EN 50170:1996/A3:2002

SLOVENSKI STANDARD
01-september-2002
General purpose field communication system
General purpose field communication system
Ta slovenski standard je istoveten z: EN 50170:1996/A3:2002
ICS:
35.100.01 Medsebojno povezovanje Open systems
odprtih sistemov na splošno interconnection in general
35.200 Vmesniška in povezovalna Interface and interconnection
oprema equipment
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD EN 50170/A3
NORME EUROPÉENNE
EUROPÄISCHE NORM May 2002
ICS 35.100.00; 35.200
English version
General purpose field communication system
This amendment A3 modifies the European Standard EN 50170:1996; it was approved by CENELEC on
2000-08-01. CENELEC members are bound to comply with the CEN/CENELEC Internal Regulations
which stipulate the conditions for giving this amendment the status of a national standard without any
alteration.
Up-to-date lists and bibliographical references concerning such national standards may be obtained on
application to the Central Secretariat or to any CENELEC member.
This amendment exists in one official version (English). A version in any other language made by
translation under the responsibility of a CENELEC member into its own language and notified to the
Central Secretariat has the same status as the official versions.
CENELEC members are the national electrotechnical committees of Austria, Belgium, Czech Republic,
Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Malta, Netherlands,
Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom.
CENELEC
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
Central Secretariat: rue de Stassart 35, B - 1050 Brussels
© 2002 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Ref. No. EN 50170:1996/A3:2002 E

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Foreword
This European Standard was prepared by the Technical Committee CENELEC TC65CX, Fieldbus.
EN 50170/A3 (ControlNet) is a serial communication system for communication between devices that wish to
exchange time critical application information in a deterministic and predictable manner. These devices include
simple I/O devices, such as sensors/actuators as well as complex control devices such as robots, programmable
logic controllers, welders, process controllers, etc.
The text of the draft was submitted to the Unique Acceptance Procedure and was approved by CENELEC as
amendment A3 to EN 50170:1996 on 2000-08-01.
The following dates were fixed:
- latest date by which the EN has to be implemented
at national level by publication of an identical national
standard or by endorsement (dop) 2002-11-01
- latest date by the national standards conflicting with
the EN have to be withdrawn (dow) 2003-08-01
General information on licensing and patents
CENELEC calls attention to the fact that patent rights are linked to EN 50170 Amendment A3 (ControlNet).
CENELEC takes no position concerning the evidence, validity and scope of this patent right. The following release
of rights was made available to BSI, the originating CENELEC National Committee. In this release of rights
EN 50170/A3 is referred to as “BSI DD241”:
Release of Rights for BS1 DD241 ControlNet
By Allen-Bradley Company, LLC.
Allen-Bradley (A-B) developed the ControlNet technology and created the specification (in collaboration with
other Parties) that has been submitted to BSI. Allen-Bradley has on an open basis provided this technology and the
related specification to the market via ControlNet International and supports its acceptance by CENELEC as an
open communications Standard.
BSI has published ControlNet as BSI DD 241 and submitted it to CENELEC for consideration as a European
Standard.
There are seven (7) Allen-Bradley US Patents tied to the technology utilised in ControlNet. These Patents, which
are used to develop compliant products and Systems, are listed below (Note: A summary of each is available at
CENELEC).
1. 5,396,197 Network Node Tap
2. 5,400,331 Communication Network Interface With Screeners for Incoming Messages
3. 5,491,531Media Access Controller For A Station On a Communication Network
4. 5,471,461 Digital Communication Network With a Moderator Station Election Process
5. 5,493,571 Digital Communication Network Data Transmission Method and Apparatus
6. 5,537,549 Communication Network with Time Coordinated Station Activity
7. 5,553,095 Method and Apparatus for Exchanging Different Classes of Data During Time Intervals

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A-B is providing BSI, CENELEC and users of the Specification the rights to develop, manufacture, market and use
products that meet the specification and utilise A-B patented technology. This part of the grant of rights is
effectively a royalty-free license to developers and users of products which incorporate the communication
technology specified in BSI DD 241 to use the 7 US patents listed above in BS1 DD 241 compliant products.
Standardisation promotes interoperability, reduces costs to the end user and simplifies System and product
integration. As a result, the license granted to users of this technology requires users of the license to:
� Develop product which conforms to the specification
� Test for compliance to the specification
� Provide documentation to the user including a Statement of compliance to the specification
A-B has attempted to test the technology as completely as is practical. The specification is written based on A-B’s
own technology and experience of A-B’s own developers as well as developer’s from other companies working for
A-B. Every reasonable effort has been made to ensure that both the technology and the specification are: accurate
and complete, but in accordance with accepted practice it is not possible to provide a warranty to users of the
technology.
Realistically if errors are discovered or extensions requested, then it may he appropriate for changes to be made to
the specification. it is expected that change requests and incorporation of the technology tied to the changes could
occur in two ways.
� The first Option is that the issue would be raised in ControlNet International, the users‘ organization that
supports the marketing and continued development of this technology Special interest groups are organized to
manage the technology and would propose the modifications to CENELEC through a national standards
committee. This is similar to the process that has been followed by other networks.
� The second Option is that CENELEC/TC 65CX would establish a working group to address the need, develop
the technology and propose changes to the specification as appropriate.
A-B conducted searches of the prior art to uncover background technology both prior to applying for the patents
listed above and more recently over the last three months at the request of CENELEC TC 6SCX and based on.
those searches, the art uncovered by the US Patent Office, and A-B’s current knowledge of this field, A-B believes
the technology represented by the patents is novel. Further, A-B is not currently aware of any claims or
infringement of any valid intellectual property rights by any other companies relating to the technology described
in the Specification that could materially affect the use of the technology.
If during the application of those Standards Intellectual Property Rights may appear and will not be made available
on reasonable and non discriminatory terms and conditions to anyone wishing to obtain such a license, applying
the rules of CEN/CENELEC Memorandum 8, this fact shall be brought to the attention of CENELEC Central
Secretariat for further action.

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Contents for EN 50170/A3 Page
Part 1 General description.5
Part 2 Physical layer and media.15
Part 3 Data link layer .55
Part 4 Network and transport layer. 113
Part 5 Data management. 249
Part 6 Station management . 277
Part 7 Communication services . 309
Part 8 Communication objects. 349

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EN 50170:1996/A3-1:2002
General Purpose
Field Communication System
Part 1
General Description
of EN 50170/A3
Page 6
EN 50170:1996/A3-1:2002
Contents
1 Scope . 7
2 Normative references . 7
3 Definitions. 7
4 Abbreviations. 12
Annex A (informative) Bibliography . 14
General Description of EN 50170, Amendment A3
This description provides an overview on the models, services and characteristics of EN 50170 Amendment A3
(EN 50170/A3), also known under the name „ControlNet“.
“ControlNet” is the trade name of ControlNet International, an independent organisation of users and vendors of
ControlNet products. This information is given for the convenience of users of this pre-standard and does not
constitute an endorsement by CENELEC of the trade name mentioned. Equivalent products may be used if they
can be shown to lead to the same results.
EN 50170/A3 is a serial communication system for communication between devices that wish to exchange time
critical application information in a deterministic and predictable manner. These devices include simple I/O
devices, such as sensors/actuators as well as complex control devices such as robots, programmable logic
controllers, welders, process controllers, etc.
EN 50170/A3 relies on the destination delivery model, and uses the producer/consumer model (also known as
publisher/subscriber model). The producer/consumer model allows the exchange of time critical application
information between a sending device (i.e. the producer) and many receiving devices (i.e. the consumers) without
the need to send the data separately to each destination. This is accomplished by attaching a unique identifier to
each piece of application information that is being produced onto the network medium. Any device that requires a
specific piece of application information simply filters the data on the network medium for the appropriate
identifier. Many devices can receive the same piece of application information from a single producing device.
EN 50170/A3 (deterministic control network) provides a high degree of protocol efficiency by utilising an implied
token passing mechanism. This mechanism allows all devices equal access to the network without the network
overhead associated with passing a “token” to each device granting it permission to send data. The protocol
utilises a time based scheduling mechanism which provides network devices with deterministic and predictable
access to the medium while preventing network collisions. This scheduling mechanism allows time critical data,
which is required on a periodic, repeatable and predictable basis, to be produced on a predefined schedule without
the loss of efficiency associated with continuously requesting or “polling” for the required data.
The network protocol supports an additional mechanism which allows data that is not time critical in nature or
which is only required on an occasional basis to utilise any available network time. This unscheduled data is
transmitted after the production of the time critical data has been completed and before the beginning of the next
scheduled production of time critical data.

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EN 50170:1996/A3-1:2002
1 Scope
This part defines the requirements for the general description of a device on the network of EN 50170/A3
(deterministic control network).
Each of the other parts of EN 50170/A3 corresponds to a specific layer of the seven layer OSI model in accordance
with EN ISO/IEC 7498-1. Figure 1 shows the location of each part within the OSI model.
Control Network Layers
OSI Reference Model Layers
Communication
Application Parts 7, 8
Layer 7
Objects & Services
Data Management
Presentation Part 5
Layer 6
Null
Session
Null
Layer 5
Message Router
Transport
Layer 4
Transport
Part 4
Connection Manager
Network
Layer 3
LLC
Data Link
Layer 2
Part 3 Part 6: Station
MAC
Management
PLS
Layer 1 Physical
Part 2
PMA
Medium
Figure 1 - Relationship of parts 1 to 8 to the ISO/OSI model
2 Normative references
EN ISO/IEC 7498-1:1995 Information processing systems — Open systems interconnection — Basic reference model —
The basic model
3 Definitions
For the purposes of EN 50170/A3 the following definitions apply.
3.1 actual packet
The measure of how frequently a specific connection produces its data.
interval (API)
3.2 allocate
To take a resource from a common area and assign that resource for the exclusive
use of a specific entity.
3.3 application
Function or data structure for which data is consumed or produced.
3.4 applic
...