IEC 61158-6-22:2010

IEC 61158-6-22 ®
Edition 1.0 2010-08
INTERNATIONAL
STANDARD
Industrial communication networks – Fieldbus specifications –
Part 6-22: Application layer protocol specification – Type 22 elements

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IEC 61158-6-22 ®
Edition 1.0 2010-08
INTERNATIONAL
STANDARD
Industrial communication networks – Fieldbus specifications –
Part 6-22: Application layer protocol specification – Type 22 elements

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
PRICE CODE
XC
ICS 25.04.40; 35.100.70; 35.110 ISBN 978-2-88912-136-6
– 2 – 61158-6-22 © IEC:2010(E)
CONTENTS
FOREWORD.6
INTRODUCTION.8
1 Scope.9
1.1 General .9
1.2 Specifications.10
1.3 Conformance.10
2 Normative references .10
3 Terms, definitions, abbreviations, symbols and conventions .11
3.1 Terms and definitions from other ISO/IEC standards .11
3.2 Fieldbus application-layer specific definitions .11
3.3 Abbreviations and symbols.15
3.4 Conventions .17
4 Application layer protocol specification .18
4.1 Operating principle .18
4.2 Device reference models .19
4.3 Application layer structure .21
5 FAL syntax description .21
5.1 Introduction and coding principles .21
5.2 Data type encoding .21
5.3 CeS encoding.25
5.4 ISO/IEC 8802-3 DLPDU communication inside Type 22 RTFL .72
5.5 Management encoding .72
6 FAL protocol state machines .73
6.1 Overview .73
6.2 Fieldbus service protocol machine (FSPM).74
6.3 Application relationship protocol machine (ARPM).74
6.4 DLL mapping protocol machine .74
7 AP-context state machine.75
8 FAL service protocol machine (FSPM).75
9 Application layer state machine (ALSM) .75
9.1 Description.75
9.2 States .77
9.3 Primitive definitions .78
9.4 State table.79
9.5 AL-service forwarding depending on AL-state.79
10 DLL mapping protocol machine (DMPM).80
10.1 Overview .80
10.2 Primitives exchanged between ALSM and DMPM .80
10.3 Primitives exchanged between DLL and DMPM .84
10.4 ALSM to DLL mapping.86
Bibliography.88

Figure 1 – RTFL device reference model .20
Figure 2 – RTFN device reference model.21
Figure 3 – Encoding of TimeOfDay value .22

61158-6-22 © IEC:2010(E) – 3 –
Figure 4 – Encoding of TimeDifference value.23
Figure 5 – Object dictionary addressing schema .26
Figure 6 – Relationships among protocol machines and adjacent layers .73
Figure 7 – ALSM protocol machine .74
Figure 8 – ALSM diagram .76

Table 1 – PDU element definition.18
Table 2 – Object definition .18
Table 3 – Transfer syntax for bit sequences.22
Table 4 – Transfer syntax for Integer data type.24
Table 5 – Transfer syntax for Unsigned data type .24
Table 6 – Object dictionary structure.25
Table 7 – Object dictionary object type definitions .26
Table 8 – Basic data type definitions.27
Table 9 – Complex data type definition .28
Table 10 – Communication section .29
Table 11 – Device type .31
Table 12 – Error register encoding.31
Table 13 – Error register.31
Table 14 – Object definition template.32
Table 15 – Encoding of event log entries .32
Table 16 – Event log.33
Table 17 – Manufacturer device name .33
Table 18 – Manufacturer HW version .34
Table 19 – Manufacturer SW version .34
Table 20 – CL configuration .34
Table 21 – Time sync IRQ configuration encoding .36
Table 22 – Time sync IRQ configuration .36
Table 23 – Time sync IRQ state.37
Table 24 – Store parameters read information .38
Table 25 – Store parameters.38
Table 26 – Restore parameters read information .39
Table 27 – Restore default parameters .39
Table 28 – Diagnostic information.41
Table 29 – Diagnostic threshold.44
Table 30 – IP address EMCY .45
Table 31 – Inhibit time EMCY.46
Table 32 – Encoding of consumer heartbeat entries.46
Table 33 – Consumer heartbeat list .47
Table 34 – Producer heartbeat parameter.47
Table 35 – Identity object.49
Table 36 – SDO protocol timeout .51
Table 37 – Enable client SDO parameter .51

– 4 – 61158-6-22 © IEC:2010(E)
Table 38 – Enable EMCY.52
Table 39 – PDO timeout tolerance .52
Table 40 – Store EDS .52
Table 41 – Storage format .53
Table 42 – OS command .53
Table 43 – OS command mode .54
Table 44 – OS debugger interface .55
Table 45 – OS prompt.56
Table 46 – Module list.57
Table 47 – Emergency subscriber encoding.57
Table 48 – Emergency subscriber.57
Table 49 – Client SDO parameter encoding .58
Table 50 – Client SDO parameter .58
Table 51 – Receive PDO communication parameter .59
Table 52 – Transmit PDO communication parameter .61
Table 53 – Mapping format .63
Table 54 – Receive PDO mapping parameter.63
Table 55 – Transmit PDO mapping parameter .64
Table 56 – Initiate SDO expedited download request .65
Table 57 – Initiate SDO expedited download response .65
Table 58 – Initiate SDO normal download request.65
Table 59 – Initiate SDO normal download response .66
Table 60 – SDO download request.66
Table 61 – SDO download response .66
Table 62 – Initiate SDO expedited upload request .67
Table 63 – Initiate SDO expedited upload response.67
Table 64 – Initiate SDO normal upload response .67
Table 65 – SDO upload request .68
Table 66 – SDO upload response .68
Table 67 – SDO abort request .68
Table 68 – SDO abort codes.68
Table 69 – Process data write request via MSC .69
Table 70 – Process data write request via CDC .70
Table 71 – Emergency request .70
Table 72 – Emergency error codes .70
Table 73 – Heartbeat request via MSC .71
Table 74 – Heartbeat request via CDC.71
Table 75 – Send frame request .72
Table 76 – Application layer management request .72
Table 77 – State transitions and management services.76
Table 78 – Primitives issued by ALSM to DLL .78
Table 79 – Primitives issued by DLL to ALSM .78
Table 80 – Primitives issued by FSPM to ALSM.78

61158-6-22 © IEC:2010(E) – 5 –
Table 81 – Primitives issued by ALSM to FSPM.78
Table 82 – ALSM state table .79
Table 83 – Application layer states and communication services.80
Table 84 – Primitives issued by ALSM to DMPM .80
Table 85 – Primitives issued by DMPM to ALSM .82
Table 86 – Primitives issued by DMPM to DLL .84
Table 87 – Primitives issued by DLL to DMPM .85
Table 88 – ALSM to DLL mapping.86

– 6 – 61158-6-22 © IEC:2010(E)
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
INDUSTRIAL COMMUNICATION NETWORKS –
FIELDBUS SPECIFICATIONS –
Part 6-22: Application layer protocol specification –
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
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2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
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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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4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
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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
members of its technical committees and IEC National Committees for any personal injury, property damage or
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
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 61158-6-22 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 61158-6-22 published in 2009. This first edition
constitutes a technical revision.

61158-6-22 © IEC:2010(E) – 7 –
The text of this standard is based on the following documents:
FDIS Report on voting
65C/607/FDIS 65C/621/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.

– 8 – 61158-6-22 © 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 protocol provides the application service by making use of the services
available from the data-link or other immediately lower layer. The primary aim of this standard
is to provide a set of rules for communication expressed in terms of the procedures to be
carried out by peer application entities (AEs) at the time of communication. These rules for
communication are intended to provide a sound basis for development in order to serve a
variety of purposes:
• as a guide for implementors and designers;
• for use in the testing and procurement of equipment;
• as part of an agreement for the admittance of systems into the open systems environment;
• as a refinement to the understanding of time-critical communications within OSI.
This standard is concerned, in particular, with the communication and interworking of sensors,
effectors and other automation devices. By using this standard together with other standards
positioned within the OSI or fieldbus reference models, otherwise incompatible systems may
work together in any combination.

61158-6-22 © IEC:2010(E) – 9 –
INDUSTRIAL COMMUNICATION NETWORKS –
FIELDBUS SPECIFICATIONS –
Part 6-22: Application layer protocol specification –
Type 22 elements
1 Scope
1.1 General
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 behavior provided by the
different Types of the fieldbus Application Layer in terms of:
a) the abstract syntax defining the application layer protocol data units conveyed between
communicating application entities;
b) the transfer syntax defining the application layer protocol data units conveyed between
communicating application entities;
c) the application context state machine defining the application service behavior visible
between communicating application entities; and
d) the application relationship state machines defining the communication behavior visible
between communicating application entities.
The purpose of this standard is to define the protocol provided to:
a) define the wire-representation of the service primitives defined in IEC 61158-5-22:2010;
and
b) define the externally visible behavior associated with their transfer.
This standard specifies the protocol of the IEC 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

– 10 – 61158-6-22 © IEC:2010(E)
applications are not specified; only a definition of what requests and responses they can
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 syntax and behavior of the application
layer protocol that conveys the application layer services defined in IEC 61158-5-22:2010.
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
protocols standardized in subparts of IEC 61158-6.
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 the application layer service definition standard.
Instead, conformance is achieved through implementation of this application layer protocol
specification.
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 61158-3-22:2010 , Industrial communication networks – Fieldbus specifications – Part 3-
22: Data-link layer service definition – Type 22 elements
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 5–
IEC 61158-5-22:2010
22: Application layer service definition - Type 22 elements
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
—————————
To be published.
61158-6-22 © IEC:2010(E) – 11 –
ISO/IEC 9545, Information Technology – Open Systems Interconnection – Application Layer
structure
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 Terms and definitions from other ISO/IEC standards
3.1.1 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
3.1.2 ISO/IEC 8822 terms
a) abstract syntax
b) presentation context
3.1.3 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
h) application-service-element
i) application control service element
3.1.4 ISO/IEC 8824-1 terms
a) object identifier
b) type
3.2 Fieldbus application-layer specific definitions
3.2.1
acyclic data
data which is transferred from time to time for dedicated purposes

– 12 – 61158-6-22 © IEC:2010(E)
3.2.2
bit
unit of information consisting of a 1 or a 0. This is the smallest data unit that can be
transmitted
3.2.3
cell
synonym for a single DL-segment which uses RTFL communication model
3.2.4
channel
path provided for conveying data
3.2.5
client
object which uses the services of a server by initiating a message to perform a task
3.2.6
communication cycle
fixed time period between which the root device issues empty frames for cyclic
communication initiation in which data is transmitted utilizing CDC and MSC
3.2.7
connection
logical binding between two application objects
3.2.8
cycle time
duration of a communication cycle
3.2.9
cyclic
events which repeat in a regular and repetitive manner
3.2.10
cyclic communication
periodic exchange of telegrams
3.2.11
cyclic data
data which is transferred in a regular and repetitive manner for dedicated purposes
3.2.12
cyclic data channel
CDC
part of one or more frames, which is reserved for cyclic data
3.2.13
data
generic term used to refer to any information carried over a fieldbus
3.2.14
device
physical entity connected to the fieldbus

61158-6-22 © IEC:2010(E) – 13 –
3.2.15
error
discrepancy between a computed, observed or measured value or condition and the specified
or theoretically correct value or condition
3.2.16
error code
identification number of a specific type of error
3.2.17
gateway
device acting as a linking element between different protocols
3.2.18
index
position of an object within the object dictionary
3.2.19
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
3.2.20
interface
shared boundary between two functional units, defined by functional characteristics, signal
characteristic, or other characteristics as appropriate
3.2.21
intra-cell communication
communication between a RTFL device and another RTFL device in the same cell
3.2.22
logical double line
sequence of root device and all ordinary devices processing the communication frame in
forward and backward direction
3.2.23
mapping parameters
set of values defining the correspondence between application objects and process data
objects
3.2.24
master clock
global time base for the PCS mechanism
3.2.25
message
ordered sequence of octets intended to convey data
3.2.26
message channel
MSC
part of one or more frames, which is reserved for acyclic data
3.2.27
network
set of devices connected by some type of communication medium, including any intervening
repeaters, bridges, routers and lower-layer gateways

– 14 – 61158-6-22 © IEC:2010(E)
3.2.28
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
3.2.29
precise clock synchronization
PCS
mechanism to synchronize clocks of RTFL devices and maintain a global time base
3.2.30
process data
data designated to be transferred cyclically or acyclically for the purpose of processing
3.2.31
process data object
dedicated data object(s) designated to be transferred cyclically or acyclically for the purpose
of processing
3.2.32
protocol
convention about the data formats, time sequences, and error correction in the data exchange
of communication systems
3.2.33
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
3.2.34
real time frame line
RTFL
communication model communicating in a logical double line
3.2.35
real time frame network
RTFN
communication model communicating in a switched network
3.2.36
round trip time
transmission time needed by a DLPDU from the RD to the last OD in forward and backward
direction
3.2.37
sub-index
sub-position of an individual element of an object within the object dictionary
3.2.38
timing signal
time-based indication of the occurrence of an event, commonly as an interrupt signal, used for
DL-user synchronization
61158-6-22 © IEC:2010(E) – 15 –
3.2.39
topology
physical network architecture with respect to the connection between the stations of the
communication system
3.3 Abbreviations and symbols
AE Application entity
AL Application layer
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
CDC Cyclic data channel
CL Communication layer
Cnf Confirmation
DA Device address or destination 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
FCS Frame check sequence
ID Identification
Ind Indication
IP Internet protocol
IPv4 IP version 4
– 16 – 61158-6-22 © IEC:2010(E)
IPv6 IP version 6
IRQ Interrupt request
LME Layer management entity
MAC Medium access control
MII Media independent interface
MSC-MTP Message channel message transfer protocol
MSC Message channel
OD Ordinary device
OS Operating system
OSI Open systems interconnection
PCS Precise clock synchronization
PDO Process data object
PID Packet ID
PTPMSU 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
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
61158-6-22 © IEC:2010(E) – 17 –
RxPDO Receive PDO
SA Source address
SDO Service data object
SEF Standard ISO/IEC 8802-3 Ethernet DLPDU
StdErr Standard error output
StdIn Standard input
StdOut Standard output
SYNC Synchronization
TCP Transmission control protocol
TT Transmission type
Tx Transmit direction
TxPDO Transmit PDO
UDP User datagram protocol
WO Write only
3.4 Conventions
3.4.1 General concept
The FAL is defined as a set of object-oriented ASEs. Each ASE is specified in a separate
clause. Each ASE specification is composed of three parts: its class definitions, its services,
and its protocol specification. The first two are contained in IEC 61158-5-22:2010. The
protocol specification for each of the ASEs is defined in this standard.
The class definitions define the attributes of the classes supported by each ASE. The
attributes are accessible from instances of the class using the Management ASE services
specified in IEC 61158-5-22:2010. The service specification defines the services that are
provided by the ASE.
This standard uses the descriptive conventions given in ISO/IEC 10731.
3.4.2 Abstract syntax conventions
The AL syntax elements related to PDU structure are described as shown in Table 1.
• Frame part denotes the element that will be replaced by this reproduction.
• Data field is the name of the elements.
• Data type denotes the type of the terminal symbol.
• Value/description contains the constant value or the meaning of the parameter.

– 18 – 61158-6-22 © IEC:2010(E)
Table 1 – PDU element definition
Frame part Data field Data type Value/description

The attributes of an object of the object dictionary are described in a form as shown in
Table 2.
• Index describes the position within the object dictionary of an object.
• Sub-index describes a single element of the object.
• Name denotes a name string for this attribute.
• Object type denotes the characterizing type for each object as specified in Table 7.
• Data type denotes the data type of this element.
• Category indicates whether the element is mandatory (M), optional (O) or depends upon
setting of other attributes (C).
• Access attribute shows the access right to this element. RO means read access right, RW
means read and write access right, while WO means write access right.
• PDO mapping denotes the possibility to map this attribute to TxPDO or RxPDO or to
indicate that this parameter is not mappable.
• Value range contains the value range of a dedicated element or ‘No’ for no pre-defined
value range.
• Value contains the constant value(s) and/or the meaning of the parameter or ‘No’ for no
pre-defined value.
Table 2 – Object definition
Attribute Value
Index
Sub-index
Name
Object type
Data type
Category
Access attribute
PDO mapping
Value range
Value
4 Application layer protocol specification
4.1 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 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 cell which uses RTFL for communication. An RTFL
cell consists of a root device (RD) and one or several ordinary devices (OD). The central

61158-6-22 © IEC:2010(E) – 19 –
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 req
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