ISO 16484-5:2014

INTERNATIONAL ISO
STANDARD 16484-5
Fifth edition
2014‐05‐15

Building automation and control systems
(BACS) —

Part 5:
Data communication protocol
Systèmes d'automatisation et de gestion technique du bâtiment —
Partie 5: Protocole de communication de données




Reference number
ISO 16484‐5:2014(E)
©
ISO2014

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ISO 16484-5:2014(E)

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© ISO 2014 – All rights reserved
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ISO 16484-5:2014(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non‐governmental, in liaison with ISO, also take part in the work. ISO
collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2. www.iso.org/directives
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of any
patent rights identified during the development of the document will be in the Introduction and/or on the
ISO list of patent declarations received. www.iso.org/patents
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on the meaning of ISO specific terms and expressions related to conformity assessment,
as well as information about ISO's adherence to the WTO principles in the Technical
Barriers to Trade (TBT) see the following URL: Foreword ‐ Supplementary information
The committee responsible for this document is ISO/TC 205, Building environment design.
This fifth edition cancels and replaces the fourth edition (ISO 16484‐5:2012), of which it forms the subject
of a minor revision.
ISO 16484 consists of the following parts, under the general title Building automation and control systems
(BACS) — Data communication conformance testing:
— Part 1: Project specification and implementation
— Part 2: Hardware
— Part 3: Functions
— Part 5: Data communication protocol
— Part 6: Data communication conformance testing
Applications and project implementation are to form the subjects of future Parts 4 and 7.

© ISO 2014 – All rights reserved
iii

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ISO 16484-5:2014(E)
INTERNATIONAL STANDARD

Building automation and control systems (BACS) — Part 5: Data
communication protocol
1 Scope
This part of ISO 16484 defines data communication services and protocols for computer equipment
used for monitoring and control of heating, ventilation, air‐conditioning and refrigeration (HVAC&R)
and other building systems. It defines, in addition, an abstract, object‐oriented representation of
information communicated between such equipment, thereby facilitating the application and use of
digital control technology in buildings. The scope and field of application are furthermore detailed in
Clause 2 of the enclosed ANSI/ASHRAE publication.
2 Requirements
Requirements are the technical recommendations made in the following publication (reproduced on
the following pages), which is adopted as an International Standard:
ANSI/ASHRAE 135‐2012, A Data Communication Protocol for Building Automation and Control
Networks
The text on the back of the title page of the ANSI/ASHRAE standard and the policy statement on the last
page are not relevant for the purposes of international standardization.
The following International Standards are cited in the text:
ISO/IEC 7498 (all parts), Information technology — Open Systems Interconnection — Basic Reference
Model
ISO/TR 8509, Information processing systems — Open Systems Interconnection — Service conventions
ISO/IEC 8649, Information technology — Open Systems Interconnection — Service definition for the
Association Control Service Element
ISO/IEC 8802‐2, Information technology — Telecommunications and information exchange between
systems — Local and metropolitan area networks — Specific requirements — Part 2: Logical link control
ISO/IEC 8802‐3, Information technology — Telecommunications and information exchange between
systems — Local and metropolitan area networks — Specific requirements — Part 3: Carrier sense
multiple access with collision detection (CSMA/CD) access method and physical layer specifications
ISO/IEC 8822, Information technology — Open Systems Interconnection — Presentation service definition
ISO/IEC 8824 (all parts), Information technology — Abstract Syntax Notation One (ASN.1)
ISO/IEC 8825 (all parts), Information technology — ASN.1 encoding rules
ISO/IEC 8859‐1, Information technology — 8-bit single-byte coded graphic character sets — Part 1: Latin
alphabet No. 1
© ISO 2014 – All rights reserved
1

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ISO 16484-5:2014(E)
ISO/IEC 9545, Information technology — Open Systems Interconnection — Application Layer structure
ISO/IEC 10646, Information technology — Universal Multiple-Octet Coded Character Set (UCS)
3 Revision of ANSI/ASHRAE 135
It has been agreed with the American Society of Heating, Refrigerating and Air‐Conditioning Engineers
(ASHRAE) that Technical Committee ISO/TC 205 will be consulted in the event of any revision or
amendment of ANSI/ASHRAE 135. To this end, ANSI will act as a liaison body between ASHRAE and ISO.

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ANSI/ASHRAE Standard 135-2012
(Supersedes ANSI/ASHRAE Standard 135-2010)
A Data Communication
Protocol for
Building Automation
and Control Networks
See the History of Revisions at the end of this standard for approval dates by the ASHRAE Standards Committee, the ASHRAE
Board of Directors, and the American National Standards Institute.
This standard is under continuous maintenance by a Standing Standard Project Committee (SSPC) for which the Standards Com-
mittee has established a documented program for regular publication of addenda or revisions, including procedures for timely,
documented, consensus action on requests for change to any part of the standard. The change submittal form, instructions, and
deadlines may be obtained in electronic form from the ASHRAE website (www.ashrae.org) or in paper form from the Manager of
Standards. The latest edition of an ASHRAE Standard may be purchased from the ASHRAE website (www.ashrae.org) or from
ASHRAE Customer Service, 1791 Tullie Circle, NE, Atlanta, GA 30329-2305. E-mail: orders@ashrae.org. Fax: 404-321-5478.
Telephone: 404-636-8400 (worldwide), or toll free 1-800-527-4723 (for orders in US and Canada). For reprint permission, go to
www.ashrae.org/permissions.
© 2012 ASHRAE         ISSN 1041-2336

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ASHRAE Standing Standard Project Committee 135
CognizantTC:TC 1.4, ControlTheory and Applications
SPLS Liaisons: Richard Hall and Mark Modera
Carl Neilson Chair* David G. Holmberg* Frank Schubert
Bernhard Isler, Vice-Chair Daniel Kollodge* Gregory M. Spiro*
Michael Osborne, Secretary* Thomas Kurowski* David B. Thompson*
Donald P. Alexander Bryan Meyers Klaus Wagner
Chandrashekhar Appanna H. Michael Newman* Grant N. Wichenko*
Coleman L. Brumley* Dana Petersen Christoph Zeller
Clifford H. Copass* Suresh Ramachandran Scott Ziegenfus
Sharon E. Dinges David Robin Andrey Golovin
Stuart G. Donaldson* Takeji Toyoda, Jr.
Seán Giblin Klaus Bruno Wächter
*Denotes members of voting status when the document was approved for publication
The following persons served as consultants to the project committee:
Tomohino Asazuma Robert L. Johnson Duffy O’Craven
Dave Bohlmann Chris Jones Hideya Ochiai
Barry B. Bridges René Kälin Bob Old
Ernest C. Bryant Stephen Karg Farhad Omar
Steve Bushby Koji Kimura Dave Oravetz
Jim Butler Duane L. King Bill Pienta
Ryan Bykowski Bruno Kloubert René Quirighetti
A.J. Capowski Roland Laird David Ritter
Howard Coleman Brett Leida William Roberts
Hu Dou Rick Leinen Carl J. Ruther
David Fisher Simon Lemaire David G. Shike
Nils-Gunnar Fritz Joe Lenart Atsushi Shimadate
Rokuro Fuji J. Damian Ljungquist Brad Spencer
Fumio Fujimura John Lundstedt Ted Sunderland
Noriaki Fujiwara James G. Luth William O. Swan, III
Craig Gemmill John J. Lynch Hans Symanczik
Daniel P. Giorgis Kerry Lynn Bob Thomas
Rod Harruff Graham Martin Daniel A. Traill
John Hartman Jerry Martocci Stephen J. Treado
Teemu T. Heikkil Hirotaka Masui Bruce Westphal
Masahiro Ishiyama Konni Mergner J. Michael Whitcomb
Hiroshi Ito Charles Miltiades Cam Williams
Kosuke Ito Venkatesh Mohan Ove Wiuff
Sudhir Jaiswal Tsuyoshi Momose Ming Zhu
John Rohde Jensen Hans-Joachim Mundt Rob Zivney
Masaharu Nakamura

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ASHRAE STANDARDS COMMITTEE 2012–2013
Kenneth W. Cooper, Chair Julie M. Ferguson Janice C. Peterson
William F. Walter, Vice-Chair Krishnan Gowri Heather L. Platt
Douglass S. Abramson Cecily M. Grzywacz Ira G. Poston
Karim Amrane Richard L. Hall Douglas T. Reindl
Charles S. Barnaby Rita M. Harrold James R. Tauby
Hoy R. Bohanon, Jr. Adam W. Hinge James K. Vallort
Steven F. Bruning Debra H. Kennoy Craig P. Wray
David R. Conover Jay A. Kohler Charles H. Culp, III, BOD ExO
Steven J. Emmerich Rick A. Larson Constantinos A. Balaras, CO
Mark P. Modera
Stephanie C. Reiniche, Manager of Standards
SPECIAL NOTE
This American National Standard (ANS) is a national voluntary consensus standard developed under the auspices of ASHRAE.
Consensus is defined by the American National Standards Institute (ANSI), of which ASHRAE is a member and which has approved this
standard as an ANS, as“substantial agreement reached by directly and materially affected interest categories.This signifies the concurrence
of more than a simple majority, but not necessarily unanimity. Consensus requires that all views and objections be considered, and that an
effort be made toward their resolution.” Compliance with this standard is voluntary until and unless a legal jurisdiction makes compliance
mandatory through legislation.
ASHRAE obtains consensus through participation of its national and international members, associated societies, and public review.
ASHRAE Standards are prepared by a Project Committee appointed specifically for the purpose of writing the Standard. The Project
Committee Chair and Vice-Chair must be members of ASHRAE; while other committee members may or may not be ASHRAE members, all
must be technically qualified in the subject area of the Standard. Every effort is made to balance the concerned interests on all Project
Committees.
The Manager of Standards of ASHRAE should be contacted for:
a. interpretation of the contents of this Standard,
b. participation in the next review of the Standard,
c. offering constructive criticism for improving the Standard, or
d. permission to reprint portions of the Standard.
DISCLAIMER
ASHRAE uses its best efforts to promulgate Standards and Guidelines for the benefit of the public in light of available information and
acceptedindustrypractices.However,ASHRAEdoesnotguarantee,certify,orassurethesafetyorperformanceofanyproducts,components,
or systems tested, installed, or operated in accordance with ASHRAE’s Standards or Guidelines or that any tests conducted under its
Standards or Guidelines will be nonhazardous or free from risk.
ASHRAE INDUSTRIAL ADVERTISING POLICY ON STANDARDS
ASHRAE Standards and Guidelines are established to assist industry and the public by offering a uniform method of testing for rating
purposes,bysuggestingsafepracticesindesigningandinstallingequipment,byprovidingproperdefinitionsofthisequipment,andbyproviding
other information that may serve to guide the industry.The creation of ASHRAE Standards and Guidelines is determined by the need for them,
and conformance to them is completely voluntary.
In referring to this Standard or Guideline and in marking of equipment and in advertising, no claim shall be made, either stated or implied,
that the product has been approved by ASHRAE.

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Contents


CONTENTS
FOREWORD ………………………………………………………………………………………………………………….vii
1 PURPOSE . 1
2 SCOPE . 1
3 DEFINITIONS . 1
3.1 Terms Adopted from International Standards . 1
3.2 Terms Defined for this Standard . 2
3.3 Abbreviations and Acronyms Used in this Standard . 7
4 BACnet PROTOCOL ARCHITECTURE . 10
4.1 The BACnet Collapsed Architecture . 11
4.2 BACnet Network Topology . 13
4.3 Security . 15
5 THE APPLICATION LAYER . 16
5.1 The Application Layer Model . 16
5.2 Segmentation of BACnet Messages . 20
5.3 Transmission of BACnet APDUs . 21
5.4 Application Protocol State Machines . 25
5.5 Application Protocol Time Sequence Diagrams . 42
5.6 Application Layer Service Conventions . 51
6 THE NETWORK LAYER . 53
6.1 Network Layer Service Specification . 53
6.2 Network Layer PDU Structure . 55
6.3 Messages for Multiple Recipients . 60
6.4 Network Layer Protocol Messages . 61
6.5 Network Layer Procedures . 64
6.6 BACnet Routers . 66
6.7 Point-To-Point Half-Routers . 71
7 DATA LINK/PHYSICAL LAYERS: ISO 8802-3 ("Ethernet") LAN. 76
7.1 The Use of ISO 8802-2 Logical Link Control (LLC) . 76
7.2 Parameters Required by the LLC Primitives . 76
7.3 Parameters Required by the MAC Primitives . 76
7.4 Physical Media . 76
8 DATA LINK/PHYSICAL LAYERS: ARCNET LAN . 77
8.1 The Use of ISO 8802-2 Logical Link Control (LLC) . 77
8.2 Parameters Required by the LLC Primitives . 77
8.3 Mapping the LLC Services to the ARCNET MAC Layer . 77
8.4 Parameters Required by the MAC Primitives . 77
8.5 Physical Media . 77
9 DATA LINK/PHYSICAL LAYERS: MASTER-SLAVE/TOKEN PASSING (MS/TP) LAN . 79
9.1 Service Specification . 79
9.2 Physical Layer . 81
9.3 MS/TP Frame Format . 92
9.4 Overview of the MS/TP Network . 93
9.5 MS/TP Medium Access Control . 94
9.6 Cyclic Redundancy Check (CRC) . 111
9.7 Interfacing MS/TP LANs with Other BACnet LANs . 112
9.8 Responding BACnet User Processing of Messages from MS/TP . 112
9.9 Repeaters . 112
10 DATA LINK/PHYSICAL LAYERS: POINT-TO-POINT (PTP) . 114
10.1 Overview . 114
10.2 Service Specification . 114
10.3 Point-to-Point Frame Format. 119
10.4 PTP Medium Access Control Protocol . 121
11 DATA LINK/PHYSICAL LAYERS: EIA/CEA-709.1 ("LonTalk") LAN . 142
11.1 The Use of ISO 8802-2 Logical Link Control (LLC) . 142
11.2 Parameters Required by the LLC Primitives . 142
ANSI/ASHRAE Standard 135-2012  i

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Contents

11.3 Mapping the LLC Services to the LonTalk Application Layer . 142
11.4 Parameters Required by the Application Layer Primitives . 142
11.5 Physical Media . 143
12 MODELING CONTROL DEVICES AS A COLLECTION OF OBJECTS . 144
12.1 Accumulator Object Type . 148
12.2 Analog Input Object Type . 157
12.3 Analog Output Object Type . 162
12.4 Analog Value Object Type . 167
12.5 Averaging Object Type . 172
12.6 Binary Input Object Type . 175
12.7 Binary Output Object Type . 181
12.8 Binary Value Object Type . 187
12.9 Calendar Object Type . 193
12.10 Command Object Type . 195
12.11 Device Object Type . 199
12.12 Event Enrollment Object Type . 208
12.13 File Object Type . 215
12.14 Group Object Type . 218
12.15 Life Safety Point Object Type . 220
12.16 Life Safety Zone Object Type . 227
12.17 Loop Object Type. 234
12.18 Multi-state Input Object Type . 242
12.19 Multi-state Output Object Type . 247
12.20 Multi-state Value Object Type . 252
12.21 Notification Class Object Type . 257
12.22 Program Object Type . 260
12.23 Pulse Converter Object Type . 266
12.24 Schedule Object Type . 274
12.25 Trend Log Object Type . 280
12.26 Access Door Object Type. 289
12.27 Event Log Object Type . 297
...