IEC 61158-5-22:2010

IEC 61158-5-22 ®
Edition 1.0 2010-08
INTERNATIONAL
STANDARD
Industrial communication networks – Fieldbus specifications –
Part 5-22: Application layer service definition – Type 22 elements

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IEC 61158-5-22 ®
Edition 1.0 2010-08
INTERNATIONAL
STANDARD
Industrial communication networks – Fieldbus specifications –
Part 5-22: Application layer service definition – Type 22 elements

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
PRICE CODE
XC
ICS 25.04.40; 35.100.70; 35.110 ISBN 978-2-88912-115-1
– 2 – 61158-5-22 © IEC:2010(E)
CONTENTS
FOREWORD.4
INTRODUCTION.6
1 Scope.7
1.1 Overview .7
1.2 Specifications.8
1.3 Conformance.8
2 Normative references .8
3 Terms, definitions, abbreviations, symbols and conventions .9
3.1 ISO/IEC 7498-1 terms .9
3.2 ISO/IEC 8822 terms .9
3.3 ISO/IEC 9545 terms .9
3.4 ISO/IEC 8824-1 terms .10
3.5 Type 22 fieldbus application-layer specific definitions.10
3.6 Abbreviations and symbols.13
3.7 Conventions .16
4 Concepts .19
4.1 Common concepts.19
4.2 Type specific concepts .19
5 Data type ASE.23
5.1 Overview .23
5.2 Formal definition of data type objects .23
5.3 FAL defined data types.23
6 Communication model specification.31
6.1 Application service elements (ASEs) .31
6.2 Application relationships (ARs).74
Bibliography.79

Figure 1 – Producer-consumer interaction model .21
Figure 2 – RTFL device reference model .22
Figure 3 – RTFN device reference model.23
Figure 4 – Type 22 CeS device structure .32
Figure 5 – Successful SDO expedited download sequence .46
Figure 6 – Successful SDO normal download initialization sequence .46
Figure 7 – Successful SDO download sequence .46
Figure 8 – Successful SDO expedited upload sequence.47
Figure 9 – Successful SDO normal upload initialization sequence.47
Figure 10 – Successful SDO upload sequence.47
Figure 11 – Failed SDO expedited download initialization sequence .48
Figure 12 – Failed SDO download after initialization sequence .48
Figure 13 – Failed SDO download sequence.48
Figure 14 – Emergency sequence.49
Figure 15 – Heartbeat sequence .49
Figure 16 – Process data write sequence.50

61158-5-22 © IEC:2010(E) – 3 –
Figure 17 – PDO mapping principle .50
Figure 18 – Process data object.51
Figure 19 – SEF service sequence.64

Table 1 – Object dictionary structure.32
Table 2 – Initiate SDO expedited download service.54
Table 3 – Initiate SDO normal download service .55
Table 4 – SDO download service .56
Table 5 – Initiate SDO expedited upload service .57
Table 6 – Initiate SDO normal upload service .58
Table 7 – SDO upload service .60
Table 8 – SDO abort service.61
Table 9 – Process data write service.62
Table 10 – Emergency service (EMCY).62
Table 11 – Heartbeat service .63
Table 12 – Send frame service .65
Table 13 – AL-Network verification service .67
Table 14 – AL-RTFL configuration service .68
Table 15 – AL-DelayMeasurement start service .69
Table 16 – AL-DelayMeasurement read service .70
Table 17 – PCS configuration service .70
Table 18 – MII read service .71
Table 19 – MII write service .71
Table 20 – AL-RTFN scan network read service .72
Table 21 – Application layer management service.72
Table 22 – Start synchronization service.73
Table 23 – Stop synchronization service .73
Table 24 – PTPNSU AREP class .75
Table 25 – PTMNSU AREP class.76
Table 26 – PTPNSC AREP class .76
Table 27 – PTPUTC AREP class.76
Table 28 – FAL services by AREP class .77
Table 29 – FAL services by AREP role .78

– 4 – 61158-5-22 © IEC:2010(E)
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
INDUSTRIAL COMMUNICATION NETWORKS –
FIELDBUS SPECIFICATIONS –
Part 5-22: Application layer service definition –
Type 22 elements
FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, IEC publishes International Standards, Technical Specifications,
Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC
Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested
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with the International Organization for Standardization (ISO) in accordance with conditions determined by
agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
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3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
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between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
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5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
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6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
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Publications.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
NOTE 1 Use of some of the associated protocol Types is restricted by their intellectual-property-right holders. In
all cases, the commitment to limited release of intellectual-property-rights made by the holders of those rights
permits a particular data-link layer protocol Type to be used with physical layer and application layer protocols in
Type combinations as specified explicitly in the profile parts. Use of the various protocol Types in other
combinations may require permission of their respective intellectual-property-right holders.
International Standard IEC 61158-5-22 has been prepared by subcommittee 65C: Industrial
networks, of IEC technical committee 65: Industrial-process measurement, control and
automation.
This standard cancels and replaces IEC/PAS 61158-5-22 published in 2009. This first edition
constitutes a technical revision.

61158-5-22 © IEC:2010(E) – 5 –
The text of this standard is based on the following documents:
FDIS Report on voting
65C/606/FDIS 65C/620/RVD
Full information on the voting for the approval of this International Standard can be found in
the report on voting indicated in the above table.
This publication has been drafted in accordance with ISO/IEC Directives, Part 2.
A list of all parts of the IEC 61158 series, published under the general title Industrial
communication networks – Fieldbus specifications, can be found on the IEC web site.
The committee has decided that the contents of this publication will remain unchanged until
the stability date indicated on the IEC web site under "http://webstore.iec.ch" in the data
related to the specific publication. At this date, the publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
NOTE 2 The revision of this standard will be synchronized with the other parts of the IEC 61158 series.

– 6 – 61158-5-22 © IEC:2010(E)
INTRODUCTION
This part of IEC 61158 is one of a series produced to facilitate the interconnection of
automation system components. It is related to other standards in the set as defined by the
“three-layer” fieldbus reference model described in IEC/TR 61158-1.
The application service is provided by the application protocol making use of the services
available from the data-link or other immediately lower layer. This standard defines the
application service characteristics that fieldbus applications and/or system management may
exploit.
Throughout the set of fieldbus standards, the term “service” refers to the abstract capability
provided by one layer of the OSI Basic Reference Model to the layer immediately above.
Thus, the application layer service defined in this standard is a conceptual architectural
service, independent of administrative and implementation divisions.

61158-5-22 © IEC:2010(E) – 7 –
INDUSTRIAL COMMUNICATION NETWORKS –
FIELDBUS SPECIFICATIONS –
Part 5-22: Application layer service definition –
Type 22 elements
1 Scope
1.1 Overview
The fieldbus application layer (FAL) provides user programs with a means to access the
fieldbus communication environment. In this respect, the FAL can be viewed as a “window
between corresponding application programs.”
This standard provides common elements for basic time-critical and non-time-critical
messaging communications between application programs in an automation environment and
material specific to Type 22 fieldbus. The term “time-critical” is used to represent the
presence of a time-window, within which one or more specified actions are required to be
completed with some defined level of certainty. Failure to complete specified actions within
the time window risks failure of the applications requesting the actions, with attendant risk to
equipment, plant and possibly human life.
This standard defines in an abstract way the externally visible service provided by the fieldbus
application layer in terms of
a) an abstract model for defining application resources (objects) capable of being
manipulated by users via the use of the FAL service;
b) the primitive actions and events of the service;
c) the parameters associated with each primitive action and event, and the form which they
take; and
d) the interrelationship between these actions and events, and their valid sequences.
The purpose of this standard is to define the services provided to
a) the FAL user at the boundary between the user and the application layer of the fieldbus
reference model; and
b) Systems Management at the boundary between the application layer and Systems
Management of the fieldbus reference model.
This standard specifies the structure and services of the fieldbus application layer, in
conformance with the OSI Basic Reference Model (ISO/IEC 7498) and the OSI application
layer structure (ISO/IEC 9545).
FAL services and protocols are provided by FAL application-entities (AE) contained within the
application processes. The FAL AE is composed of a set of object-oriented application service
elements (ASEs) and a layer management entity (LME) that manages the AE. The ASEs
provide communication services that operate on a set of related application process object
(APO) classes. One of the FAL ASEs is a management ASE that provides a common set of
services for the management of the instances of FAL classes.
Although these services specify, from the perspective of applications, how request and
responses are issued and delivered, they do not include a specification of what the requesting
and responding applications are to do with them. That is, the behavioral aspects of the
applications are not specified; only a definition of what requests and responses they can

– 8 – 61158-5-22 © IEC:2010(E)
send/receive is specified. This permits greater flexibility to the FAL users in standardizing
such object behavior. In addition to these services, some supporting services are also defined
in this standard to provide access to the FAL to control certain aspects of its operation.
1.2 Specifications
The principal objective of this standard is to specify the characteristics of conceptual
application layer services suitable for time-critical communications, and thus supplement the
OSI Basic Reference Model in guiding the development of application layer protocols for time-
critical communications.
A secondary objective is to provide migration paths from previously-existing industrial
communications protocols. It is this latter objective which gives rise to the diversity of services
standardized as the various Types of IEC 61158, and the corresponding protocols
standardized in subparts of IEC 61158-6.
This specification may be used as the basis for formal application programming interfaces.
Nevertheless, it is not a formal programming interface, and any such interface will need to
address implementation issues not covered by this specification, including:
a) the sizes and octet ordering of various multi-octet service parameters; and
b) the correlation of paired request and confirm, or indication and response, primitives.
1.3 Conformance
This standard does not specify individual implementations or products, nor does it constrain
the implementations of application layer entities within industrial automation systems.
There is no conformance of equipment to this application layer service definition standard.
Instead, conformance is achieved through implementation of conforming application layer
protocols that fulfill the application layer services as defined in this standard.
2 Normative references
The following referenced documents are indispensable for the application of this document.
For dated references, only the edition cited applies. For undated references, the latest edition
of the referenced document (including any amendments) applies.
IEC 60559, Binary floating-point arithmetic for microprocessor systems
IEC 61131-3, Programmable controllers – Part 3: Programming languages
IEC/TR 61158-1:2010 , Industrial communication networks – Fieldbus specifications – Part 1:
Overview and guidance for the IEC 61158 and IEC 61784 series
IEC 61158-4-22:2010 , Industrial communication networks – Fieldbus specifications –
Part 4-22: Data-link layer protocol specification – Type 22 elements
, Industrial communication networks – Fieldbus specifications – Part 6-
IEC 61158-6-22:2010
22: Application layer protocol specification – Type 22 elements
ISO/IEC 646, Information technology – ISO 7-bit coded character set for information
interchange
—————————
To be published.
61158-5-22 © IEC:2010(E) – 9 –
ISO/IEC 7498-1, Information technology – Open Systems Interconnection – Basic Reference
Model: The Basic Model
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 8824-1, Information Technology – Abstract Syntax Notation One (ASN.1):
Specification of basic notation
ISO/IEC 9545, Information Technology – Open Systems Interconnection – Application Layer
structure
ISO/IEC 10646, Information technology – Universal Multiple-Octet Coded Character Set
(UCS)
ISO/IEC 10731, Information technology – Open Systems Interconnection – Basic Reference
Model – Conventions for the definition of OSI services
3 Terms, definitions, abbreviations, symbols and conventions
For the purposes of this document, the following terms as defined in these publications apply:
3.1 ISO/IEC 7498-1 terms
a) application entity
b) application process
c) application protocol data unit
d) application service element
e) application entity invocation
f) application process invocation
g) application transaction
h) real open system
i) transfer syntax
3.2 ISO/IEC 8822 terms
a) abstract syntax
b) presentation context
3.3 ISO/IEC 9545 terms
a) application-association
b) application-context
c) application context name
d) application-entity-invocation
e) application-entity-type
f) application-process-invocation
g) application-process-type
– 10 – 61158-5-22 © IEC:2010(E)
h) application-service-element
i) application control service element
3.4 ISO/IEC 8824-1 terms
a) object identifier
b) type
3.5 Type 22 fieldbus application-layer specific definitions
3.5.1
application
function for which data is exchanged
3.5.2
application object
representation of a particular component within a device
3.5.3
acyclic data
data which is transferred from time to time for dedicated purposes
3.5.4
bit
unit of information consisting of a 1 or a 0. This is the smallest data unit that can be
transmitted
3.5.5
cell
synonym for a single DL-segment which uses RTFL communication model
3.5.6
channel
path provided for conveying data
3.5.7
client
object which uses the services of a server by initiating a message to perform a task
3.5.8
communication cycle
fixed time period between which the root device issues empty DLPDUs for cyclic
communication initiation in which data is transmitted utilizing CDC and MSC
3.5.9
connection
logical binding between two application objects
3.5.10
cycle time
duration of a communication cycle
3.5.11
cyclic
events which repeat in a regular and repetitive manner

61158-5-22 © IEC:2010(E) – 11 –
3.5.12
cyclic communication
periodic exchange of telegrams
3.5.13
cyclic data
data which is transferred in a regular and repetitive manner for dedicated purposes
3.5.14
cyclic data channel
CDC
part of one or more DLPDUs, which is reserved for cyclic data
3.5.15
data
generic term used to refer to any information carried over a fieldbus
3.5.16
device
physical entity connected to the fieldbus
3.5.17
error
discrepancy between a computed, observed or measured value or condition and the specified
or theoretically correct value or condition
3.5.18
error code
identification number of a specific type of error
3.5.19
gateway
device acting as a linking element between different protocols
3.5.20
index
position of an object within the object dictionary
3.5.21
inter-cell communication
communication between a RTFL device and a RTFN device or communication between a
RTFL device and another RTFL device in different cells linked by RTFN
3.5.22
interface
shared boundary between two functional units, defined by functional characteristics, signal
characteristic, or other characteristics as appropriate
3.5.23
intra-cell communication
communication between a RTFL device and another RTFL device in the same cell
3.5.24
logical double line
sequence of root device and all ordinary devices processing the communication DLPDU in
forward and backward direction

– 12 – 61158-5-22 © IEC:2010(E)
3.5.25
mapping parameters
set of values defining the correspondence between application objects and process data
objects
3.5.26
master clock
global time base for the PCS mechanism
3.5.27
message
ordered sequence of octets intended to convey data
3.5.28
message channel
MSC
part of one or more DLPDUs, which is reserved for acyclic data
3.5.29
network
set of devices connected by some type of communication medium, including any intervening
repeaters, bridges, routers and lower-layer gateways
3.5.30
ordinary device
OD
slave in the communication system, which utilizes RTFL for cyclic and acyclic data
interchange with other ODs in the same logical double line
3.5.31
precise clock synchronization
PCS
mechanism to synchronize clocks of RTFL devices and maintain a global time base
3.5.32
process data
data designated to be transferred cyclically or acyclically for the purpose of processing
3.5.33
process data object
dedicated data object(s) designated to be transferred cyclically or acyclically for the purpose
of processing
3.5.34
protocol
convention about the data formats, time sequences, and error correction in the data exchange
of communication systems
3.5.35
root device
RD
master in the communication system, which organises, initiates and controls the RTFL cyclic
and acyclic data interchange for one logical double line
3.5.36
real time frame line
RTFL
communication model communicating in a logical double line

61158-5-22 © IEC:2010(E) – 13 –
3.5.37
real time frame network
RTFN
communication model communicating in a switched network
3.5.38
round trip time
transmission time needed by a DLPDU from the RD to the last OD in forward and backward
direction
3.5.39
sub-index
sub-position of an individual element of an object within the object dictionary
3.5.40
timing signal
time-based indication of the occurrence of an event, commonly as an interrupt signal, used for
DL-user synchronization
3.5.41
topology
physical network architecture with respect to the connection between the stations of the
communication system
3.6 Abbreviations and symbols
AE Application entity
AL Application layer
ALME Application layer management entity
AP Application process
APDU Application layer protocol data unit
APO Application process object
AR Application relationship
AREP Application relationship end point
ASE Application service element
CAN Controller area network
CDC Cyclic data channel
CDCL CDC line
CDCN CDC network
CeS CANopen expands Type 22
CL Communication layer
– 14 – 61158-5-22 © IEC:2010(E)
Cnf Confirmation
DA Device address
DHCP Dynamic Host Configuration Protocol
DL- Data-link layer (as a prefix)
DLL DL-layer
DLPDU DL-protocol data unit
EDS Electronic data sheet
EMCY Emergency
FAL Fieldbus application layer
GW Gateway
ID Identification
IETF Internet Engineering Task Force
Ind Indication
IP Internet protocol
IPv4 IP version 4
IPv6 IP version 6
IRQ Interrupt request
LME Layer management entity
MAC Medium access control
MC Master clock
MII Media independent interface
MSC Message channel
MSCL MSC line
MSCN MSC network
OD Ordinary device
OS Operating system
61158-5-22 © IEC:2010(E) – 15 –
OSI Open systems interconnection
PCS Precise clock synchronization
PDO Process data object
PHY Physical interface controller
PID Packet ID
PTMNSU Point-to-multipoint network-scheduled unconfirmed
PTPNSC Point-to-point network-scheduled confirmed
PTPNSU Point-to-point network-scheduled unconfirmed
PTPUTC Point-to-point user-triggered confirmed
RD Root device
Req Request
RFC Request for comments
Rsp Response
RTF Real time frame
RTFL Real time frame line
RTFN Real time frame network
RO Read only
RW Read and write access
Rx Receive direction
RxPDO Receive PDO
SDO Service data object
SEF Standard ISO/IEC 8802-3 DLPDU
StdErr Standard error output
StdIn Standard input
StdOut Standard output
SYNC Synchronization
– 16 – 61158-5-22 © IEC:2010(E)
TCP Transmission control protocol
TT Transmission type
Tx Transmit direction
TxPDO Transmit PDO
UDP User datagram protocol
WO Write only
3.7 Conventions
3.7.1 Overview
The FAL is defined as a set of object-oriented ASEs. Each ASE is specified in a separate sub-
clause. Each ASE specification is composed of two parts, its class specification, and its
service specification.
The class specification defines the attributes of the class. The attributes are accessible from
instances of the class using the Object Management ASE services specified in Clause 5 of
this standard. The service specification defines the services that are provided by the ASE.
3.7.2 General conventions
This standard uses the descriptive conventions given in ISO/IEC 10731.
3.7.3 Conventions for class definitions
Class definitions are described using templates. Each template consists of a list of attributes
for the class. The general form of the template is shown below:
FAL ASE: ASE Name
CLASS: Class name
CLASS ID: #
PARENT CLASS: Parent class name
ATTRIBUTES:
1 (o) Key Attribute: numeric identifier
2 (o) Key Attribute: name
3 (m) Attribute: attribute name(values)
4 (m) Attribute: attribute name(values)
4.1 (s) Attribute: attribute name(values)
4.2 (s) Attribute: attribute name(values)
4.3 (s) Attribute: attribute name(values)
5. (c) Constraint: constraint expression
5.1 (m) Attribute: attribute name(values)
5.2 (o) Attribute: attribute name(values)
6 (m) Attribute: attribute name(values)
6.1 (s) Attribute: attribute name(values)
6.2 (s) Attribute: attribute name(values)
SERVICES:
61158-5-22 © IEC:2010(E) – 17 –
1 (o) OpsService: service name
2 (c) Constraint: constraint expression
2.1 (o) OpsService: service name
3 (m) MgtService: service name

(1) The "FAL ASE:" entry is the name of the FAL ASE that provides the services for the
class being specified.
(2) The "CLASS:" entry is the name of the class being specified. All objects defined using
this template will be an instance of this class. The class may be specified by this
standard, or by a user of this standard.
(3) The "CLASS ID:" entry is a number that identifies the class being specified. This
number is unique within the FAL ASE that will provide the services for this class. When
qualified by the identity of its FAL ASE, it unambiguously identifies the class within the
scope of the FAL. The value "NULL" indicates that the class cannot be instantiated.
Class IDs between 1 and 255 are reserved by this standard to identify standardized
classes. They have been assigned to maintain compatibility with existing national
standards. CLASS IDs between 256 and 2048 are allocated for identifying user defined
classes.
(4) The "PARENT CLASS:" entry is the name of the parent class for the class being
specified. All attributes defined for the parent class and inherited by it are inherited for
the class being defined, and therefore do not have to be redefined in the template for
this class.
NOTE The parent-class "TOP" indicates that the class being defined is an initial class definition. The parent
class TOP is used as a starting point from which all other classes are defined. The use of TOP is reserved for
classes defined by this standard.
(5) The "ATTRIBUTES" label indicate that the following entries are attributes defined for
the class.
a) Each of the attribute entries contains a line number in column 1, a mandatory (m) /
optional (o) / conditional (c) / selector (s) indicator in column 2, an attribute type
label in column 3, a name or a conditional expression in column 4, and optionally a
list of enumerated values in column 5. In the column following the list of values, the
default value for the attribute may be specified.
b) Objects are normally identified by a numeric identifier or by an object name, or by
both. In the class templates, these key attributes are defined under the key
attribute.
c) The line number defines the sequence and the level of nesting of the line. Each
nesting level is identified by period. Nesting is used to specify
i) fields of a structured attribute (4.1, 4.2, 4.3),
ii) attributes conditional on a constraint statement (5). Attributes may be
mandatory (5.1) or optional (5.2) if the constraint is true. Not all optional
attributes require constraint statements as does the attribute defined in (5.2).
iii) the selection fields of a choice type attribute (6.1 and 6.2).
(6) The "SERVICES" label indicates that the following entries are services defined for the
class.
a) An (m) in column 2 indicates that the service is mandatory for the class, while an
(o) indicates that it is optional. A (c) in this column indicates that the service is
conditional. When all services defined for a class are defined as optional, at least

– 18 – 61158-5-22 © IEC:2010(E)
one has to be selected when an instance of the class is defined.
b) The label "OpsService" designates an operational service (1).
c) The label "MgtService" designates an management service (2).
d) The line number defines the sequence and the level of nesting of the line. Each
nesting level is identified by period. Nesting within the list of services is used to
specify services conditional on a constraint statement.
3.7.4 Conventions for service definitions
3.7.4.1 Overview
The service model, service primitives, and time-sequence diagrams used are entirely abstract
descriptions; they do not represent a specification for implementation.
3.7.4.2 Service parameters
Service primitives are used to represent service user/service provider interactions
(ISO/IEC 10731). They convey parameters which indicate information available in the
user/provider interaction. In any particular interface, not all parameters need be explicitly
stated.
The service specifications of this standard use a tabular format to describe the component
parameters of the ASE service primitives. The parameters which apply to each group of
service primitives are set out in tables. Each table consists of up to five columns for the:
1) parameter name;
2) request primitive;
3) indication primitive;
4) response primitive; and
5) confirm primitive.
One parameter (or component of it) is listed in each row of each table. Under the appropriate
service primitive columns, a code is used to specify the type of usage of the parameter on the
primitive specified in the column:
M parameter is mandatory for the primitive.
U parameter is a User option, and may or may not be provided depending on
dynamic usage of the service user. When not provided, a default value for
the parameter is assumed.
C parameter is conditional upon other parameters or upon the environment of
the service user.
(blank) parameter is never present.
S parameter is a selected item.
Some entries are further qualified by items in brackets. These may be
c) a parameter-specific constraint:
“(=)” indicates that the parameter is semantically equivalent to the parameter in the
service primitive to its immediate left in the table.
d) an indication that some note applies to the entry:

61158-5-22 © IEC:2010(E) – 19 –
“(n)” indicates that the following note "n" contains additional information pertaining to the
parameter and its use.
3.7.4.3 Service procedures
The procedures are defined in terms of:
• the interactions between application entities through the exchange of fieldbus Application
Protocol Data Units; and
• the interactions between an application layer service provider and an application layer
service user in the same system through the invocation of application layer service
primitives.
These procedures are applicable to instances of communication between systems which
support time-constrained communications services within the fieldbus application layer.
4 Concepts
4.1 Common concepts
All of IEC/TR 61158-1:2010, Clause 9 is incorporated by reference, except as specifically
overridden in 4. 2.
4.2 Type specific concepts
4.2.1 Operating principle
Type 22 consists of two types of communication models: RTFL and RTFN. RTFL is used to
ensure synchronized cyclic real-time communication. RTFN is used in to network several
RTFL cells to an overall system providing data interchange between several RTFL cells and
between RTFL cells and RTFN devices.
In this context, a RTFL cell describes a DL-segment which uses RTFL for communication. An
RTFL cell consists of a root device (RD) and one or several ordinary devices (OD). The
central RTFL cell element is the root device which organizes and controls RTFL cell
sequences such as cyclic real-time frame sending. A RTFL RD has at least one connection to
RTFL, and can include a gateway (GW) which additionally has connection to RTFN. As each
OD in the RTFL cell can only have a RTFL connection, the RD incorporating a GW therefore
operates as a link between RTFL and RTFN. RTFN communication is not coordinated like
communication in RTFL, but utilized by a switched fully duplex ISO/IEC 8802-3 network.
Thus, no determinism can be guaranteed for RTFN data transfer.
Communication of process and service data is accommodated by Type 22 networks using
different mechanisms (channels) in RTFL and RTFN. Cyclic data can be transferred over the
cyclic data channel (CDC). The message channel (MSC) allows additional acyclic data
communication and is used for service data exchange.
Service data is typically transferred acyclic and is used for transfer of parameters, control
commands, status and diagnostic data as well as for generally larger data segments. Service
data are transferred either event driven or user driven (acyclic character). Parameter data
used in particular in device configuration do not require strict time conditions whereas
diagnostic data may have much greater time requirements.
In contrast, process data is typically transferred cyclically with different cycle times and higher
real-time requirements.
Type 22 AL supports a variety of services and protocols to meet these differing requirements.
Both communication models support the same fieldbus application layer. The services and
protocols are mapped to the corresponding DL-services.

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4.2.2 Communication model overview
4.2.2.1 Overview
Type 22 technology essentially specifies two communication models with corresponding
protocols. RTFL communication is intended for fast machine communication while RTFN
provides for the networking of individual machines or cells. The corresponding protocols aim
to offer an equal set of services for cyclic process data exchange as well as for acyclic
message data communication.
The application relationship can be modeled independent of communication relationship.
4.2.2.2 Communication model RTFL
For RTFL communication model, communication follows a line topology. RTFL communication
is based on cyclic data transfer in an ISO/IEC 8802-3 DLPDU. This basic cyclic data transfer
is provided by a special device, the root device (RD). Root devices act as communication
master to cyclically initiate communication. The DLPDUs originated by the root device are
passed to the Type 22 ordinary devices (OD). Each ordinary device receives the DLPDU,
writes its data and passes the DLPDU on. A RTFL network requires exactly one root device.
The last ordinary device of a RTFL network sends the processed DLPDU
...