expertise is
readily available. Typically, many existing control level application
communication protocols are adapting their standards to run on
Ethernet's IEEE 802.3 Physical and Data Link standard, or are defining
open, standard gateways to connect Ethernet to the device level
networks.

### Ethernet

Ethernet specifies the OSI Model Physical layer 1, and the Data Link
layer 2. Ethernet was first specified in the late 1970's; and in 1985,
Ethernet II was released, which is basis for the IEEE 802.3 CSMA/CD
network standard. CSMA/CD stands for \"Carrier Sense Multiple Access,
with Collision Detection\" and is a network bus arbitration scheme. IEEE
802

Ethernet communicates at 10-Mbps with physical media options including
the original thick coaxial system, as well as thin coaxial,
twisted-pair, and fiber optic systems. Fast-Ethernet defines a 100-Mbps
rate and operates over twisted-pair and fiber optic media. Switched
Ethernet LANs use switches to connect individual hosts or segments. In
the case of individual hosts, the switch replaces the repeater and
effectively gives the device full 10 Mbps bandwidth (or 100 Mbps for
Fast Ethernet) to the rest of the network. In the case of segments, the
hub is replaced with a switching hub.

The Ethernet network has long been the network of choice at business
levels of manufacturing enterprises. Because of the low cost of Ethernet
products as well as existing corporate intranet/internet Ethernet
infrastructures, it is a long-standing desire to use Ethernet as a
"backbone" across the manufacturing enterprise to connect the bit-level
sensor, device, control, and business levels. A further appeal of
Ethernet is its connectivity as part of the World Wide Wide. Installing
web servers on I/O systems could transform access to these systems.
Local I/O web servers is possible with the emergence of Intelligent
Appliance (IA) silicon chips, as low cost, small footprint, that can
turn any electrical device into a self-contained web server that can
communicate wirelessly or over existing copper wire to other IAs. With a
Hypertext Transfer Protocol (HTTP) server embedded in the IO, the
ability to load a Web page to configure I/O points, test points,
configure event/reactions, or set up exception reports is possible. The
use of wireless Ethernet for mobile computing is also emerging on the
plant floor as another aspect to improve manufacturing operations. As an
example product, a handheld PC could be used to roam the plant floor in
an effort to diagnose factory floor controllers.

Overall, benefits that are seen from using Ethernet IO in factory
automation include:

-   Lower cost I/O (devices, wiring, and junction box savings)

-   Common network connection for all device types

-   Reduce the proliferation in the number of networks to be supported

-   Improved communications with enterprise Management Information
    Systems (MIS) applications

-   Networking infrastructure better able to support future information
    exchange needs

Although highly desirable, the use of Ethernet throughout the factory is
unrealistic as off-the-shelf Ethernet is non-deterministic due to its
bus arbitration scheme. Emerging factory automation Ethernet solutions
overcome the non-determinism by using full-duplex cabling in a switched
network star topology, that means that every device has its own
communication channel, precluding collisions. Buffering in the switch
guarantees queued delivery, providing guaranteed determinism. Yet, even
Switched Ethernet adapted for deterministic real-time networking is
still not suitable for all aspects of factory automation. As a passive
network, Ethernet cannot support bit-level factory automation
communication, as it does not supply the 24 V dc power required of
traditional two-wire devices, such as transmitters and valve
controllers. Further, Ethernet's basic copper wiring may not be
acceptable in harsher electromagnetic conditions. Ethernet's connectors
present a problem in many industrial applications where vibration and/or
fluids are present. This has lead to the development by various
companies and industry consortiums to develop Ethernet wiring and
connector standards to insure built-in redundancy and durability, to
guarantee that all devices remain connected despite the harsh conditions
often found in a factory environment.

Some industry consortiums use existing Ethernet standards and provide
gateways to connect to field and device level networks. Ethernet
solutions that require a gateway to allow the Ethernet and device
network to talk do not necessarily lessen wiring or equipment
requirements, speed up communications, nor significantly reduce costs.

Information:

Gigabit Ethernet Alliance - www.gigabit-ethernet.org

Internet Engineering Task Force - www.ietf.cnri.reston.va.us

IEEE 802 LAN/MAN Standards Committee - ieee802.org

Industrial Ethernet -- www.industrialethernet.org

### Profibus-FMS

Profibus-FMS (Fieldbus Message Specification) is designed for acyclic or
cyclic data transfers at medium speed between control equipment and
cell-level controllers. Profibus-FMS is part of Volume 2 of the European
standard EN 50170. Profibus-FMS uses the base Profibus specification
(see [Profibus](#profibus)) for the Physical and Data Link Layers, but
adds the Application Layer, the topmost (Level 7), using a subset of the
Manufacturing Message Specification (MMS) (ISO 9506) of the MAP
protocol.

Profibus FMS offers a full-featured networking profile operating at a
backbone level. Profibus DP is primarily a high-speed master-slave
network, and Profibus DP and FMS can coexist on the same wires. Because
of its intrinsic safety feature, Profibus PA is generally targeted for
process automation, and a gateway is required to interconnect Profibus
PA and Profibus FMS/DP on the same network.

Profibus FMS application services are a subset of the MMS (Manufacturing
Message Specification, ISO 9506) services, which have been expanded with
functions for communication object administration and network
management.

### ProfiNet

ProfiNet is sponsored by the Profibus Trade Organization's as a network
standard to link Ethernet TCP/IP at the automation systems level and
Profibus at the field level. ProfiNet is not a packaging of Profibus
over Ethernet. Each retains its own physical layer so that a gateway is
required between them to allow Profibus to work with Ethernet. Profinet
guarantees open, transparent communications between software
applications at all levels using using open industrial standards,
including TCP/IP, COM/DCOM, Remote Procedure Calls (RPC) and OLE for
Process Control (OPC) technologies. Profinet will allow users to monitor
Profibus devices remotely via Ethernet and the Internet. ProfiNet uses
direct routing of TCP/IP onto Profibus, enabling Internet technology and
Microsoft software to become more integrated with field devices. This
will enable web servers in field devices, and allow more complex field
devices to use common services via DCOM.

Information: [www.profibus.com](http://www.profibus.com/) or
[www.profinet.com](http://www.profinet.com/)

### ControlNet

ControlNet is a device network developed by Rockwell/Allen-Bradley and
made available as an open standard in 1996. ControlNet is designed for
real-time, high-speed integration of control systems such as coordinated
drive systems, weld control, motion control, vision systems, complex
batch control systems, process control systems, and systems with
multiple controllers and human-machine interfaces. ControlNet targets
systems with multiple PC-based Controllers, PLC-to-PLC and PLC-to-DCS
communication.

ControlNet views industrial application as consisting of three layers.
The information layer supports plant-wide data collection and program
maintenance, and uses protocols such as Ethernet. The automation and
control layer supports real-time IO control, interlocking, and
messaging, and is the target for ControlNet. The device layer supports
cost-effective integration of individual devices, and it uses fieldbus
protocols such as DeviceNet or Foundation Fieldbus.

ControlNet International, an independent organization for users and
vendors of ControlNet products, was formed in July 1997. The
organizations manages the ControlNet Specification and supports
worldwide growth of ControlNet by developing test software, providing
independent compliance testing, publishing the ControlNet product
catalog, and sponsoring design and implementation training.

ControlNet supports a maximum data transfer of 5.0 megabit/second using
coaxial cable or fiber optic transmission media. Devices are powered
externally. There is a limit of 99 addressable nodes, but no limit on
the number of IO data points that can be integrated.

ControlNet is based on a producer/consumer communication model. This
model permits all nodes on the network to simultaneously access the same
data from a single source. Network access is controlled by a time-slice
algorithm called Concurrent Time Domain Multiple Access (CTDMA), which
regulates a node's opportunity to transmit in each network interval,
which is configurable and can be as small as 2 milliseconds.

ControlNet was standardized in Europe in 1998 as Amendment A3 to EN
50170, and is being standardized in the UK as DD 241.

Information: www.controlnet.org

### High Speed Ethernet (HSE)

The IEC 61158 Foundation Fieldbus physical layer standard is low-speed
(also known as the ISA/SP50 H1). Foundation Fieldbus expanded its effort
to support 100 megabit/second High-Speed Ethernet (HSE) (originally
known as the ISA/SP50 H2). The HSE specifications were passed in 1998.
FF\'s HSE protocol is presently the only Ethernet protocol included in
the IEC 61158 standard and is included as well in the CENELEC EN 50170
Euronorm.

HSE uses Ethernet technology and runs at speeds from 100 Mbit/s to 1
Gbit/s or higher. HSE runs 100 meters from switch to device using
standard twisted-pair (two-pair) wire and up to 2,000 meters from switch
to device on fiber-optic cable. Using fiber-optics also allows HSE to
pass through hazardous areas. Combining HSE\'s media options with H1\'s
media options (bus power, intrinsic safety, and fiber) can solve almost
any installation challenge.

HSE supports all Foundation Fieldbus 31.25 kbit/s (H1) functions, such
as Function Blocks and Device Description Language, and allows
Ethernet-based devices to interface with H1 devices through a linking
device. H1 devices can communicate peer-to-peer to another H1 device, on
the same link or another linking device, without the need for host
system intervention. HSE devices communicate using Ethernet TCP/IP.

### EtherNet/IP

Ethernet Industrial Protocol (EtherNet/IP) is an open industrial
networking standard developed by the Open DeviceNet Vendor Association
(ODVA) that supports implicit messaging (real-time I/O messaging),
explicit messaging (message exchange), or both and uses commercial
off-the-shelf Ethernet communication chips and physical media.
EtherNet/IP allows device-level data to be accessed from the Internet.

EtherNet/IP is based on existing standards including:

-   IEEE 802.3 Physical and Data Link standard,

-   Ethernet TCP/IP (Transmission Control Protocol/Internet Protocol)
    protocol suite,

-   Control and Information Protocol (CIP), the protocol that provides
    real-time I/O messaging and information/peer-to-peer messaging used
    by ControlNet and DeviceNet networks.

EtherNet/IP networks support an active star topology in which devices
may be connected point-to-point in a Switched Ethernet real-time
configuration allowing support of both 10 and 100M bit/s products.
EtherNet/IP allows large amounts of messaging data, 1500 bytes maximum
per packet. Standard twisted-pair and fiber-optic cable are fully
functional with EtherNet/IP. Media can be specialized for industrial
applications.

Information: www.odva.org

## Network Comparisons

Tables 2 through 4 show the general information, physical
characteristics, and transport mechanism of specific standards covered
in this document. These tables were produced using published vendor
documents and information from various vendor websites. See also:

-   http://www.synergetic.com/compare.htm

-   http://www.ibsclub.com/whyibus/comparisons

-   http://www.sercos.com/comparisons.htm

-   http://www.seriplex.org/part4/wp.html#table2

Table 2. Background Information

+-----------+--------------+----------+------------------------------+
|           | *            | **Go     | **Websites**                 |
|           | *Technology\ | verning\ |                              |
|           | Developer\   | St       |                              |
|           | or\          | andard** |                              |
|           | User's       |          |                              |
|           | Group**      |          |                              |
+-----------+--------------+----------+------------------------------+
| AS-I      | AS-I         | EN 50295 | www.as-interface.com         |
|           | Consortium   |          |                              |
+-----------+--------------+----------+------------------------------+
| DeviceNet | Open         | ISO      | www.odva.org                 |
|           | DeviceNet    | 11898 &  |                              |
|           | Vendor       | 11519    |                              |
|           | Association, |          |                              |
|           | Inc. (ODVA)  |          |                              |
+-----------+--------------+----------+------------------------------+
| Ethernet  | Gigabit      | IEEE     | \- www.gigabit-ethernet.org  |
|           | Ethernet     | 802.3    |                              |
|           | Alliance,    |          | \-                           |
|           |              |          | www.ietf.cnri.reston.va.us   |
|           | Internet     |          |                              |
|           | Engineering  |          | \- ieee802.org               |
|           | Task Force   |          |                              |
|           |              |          | \-                           |
|           | IEEE 802     |          | www.industrialethernet.org   |
|           | LAN/MAN      |          |                              |
|           | Standards    |          |                              |
|           | Committee    |          |                              |
|           |              |          |                              |
|           | Industrial   |          |                              |
|           | Ethernet     |          |                              |
|           | Association  |          |                              |
+-----------+--------------+----------+------------------------------+
| Fieldbus  | Fieldbus     | IEC      | www.iec.ch,                  |
| F         | Foundation   | 61158    |                              |
| oundation |              | ANSI/I   | www.fieldbus.org,            |
| H1        |              | SA-50.02 |                              |
|           |              |          | www.isa.o                    |
|           |              |          | rg/portals/fieldbus/fbstand/ |
+-----------+--------------+----------+------------------------------+
| Fieldbus  | Fieldbus     | IEC      | www.iec.ch,                  |
| Fo        | Foundation   | 61158    |                              |
| undation\ |              | ANSI/I   | www.fieldbus.org,            |
| High      |              | SA-50.02 |                              |
| Speed     |              |          | www.isa.o                    |
| Ethernet  |              |          | rg/portals/fieldbus/fbstand/ |
| (HSE)     |              |          |                              |
+-----------+--------------+----------+------------------------------+
| Firewire  | 1394 Trade   | I        | www.1394ta.org               |
|           | Association  | EEE-1394 |                              |
+-----------+--------------+----------+------------------------------+
| Interbus  | Phoenix      | EN50254  | www.interbus.com             |
|           | Contact      |          |                              |
|           |              |          | www.ibsclub.com              |
+-----------+--------------+----------+------------------------------+
| Macro     | Delta Tau    | None     | www.macro.org                |
+-----------+--------------+----------+------------------------------+
| Profibus\ | Profibus     | DIN      | www.profibus.com             |
| DP/PA     | User Group   | 19245    |                              |
|           |              | part 3/4 |                              |
+-----------+--------------+----------+------------------------------+
| Profibus\ | Profibus     | EN 50    | www.profibus.com             |
| FMS       | User Group   | 170      |                              |
|           |              |          |                              |
|           |              | Volume 2 |                              |
+-----------+--------------+----------+------------------------------+
| ProfiNet  | Profibus     |          | www.profibus.com             |
|           | User Group   |          |                              |
+-----------+--------------+----------+------------------------------+
| SDS       | Honeywell    | H        | content.honeywe              |
|           |              | oneywell | ll.com/sensing/prodinfo/sds/ |
|           |              | Specif   |                              |
|           |              | ication, |                              |
|           |              | S        |                              |
|           |              | ubmitted |                              |
|           |              | to IEC,  |                              |
|           |              | ISO11989 |                              |
+-----------+--------------+----------+------------------------------+
| SERCOS    | SERCOS       | IEC      | www.sercos.com               |
|           | Interface    | 61491    |                              |
|           | Association  | /EN61491 |                              |
|           | (IGS) and    |          |                              |
|           | SERCOS North |          |                              |
|           | America      |          |                              |
+-----------+--------------+----------+------------------------------+
| Seriplex  | SERIPLEX     | IEC      | www.seriplex.org             |
|           | Technology   | 6        |                              |
|           | Orga         | 2026/6,\ |                              |
|           | nizationAPC, | SEMI     |                              |
|           | Inc.         | E54.7    |                              |
+-----------+--------------+----------+------------------------------+
|           |              |          |                              |
+-----------+--------------+----------+------------------------------+

*.*

Table 3 Physical Characteristics

+--------+----------------+----------+-----------+-------------------+
|        | **Network\     | **P      | **Max.    | **Max.\           |
|        | Topology**     | hysical\ | Devices\  | Distance**        |
|        |                | Media**  | (nodes)** |                   |
+--------+----------------+----------+-----------+-------------------+
| AS-I   | Bus, ring,     | Two wire | 31 slaves | 100 meters, 300   |
|        | tree star      | cable    |           | with repeater     |
+--------+----------------+----------+-----------+-------------------+
| Dev    | Trun           | Twis     | 64 nodes  | 500m              |
| iceNet | kline/dropline | ted-pair |           |                   |
|        | with branching | for      |           |                   |
|        |                | signal & |           |                   |
|        |                | power    |           |                   |
+--------+----------------+----------+-----------+-------------------+
| Et     | <table>        |          |           |                   |
| hernet | <colgroup>     |          |           |                   |
|        | <col           |          |           |                   |
|        | style="        |          |           |                   |
|        | width: 12%" /> |          |           |                   |
|        | <col           |          |           |                   |
|        | style="        |          |           |                   |
|        | width: 10%" /> |          |           |                   |
|        | <col           |          |           |                   |
|        | style="        |          |           |                   |
|        | width: 10%" /> |          |           |                   |
|        | <col           |          |           |                   |
|        | style=         |          |           |                   |
|        | "width: 9%" /> |          |           |                   |
|        | <col           |          |           |                   |
|        | style=         |          |           |                   |
|        | "width: 0%" /> |          |           |                   |
|        | <col           |          |           |                   |
|        | style="        |          |           |                   |
|        | width: 34%" /> |          |           |                   |
|        | <col           |          |           |                   |
|        | style=         |          |           |                   |
|        | "width: 1%" /> |          |           |                   |
|        | <col           |          |           |                   |
|        | style=         |          |           |                   |
|        | "width: 8%" /> |          |           |                   |
|        | <col           |          |           |                   |
|        | style="        |          |           |                   |
|        | width: 13%" /> |          |           |                   |
|        | </colgroup>    |          |           |                   |
|        | <tbody>        |          |           |                   |
|        | <tr            |          |           |                   |
|        | class="odd">   |          |           |                   |
|        | <td            |          |           |                   |
|        | >Standard</td> |          |           |                   |
|        | <              |          |           |                   |
|        | td><p>Data</p> |          |           |                   |
|        | <p             |          |           |                   |
|        | >Rate</p></td> |          |           |                   |
|        | <td>Network    |          |           |                   |
|        | Topology</td>  |          |           |                   |
|        | <td>Max.       |          |           |                   |
|        | Devices</td>   |          |           |                   |
|        | <td            |          |           |                   |
|        | colspan="2">   |          |           |                   |
|        | Physical<br /> |          |           |                   |
|        | Media</td>     |          |           |                   |
|        | <td            |          |           |                   |
|        | colsp          |          |           |                   |
|        | an="3">Maximum |          |           |                   |
|        | Cable          |          |           |                   |
|        | Segment<br />  |          |           |                   |
|        | Length in      |          |           |                   |
|        | Meters</td>    |          |           |                   |
|        | </tr>          |          |           |                   |
|        | <tr            |          |           |                   |
|        | class="even">  |          |           |                   |
|        | <td></td>      |          |           |                   |
|        | <td></td>      |          |           |                   |
|        | <td></td>      |          |           |                   |
|        | <td></td>      |          |           |                   |
|        | <td            |          |           |                   |
|        | col            |          |           |                   |
|        | span="2"></td> |          |           |                   |
|        | <td            |          |           |                   |
|        | colsp          |          |           |                   |
|        | an="3"><table> |          |           |                   |
|        | <colgroup>     |          |           |                   |
|        | <col           |          |           |                   |
|        | style="        |          |           |                   |
|        | width: 50%" /> |          |           |                   |
|        | <col           |          |           |                   |
|        | style="        |          |           |                   |
|        | width: 49%" /> |          |           |                   |
|        | </colgroup>    |          |           |                   |
|        | <tbody>        |          |           |                   |
|        | <tr            |          |           |                   |
|        | class="odd">   |          |           |                   |
|        | <td>Ha         |          |           |                   |
|        | lf-Duplex</td> |          |           |                   |
|        | <td>Fu         |          |           |                   |
|        | ll-Duplex</td> |          |           |                   |
|        | </tr>          |          |           |                   |
|        | </tbody>       |          |           |                   |
|        | </table></td>  |          |           |                   |
|        | </tr>          |          |           |                   |
|        | <tr            |          |           |                   |
|        | class="odd">   |          |           |                   |
|        | <t             |          |           |                   |
|        | d>10Base5</td> |          |           |                   |
|        | <              |          |           |                   |
|        | td>10Mb/s</td> |          |           |                   |
|        | <td>Bus</td>   |          |           |                   |
|        | <td>100</td>   |          |           |                   |
|        | <td            |          |           |                   |
|        | cols           |          |           |                   |
|        | pan="2">50-ohm |          |           |                   |
|        | coaxial        |          |           |                   |
|        | cable -thick   |          |           |                   |
|        | Ethernet</td>  |          |           |                   |
|        | <td            |          |           |                   |
|        | colspa         |          |           |                   |
|        | n="2">500</td> |          |           |                   |
|        | <td>n/a</td>   |          |           |                   |
|        | </tr>          |          |           |                   |
|        | <tr            |          |           |                   |
|        | class="even">  |          |           |                   |
|        | <t             |          |           |                   |
|        | d>10Base2</td> |          |           |                   |
|        | <              |          |           |                   |
|        | td>10Mb/s</td> |          |           |                   |
|        | <td>Bus</td>   |          |           |                   |
|        | <td>30</td>    |          |           |                   |
|        | <td            |          |           |                   |
|        | cols           |          |           |                   |
|        | pan="2">single |          |           |                   |
|        | 50-ohm RG 58   |          |           |                   |
|        | coaxial        |          |           |                   |
|        | cable (thin    |          |           |                   |
|        | Ethernet)      |          |           |                   |
|        | (5mm           |          |           |                   |
|        | thick)</td>    |          |           |                   |
|        | <td            |          |           |                   |
|        | colspa         |          |           |                   |
|        | n="2">185</td> |          |           |                   |
|        | <td>n/a</td>   |          |           |                   |
|        | </tr>          |          |           |                   |
|        | <tr            |          |           |                   |
|        | class="odd">   |          |           |                   |
|        | <td>           |          |           |                   |
|        | 10Broad36</td> |          |           |                   |
|        | <              |          |           |                   |
|        | td>10Mb/s</td> |          |           |                   |
|        | <td>Bus</td>   |          |           |                   |
|        | <td>1024</td>  |          |           |                   |
|        | <td            |          |           |                   |
|        | cols           |          |           |                   |
|        | pan="2">single |          |           |                   |
|        | 75-ohm CATV    |          |           |                   |
|        | broadband      |          |           |                   |
|        | cable</td>     |          |           |                   |
|        | <td            |          |           |                   |
|        | colspan        |          |           |                   |
|        | ="2">1800</td> |          |           |                   |
|        | <td>n/a</td>   |          |           |                   |
|        | </tr>          |          |           |                   |
|        | <tr            |          |           |                   |
|        | class="even">  |          |           |                   |
|        | <td>FOIRL</td> |          |           |                   |
|        | <              |          |           |                   |
|        | td>10Mb/s</td> |          |           |                   |
|        | <td>Star</td>  |          |           |                   |
|        | <td>1024</td>  |          |           |                   |
|        | <td            |          |           |                   |
|        | c              |          |           |                   |
|        | olspan="2">two |          |           |                   |
|        | optical        |          |           |                   |
|        | fibers</td>    |          |           |                   |
|        | <td            |          |           |                   |
|        | colspan        |          |           |                   |
|        | ="2">1000</td> |          |           |                   |
|        | <td            |          |           |                   |
|        | >&gt;1000</td> |          |           |                   |
|        | </tr>          |          |           |                   |
|        | <tr            |          |           |                   |
|        | class="odd">   |          |           |                   |
|        | <              |          |           |                   |
|        | td>1Base5</td> |          |           |                   |
|        | <td>1Mb/s</td> |          |           |                   |
|        | <td>Star</td>  |          |           |                   |
|        | <td>1024</td>  |          |           |                   |
|        | <td            |          |           |                   |
|        | c              |          |           |                   |
|        | olspan="2">two |          |           |                   |
|        | pairs of       |          |           |                   |
|        | twisted        |          |           |                   |
|        | telephone      |          |           |                   |
|        | cable</td>     |          |           |                   |
|        | <td            |          |           |                   |
|        | colspa         |          |           |                   |
|        | n="2">250</td> |          |           |                   |
|        | <td>n/a</td>   |          |           |                   |
|        | </tr>          |          |           |                   |
|        | <tr            |          |           |                   |
|        | class="even">  |          |           |                   |
|        | <td            |          |           |                   |
|        | >10Base-T</td> |          |           |                   |
|        | <              |          |           |                   |
|        | td>10Mb/s</td> |          |           |                   |
|        | <td>Star</td>  |          |           |                   |
|        | <td>1024</td>  |          |           |                   |
|        | <td            |          |           |                   |
|        | c              |          |           |                   |
|        | olspan="2">two |          |           |                   |
|        | pairs of       |          |           |                   |
|        | 100-ohm        |          |           |                   |
|        | Category 3     |          |           |                   |
|        | or better      |          |           |                   |
|        | UTP            |          |           |                   |
|        | cable</td>     |          |           |                   |
|        | <td            |          |           |                   |
|        | colspa         |          |           |                   |
|        | n="2">100</td> |          |           |                   |
|        | <td>100</td>   |          |           |                   |
|        | </tr>          |          |           |                   |
|        | <tr            |          |           |                   |
|        | class="odd">   |          |           |                   |
|        | <td>           |          |           |                   |
|        | 10Base-FL</td> |          |           |                   |
|        | <              |          |           |                   |
|        | td>10Mb/s</td> |          |           |                   |
|        | <td>Star</td>  |          |           |                   |
|        | <td>1024</td>  |          |           |                   |
|        | <td            |          |           |                   |
|        | c              |          |           |                   |
|        | olspan="2">two |          |           |                   |
|        | optical        |          |           |                   |
|        | fibers</td>    |          |           |                   |
|        | <td            |          |           |                   |
|        | colspan        |          |           |                   |
|        | ="2">2000</td> |          |           |                   |
|        | <td            |          |           |                   |
|        | >&gt;2000</td> |          |           |                   |
|        | </tr>          |          |           |                   |
|        | <tr            |          |           |                   |
|        | class="even">  |          |           |                   |
|        | <td>           |          |           |                   |
|        | 10Base-FB</td> |          |           |                   |
|        | <              |          |           |                   |
|        | td>10Mb/s</td> |          |           |                   |
|        | <td>Star</td>  |          |           |                   |
|        | <td>1024</td>  |          |           |                   |
|        | <td            |          |           |                   |
|        | c              |          |           |                   |
|        | olspan="2">two |          |           |                   |
|        | optical        |          |           |                   |
|        | fibers</td>    |          |           |                   |
|        | <td            |          |           |                   |
|        | colspan        |          |           |                   |
|        | ="2">2000</td> |          |           |                   |
|        | <td>n/a</td>   |          |           |                   |
|        | </tr>          |          |           |                   |
|        | <tr            |          |           |                   |
|        | class="odd">   |          |           |                   |
|        | <td>           |          |           |                   |
|        | 10Base-FP</td> |          |           |                   |
|        | <              |          |           |                   |
|        | td>10Mb/s</td> |          |           |                   |
|        | <td>Star</td>  |          |           |                   |
|        | <td>1024</td>  |          |           |                   |
|        | <td            |          |           |                   |
|        | c              |          |           |                   |
|        | olspan="2">two |          |           |                   |
|        | optical        |          |           |                   |
|        | fibers</td>    |          |           |                   |
|        | <td            |          |           |                   |
|        | colspan        |          |           |                   |
|        | ="2">1000</td> |          |           |                   |
|        | <td>n/a</td>   |          |           |                   |
|        | </tr>          |          |           |                   |
|        | <tr            |          |           |                   |
|        | class="even">  |          |           |                   |
|        | <td>1          |          |           |                   |
|        | 00Base-TX</td> |          |           |                   |
|        | <t             |          |           |                   |
|        | d>100Mb/s</td> |          |           |                   |
|        | <td>Star</td>  |          |           |                   |
|        | <td>1024</td>  |          |           |                   |
|        | <td            |          |           |                   |
|        | c              |          |           |                   |
|        | olspan="2">two |          |           |                   |
|        | pairs of       |          |           |                   |
|        | 100-ohm        |          |           |                   |
|        | Category 5     |          |           |                   |
|        | UTP            |          |           |                   |
|        | cable</td>     |          |           |                   |
|        | <td            |          |           |                   |
|        | colspa         |          |           |                   |
|        | n="2">100</td> |          |           |                   |
|        | <td>100</td>   |          |           |                   |
|        | </tr>          |          |           |                   |
|        | <tr            |          |           |                   |
|        | class="odd">   |          |           |                   |
|        | <td>1          |          |           |                   |
|        | 00Base-FX</td> |          |           |                   |
|        | <t             |          |           |                   |
|        | d>100Mb/s</td> |          |           |                   |
|        | <td>Star</td>  |          |           |                   |
|        | <td>1024</td>  |          |           |                   |
|        | <td            |          |           |                   |
|        | c              |          |           |                   |
|        | olspan="2">two |          |           |                   |
|        | optical        |          |           |                   |
|        | fibers</td>    |          |           |                   |
|        | <td            |          |           |                   |
|        | colspa         |          |           |                   |
|        | n="2">412</td> |          |           |                   |
|        | <td>2000</td>  |          |           |                   |
|        | </tr>          |          |           |                   |
|        | <tr            |          |           |                   |
|        | class="even">  |          |           |                   |
|        | <td>1          |          |           |                   |
|        | 00Base-T4</td> |          |           |                   |
|        | <t             |          |           |                   |
|        | d>100Mb/s</td> |          |           |                   |
|        | <td>Star</td>  |          |           |                   |
|        | <td>1024</td>  |          |           |                   |
|        | <td            |          |           |                   |
|        | co             |          |           |                   |
|        | lspan="2">four |          |           |                   |
|        | pairs of       |          |           |                   |
|        | 100-ohm        |          |           |                   |
|        | Category 3     |          |           |                   |
|        | or better      |          |           |                   |
|        | UTP            |          |           |                   |
|        | cable</td>     |          |           |                   |
|        | <td            |          |           |                   |
|        | colspa         |          |           |                   |
|        | n="2">100</td> |          |           |                   |
|        | <td>n/a</td>   |          |           |                   |
|        | </tr>          |          |           |                   |
|        | <tr            |          |           |                   |
|        | class="odd">   |          |           |                   |
|        | <td>1          |          |           |                   |
|        | 00Base-T2</td> |          |           |                   |
|        | <t             |          |           |                   |
|        | d>100Mb/s</td> |          |           |                   |
|        | <td>Star</td>  |          |           |                   |
|        | <td>1024</td>  |          |           |                   |
|        | <td            |          |           |                   |
|        | c              |          |           |                   |
|        | olspan="2">two |          |           |                   |
|        | pairs of       |          |           |                   |
|        | 100-ohm        |          |           |                   |
|        | Category 3     |          |           |                   |
|        | or better      |          |           |                   |
|        | UTP            |          |           |                   |
|        | cable</td>     |          |           |                   |
|        | <td            |          |           |                   |
|        | colspa         |          |           |                   |
|        | n="2">100</td> |          |           |                   |
|        | <td>100</td>   |          |           |                   |
|        | </tr>          |          |           |                   |
|        | <tr            |          |           |                   |
|        | class="even">  |          |           |                   |
|        | <td>10         |          |           |                   |
|        | 00Base-LX</td> |          |           |                   |
|        | <td>1Gb/s</td> |          |           |                   |
|        | <td>Star</td>  |          |           |                   |
|        | <td>1024</td>  |          |           |                   |
|        | <td            |          |           |                   |
|        | co             |          |           |                   |
|        | lspan="2">long |          |           |                   |
|        | wavelength     |          |           |                   |
|        | laser          |          |           |                   |
|        | over:<br />    |          |           |                   |
|        | - 62.5um       |          |           |                   |
|        | multi-mode     |          |           |                   |
|        | fiber<br />    |          |           |                   |
|        | - 50um         |          |           |                   |
|        | multi-mode     |          |           |                   |
|        | fiber<br />    |          |           |                   |
|        | - 10um         |          |           |                   |
|        | single mode    |          |           |                   |
|        | fiber</td>     |          |           |                   |
|        | <td            |          |           |                   |
|        | colspan        |          |           |                   |
|        | ="2">316<br /> |          |           |                   |
|        | 316<br />      |          |           |                   |
|        | 316</td>       |          |           |                   |
|        | <td>550<br />  |          |           |                   |
|        | 550<br />      |          |           |                   |
|        | 5000</td>      |          |           |                   |
|        | </tr>          |          |           |                   |
|        | <tr            |          |           |                   |
|        | class="odd">   |          |           |                   |
|        | <td>10         |          |           |                   |
|        | 00Base-SX</td> |          |           |                   |
|        | <td>1Gb/s</td> |          |           |                   |
|        | <td>Star</td>  |          |           |                   |
|        | <td            |          |           |                   |
|        | colspan        |          |           |                   |
|        | ="2">1024</td> |          |           |                   |
|        | <td            |          |           |                   |
|        | col            |          |           |                   |
|        | span="2">short |          |           |                   |
|        | wavelength     |          |           |                   |
|        | laser          |          |           |                   |
|        | (850nm)        |          |           |                   |
|        | over:<br />    |          |           |                   |
|        | - 62.5um       |          |           |                   |
|        | multi-mode     |          |           |                   |
|        | fiber<br />    |          |           |                   |
|        | - 50um         |          |           |                   |
|        | multi-mode     |          |           |                   |
|        | fiber</td>     |          |           |                   |
|        | <td>275<br />  |          |           |                   |
|        | 316</td>       |          |           |                   |
|        | <td>275<br />  |          |           |                   |
|        | 550</td>       |          |           |                   |
|        | </tr>          |          |           |                   |
|        | <tr            |          |           |                   |
|        | class="even">  |          |           |                   |
|        | <td>10         |          |           |                   |
|        | 00Base-CX</td> |          |           |                   |
|        | <td>1Gb/s</td> |          |           |                   |
|        | <td>Star</td>  |          |           |                   |
|        | <td            |          |           |                   |
|        | col            |          |           |                   |
|        | span="2"></td> |          |           |                   |
|        | <td            |          |           |                   |
|        | colspan        |          |           |                   |
|        | ="2">specialty |          |           |                   |
|        | shielded       |          |           |                   |
|        | balanced       |          |           |                   |
|        | copper         |          |           |                   |
|        | jumper cable   |          |           |                   |
|        | assemblies     |          |           |                   |
|        | ("twinax" or   |          |           |                   |
|        | "short haul    |          |           |                   |
|        | copper")</td>  |          |           |                   |
|        | <td>25</td>    |          |           |                   |
|        | <td>25</td>    |          |           |                   |
|        | </tr>          |          |           |                   |
|        | <tr            |          |           |                   |
|        | class="odd">   |          |           |                   |
|        | <td>1          |          |           |                   |
|        | 000Base-T</td> |          |           |                   |
|        | <td>1Gb/s</td> |          |           |                   |
|        | <td>Star</td>  |          |           |                   |
|        | <td            |          |           |                   |
|        | col            |          |           |                   |
|        | span="2"></td> |          |           |                   |
|        | <td            |          |           |                   |
|        | co             |          |           |                   |
|        | lspan="2">four |          |           |                   |
|        | pairs of       |          |           |                   |
|        | 100-ohm        |          |           |                   |
|        | Category 5     |          |           |                   |
|        | or better      |          |           |                   |
|        | cable</td>     |          |           |                   |
|        | <td>100</td>   |          |           |                   |
|        | <td>100</td>   |          |           |                   |
|        | </tr>          |          |           |                   |
|        | </tbody>       |          |           |                   |
|        | </table>       |          |           |                   |
+--------+----------------+----------+-----------+-------------------+
| Fi     | Multidrop with | Twis     | 240       | 1900m @ 31.25K    |
| eldbus | bus powered    | ted-pair | /segment, | 500m @ 2.5M       |
| Foun   | devices        |          | 65,000    |                   |
| dation |                |          | segments  |                   |
| H1     |                |          |           |                   |
+--------+----------------+----------+-----------+-------------------+
| Foun   | Star           | Twist    | IP        | 100m @ 100Mbaud   |
| dation |                | ed-pair, | add       | twisted-pair      |
| Fi     |                | fiber    | ressing - |                   |
| eldbus |                |          | es        | 2000m @ 100Mbaud  |
| HSE    |                |          | sentially | fiber full duplex |
|        |                |          | unlimited |                   |
+--------+----------------+----------+-----------+-------------------+
| Fi     | No-loops Tree  | 6-wire   | c         | total maximum     |
| rewire |                | shielded | apability | end-to-end        |
|        |                | twisted  | to        | distance of 72m   |
|        |                | pair     | address   |                   |
|        |                | copper - | 1023      |                   |
|        |                |          | networks  |                   |
|        |                |          | of 63     |                   |
|        |                |          | nodes,    |                   |
|        |                |          | each with |                   |
|        |                |          | 281       |                   |
|        |                |          | terabytes |                   |
|        |                |          | of memory |                   |
+--------+----------------+----------+-----------+-------------------+
| In     | Bus,Tree,      | Twist    | 512       | 12.8 Km (copper)  |
| terbus | Ring, Star, 16 | ed-pair, | System    | total\            |
|        | level nesting  | fiber,   | Total\    | 400m max between  |
|        |                | sl       | 256 on    | devices           |
|        |                | ip-ring, | remote    |                   |
|        |                | Infrared | bus       |                   |
+--------+----------------+----------+-----------+-------------------+
| Macro  | Ring based on  | Fiber    | 256 \--   | Glass \-- 3000 m  |
|        | FDDI (Fiber    | optic,   | Supports  |                   |
|        | Direct Digital | coax, or | up to 16  | Copper \-- 30 m   |
|        | Interface)     | RJ-45    | masters,  |                   |
|        | networking     |          | with up   |                   |
|        | technology     |          | to 16     |                   |
|        |                |          | nodes     |                   |
|        |                |          | i         |                   |
|        |                |          | nterfaced |                   |
|        |                |          | per       |                   |
|        |                |          | master    |                   |
+--------+----------------+----------+-----------+-------------------+
| Pr     | Line, star &   | Twis     | 127 nodes | 24 Km (fiber)     |
| ofibus | ring           | ted-pair |           |                   |
| DP/PA  |                | or fiber |           |                   |
+--------+----------------+----------+-----------+-------------------+
| Pr     | Line, star &   | Twis     | up to 126 |                   |
| ofibus | ring           | ted-pair | nodes are |                   |
| FMS    |                | or fiber | available |                   |
|        |                |          | and all   |                   |
|        |                |          | can be    |                   |
|        |                |          | masters   |                   |
|        |                |          | if        |                   |
|        |                |          | desired   |                   |
+--------+----------------+----------+-----------+-------------------+
| SDS    | Trun           | Twis     | 64 nodes, | 500m              |
|        | kline/Dropline | ted-pair | 126       |                   |
|        |                | for      | addresses |                   |
|        |                | signal & |           |                   |
|        |                | power    |           |                   |
+--------+----------------+----------+-----------+-------------------+
| SERCOS | Ring           | Fiber    | 254 per   | Plastic - 40 m    |
|        |                | optic    | ring,     | node-to-node;     |
|        |                |          | multiple  | 10,000+ m max.    |
|        |                |          | rings     | ring length.      |
|        |                |          | allowed   |                   |
|        |                |          |           | Glass - 800 m     |
|        |                |          |           | node-to-node;     |
|        |                |          |           | 200,000+ m max.   |
|        |                |          |           | ring length.      |
+--------+----------------+----------+-----------+-------------------+
| Se     | Tree, loop,    | 4-wire   | 500+      | 500+ ft.          |
| riplex | ring,          | shielded | devices   |                   |
|        | multi-drop,    | cable    |           |                   |
|        | star           |          |           |                   |
+--------+----------------+----------+-----------+-------------------+

Table 4 Transport Mechanisms

+----------+-------------------+--------------+-----------+----------+
|          | **Communication\  | **T          | **Data\   | **Arbi   |
|          | Method**          | ransmission\ | Transfer\ | tration\ |
|          |                   | Speed**      | Size**    | Method** |
+----------+-------------------+--------------+-----------+----------+
| AS-I     | Master/slave with | Data and     | 31 slaves | Mast     |
|          | cyclic polling    | power, EMI   | with 4 in | er/slave |
|          |                   | resistant    | and 4 out | with     |
|          |                   |              |           | cyclic   |
|          |                   |              |           | polling  |
+----------+-------------------+--------------+-----------+----------+
| Co       | Producer/Consumer | 5 Mbps       | 0-510     | CTDMA    |
| ntrolNet | Device Object     |              | bytes     | Time     |
|          | Model             |              | variable  | Slice    |
|          |                   |              |           | Multiple |
|          |                   |              |           | Access   |
|          |                   |              |           | M        |
|          |                   |              |           | odified, |
|          |                   |              |           | Device   |
+----------+-------------------+--------------+-----------+----------+
| D        | Master/slave,     | 500 kbps,    | 8-byte    | Carri    |
| eviceNet | multi-master,     | 250 kbps,    | variable  | er-Sonac |
|          | others            | 125 kbps     | message   | Multiple |
|          |                   |              |           | Access   |
+----------+-------------------+--------------+-----------+----------+
| Ethernet | Peer-to-peer,     | 10Mbps,      | Min: 128  | CSMA/CD  |
|          | Broadcast         | 100Mbps,     | bytes     |          |
|          |                   | 1000Mbps     |           |          |
|          |                   |              | Max: 1582 |          |
|          |                   |              | bytes     |          |
+----------+-------------------+--------------+-----------+----------+
| Fieldbus | Client/server     | 31.25 kbps 1 | 16.6 M    | Deter    |
| Fo       | publ              | Mbps\        | objec     | ministic |
| undation | isher/subscriber, | 2.5Mbps      | ts/device | cen      |
|          | Event             |              |           | tralized |
|          | notification      |              |           | sc       |
|          |                   |              |           | heduler, |
|          |                   |              |           | multiple |
|          |                   |              |           | backup   |
+----------+-------------------+--------------+-----------+----------+
| Firewire | Multi-master,     | 100, 200 and | Minimum   | reque    |
|          | Peer-to-peer,     | 400 Mbps     | -- 20     | st-grant |
|          | guaranteed and    | with         | bytes     | h        |
|          | deterministic     | 1394a-2000,  | header,   | andshake |
|          | bandwidth         | and up to    | "payload" | process  |
|          |                   | 3200Mbps     | extra     | between  |
|          |                   | with P1394b  |           | a node   |
|          |                   |              |           | and      |
|          |                   |              |           |          |
|          |                   |              |           | every    |
|          |                   |              |           | node in  |
|          |                   |              |           | the path |
|          |                   |              |           | up to    |
|          |                   |              |           | the root |
|          |                   |              |           | node to  |
|          |                   |              |           | win a    |
|          |                   |              |           | turn at  |
|          |                   |              |           | using    |
|          |                   |              |           | the bus  |
+----------+-------------------+--------------+-----------+----------+
| Interbus | Master/slave with | 500kBits/s,  | Up to:    | None     |
|          | total frame       | full duplex  |           |          |
|          | transfer          |              | 64bytes   |          |
|          |                   |              | real time |          |
|          | Transparent data  |              | data      |          |
|          | linking via       |              | /device,  |          |
|          | master            |              |           |          |
|          |                   |              | 244 Bytes |          |
|          |                   |              | PCP       |          |
|          |                   |              | da        |          |
|          |                   |              | ta/device |          |
|          |                   |              |           |          |
|          |                   |              | 512 In +  |          |
|          |                   |              | 512 Out   |          |
|          |                   |              | bytes per |          |
|          |                   |              | system    |          |
+----------+-------------------+--------------+-----------+----------+
| Macro    | Multi-master - up | 120          | Variable  | Shift    |
|          | to 16 per ring    | MBits/sec    | size      | register |
|          |                   |              |           | between  |
|          |                   |              |           | adjacent |
|          |                   |              |           | nodes    |
+----------+-------------------+--------------+-----------+----------+
| Profibus | Master/slave\     | DP up to 12  | 244 bytes | Token    |
| DP/PA    | peer to peer      | Mbps (it can |           | passing  |
|          |                   | also be      |           |          |
|          |                   | operated at  |           |          |
|          |                   | speeds as    |           |          |
|          |                   | low as 9600  |           |          |
|          |                   | baud)\       |           |          |
|          |                   | PA 31.25     |           |          |
|          |                   | kbps         |           |          |
+----------+-------------------+--------------+-----------+----------+
| Profibus | peer to peer      | Same as      | More      | Token    |
| FMS      | messaging format  | Profibus/DP  | overhead  | passing  |
+----------+-------------------+--------------+-----------+----------+
| SDS      | Master/slave,     | 1Mbps,\      | 8-byte    | Carri    |
|          | peer to peer,     | 500 kbps,\   | variable  | er-Sonac |
|          | multi-cast,       | 250 kbps,\   | message   | Multiple |
|          | multi-master      | 125 kbps     |           | Access   |
+----------+-------------------+--------------+-----------+----------+
| SERCOS   | Master/slaves     | 2/4/8/16     | Variable  | Deter    |
|          |                   | MBits/sec    | size,     | ministic |
|          |                   |              | Minimum   | time     |
|          |                   |              | Master    | slice,   |
|          |                   |              | Sync      | depends  |
|          |                   |              | T         | on the   |
|          |                   |              | elegram - | number   |
|          |                   |              | 6 bytes   | of nodes |
|          |                   |              |           | on the   |
|          |                   |              |           | ring.    |
+----------+-------------------+--------------+-----------+----------+
| Seriplex | Master/slave peer | 200 Mbps     | 7680      | Sonal    |
|          | to peer           |              | /transfer | mult     |
|          |                   |              |           | iplexing |
+----------+-------------------+--------------+-----------+----------+

# Conclusion

Market adoption of standards can greatly reduce development costs for
end-users, system integrators as well as vendors. For example, OLE for
Process Control (OPC) replaces custom drivers used to connect different
manufacturer's IO field device products. Before OPC, a different driver
was required to connect Intellution's FIX to Allen-Bradley PLCs, or
Siemens PLCs or GE Fanuc PLCs. At one time, Wonderware advertised over
200 such drivers. Now, one OPC driver is required to connect to any one
of these PLCs running an OPC server. Moreover, the Intellution FIX can
be replaced by a USDATA or Wonderware product as these conform to the
standard OPC client interface.

Ideally, one network standard would allow interoperable network
communication across the factory landscape, including continuous,
advanced, batch, discrete, and motion control as well as to the MRP.
Ethernet is emerging a single network backbone, however, the reality is
that application needs dictate different requirements and costs to
consider when designing a motion control system. Unfortunately,
standardization infighting between control system suppliers and field
device suppliers, when combined with standards imposed by territorial
domain, has lead to a wide variety of standards, as well as overlap and
ambiguity even within standards. Thus, users have more than a dozen
control, field and device network alternatives to consider when
designing motion control systems.

For networking of motion control devices, the decision of whether to use
a fieldbus, device network, or high-speed network, or some combination
depends on the application. If only loose coupling between axes is
required, a series of single-axis position drives connected via a
fieldbus is probably adequate. In a tightly-coupled, synchronized motion
application, a high-speed network such as MACRO or SERCOS must be
considered as field buses are too slow.

A final consideration when dealing with products based on open standard
technology is that anybody can manufacture products and claim
conformance to these standards. This does not guarantee that these
products comply with the standards unless the product undergoes tests
for conformance and interoperability compliance. Fortunately, most
standards have independent third-parties who perform product testing to
insure a product complies to the standard.

# Standards Glossary

ANSI American National Standards Institute

CEN European Committee for Standardization

CENELEC European Committee for Electrotechnical Standardization

DD BSI standards are designated with the prefix DD

DD 238 Foundation Fieldbus

DD 241 ControlNet

DIN Deutsches Institut für Normung is the German national standards body
that reports to CEN and CENELEC

DIN 19258 Interbus-S

DIN 19425 Profibus

EIA Electronics Industry Association

EN CEN and CENELEC standards are designated with the prefix EN

EN 50170 General purpose field communication systems. Includes P-Net,
Profibus-DP/FMS/PA, WorldFIP, Foundation Fieldbus, and ControlNet.

EN 50254 High-efficiency communication subsystem for small data
packages. Includes Interbus, Profibus-DP subset, and WorldFIP subset.

EN 50295 Low-voltage switchgear and controlgear- controller and device
interface systems- actuator sensor interface (AS-I).

EN 50325 Industrial communication subsystem based on ISO 11898 (CAN) for
controller-device interfaces. Includes DeviceNet and SDS.

EN 61491 SERCOS

IEC International Electrotechnical Commission

IEC 1158-2 Specification for intrinsically safe operation

IEC 61158 Digital data communications for measurement and control-
Fieldbus for use in industrial control systems

IEC 61491 SERCOS

IEC 62026 Control circuit devices and switching elements for low-voltage
switchgear and controlgear. Includes AS-I, DeviceNet, LonTalk, SDS, and
Seriplex.

IEC SC65C IEC Subcommittee responsible for IEC 61158 (Fieldbus).

IEEE 802.2 Ethernet

IEEE 802.3u Request for Change (RFC) for TCP/IP and UDP, in support of
Foundation Fieldbus HSE

ISA Instrumentation, Systems, and Automation Society

ISA SP50 ISA Subcommittee responsible for ANSI/ISA-S50.02 (Fieldbus).

ANSI/ISA-S50.02 Fieldbus Standard for use in Industrial Control Systems.
U. S. equivalent of ISO 61158.

ISO International Organization for Standardization

ISO 7498 Open Systems Interconnect (OSI) 7-layer model for communication

ISO 9506 Manufacturing Messaging Specification (MMS), used by
Profibus-FMS.

ISO 11519 DeviceNet

ISO 11898 Road vehicles- interchange of digital information- controller
area network (CAN) for high-speed communication. Defines physical and
transport layers. DeviceNet, SDS, and CANOpen add application layer.

### Acknowledgments

A special thanks goes to Bill Rippey for meticulously reviewing and
revising this document.

### Disclaimer

No approval or endorsement of any commercial product by the National
Institute of Standards and Technology is intended or implied. Certain
commercial equipment, instruments, or materials are identified in this
report in order to facilitate understanding. Such identification does
not imply recommendation or endorsement by the National Institute of
Standards and Technology, nor does it imply that the materials or
equipment identified are necessarily the best available for the purpose
mentioned.

This publication was prepared by United States Government employees as
part of their official duties and is, therefore, a work of the U.S.
Government and not subject to copyright.