IEC PAS 61158-6-22:2009

IEC/PAS 61158-6-22 ®
Edition 1.0 2009-08
PUBLICLY AVAILABLE
SPECIFICATION
PRE-STANDARD
Industrial communication networks – Fieldbus specifications –
Part 6-22: Application layer protocol specification – Type SNpTYPE elements

IEC/PAS 61158-6-22:2009(E)
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IEC/PAS 61158-6-22 ®
Edition 1.0 2009-08
PUBLICLY AVAILABLE
SPECIFICATION
PRE-STANDARD
Industrial communication networks – Fieldbus specifications –
Part 6-22: Application layer protocol specification – Type SNpTYPE elements

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
PRICE CODE
XD
ICS 25.040.40; 35.100.70 ISBN 978-2-88910-797-1
– 2 – PAS 61158-6-22 © IEC:2009(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 Referenced terms and definitions .11
3.1.1 ISO/IEC 7498-1 terms .11
3.1.2 ISO/IEC 8822 terms.11
3.1.3 ISO/IEC 9545 terms.11
3.1.4 ISO/IEC 8824 terms.11
3.2 Fieldbus application-layer specific definitions .11
3.3 Abbreviations and symbols.14
3.4 Conventions .17
3.4.1 General concept .17
3.4.2 Abstract syntax conventions .17
4 Application layer protocol specification .18
4.1 Operating principle .18
4.2 Device reference models .19
4.2.1 RTFL device reference model.19
4.2.2 RTFN device reference model .19
4.3 Application Layer structure .20
5 FAL syntax description .20
5.1 Introduction and coding principles .20
5.2 Data type encoding .20
5.2.1 Overview .20
5.2.2 Transfer syntax for bit sequences .21
5.2.3 Encoding of a Boolean value .21
5.2.4 TimeOfDay .21
5.2.5 TimeDifference .22

5.2.6 Encoding of floating point values .22
5.2.7 Encoding of Integer values .22
5.2.8 Encoding of Unsigned Integer values.23
5.2.9 Encoding of an OctetString value.24
5.2.10 Encoding of a VisibleString value .24
5.2.11 Encoding of an UnicodeString value .24
5.3 CeS encoding.24
5.3.1 Object dictionary .24
5.3.2 SDO .67
5.3.3 Process data write.72
5.3.4 Emergency .72
5.3.5 Heartbeat .74
5.4 Standard Ethernet frame communication .74
5.4.1 Overview .74

PAS 61158-6-22 © IEC:2009(E) – 3 –

5.4.2 Send frame request .74

5.5 Management encoding .75

5.5.1 DLL management services .75

5.5.2 Application layer management.75

6 FAL protocol state machines .75

6.1 Overview .75

6.2 Fieldbus service protocol machine (FSPM).77

6.3 Application relationship protocol machine (ARPM).77

6.4 DLL mapping protocol machine .77

7 AP-context state machine.77
8 FAL service protocol machine (FSPM).77
9 Application layer state machine (ALSM) .78
9.1 Description.78
9.2 States .80
9.2.1 Initialization (INIT) .80
9.2.2 ResetApplication (ResAP) .80
9.2.3 ResetCommunication (ResCO) .80
9.2.4 PreOperational (PreOP) .80
9.2.5 Operational (OP) .81
9.2.6 Stopped (ST) .81
9.3 Primitive definitions .81
9.3.1 FAL primitives .81
9.3.2 Primitives exchanged between DLL and ALSM .81
9.3.3 Primitives exchanged between FSPM and ALSM .81
9.4 State table.83
9.5 AL-service forwarding depending on AL-state.84
10 DLL mapping protocol machine (DMPM).84
10.1 Overview .84
10.2 Primitives exchanged between ALSM and DMPM .84
10.3 Primitives exchanged between DLL and DMPM .89
10.4 ALSM to DLL mapping.91

Figure 1 – RTFL device reference model .19
Figure 2 – RTFN device reference model.20

Figure 3 – Encoding of TimeOfDay value .21
Figure 4 – Encoding of TimeDifference value.22
Figure 5 – Object dictionary addressing schema .25
Figure 6 – Relationships among protocol machines and adjacent layers .76
Figure 7 – ALSM protocol machine .77
Figure 8 – ALSM diagram .79

Table 1 – PDU element definition.17
Table 2 – Object definition .18
Table 3 – Transfer syntax for bit sequences.21
Table 4 – Transfer syntax for Integer data type.23
Table 5 – Transfer syntax for Unsigned data type .23

– 4 – PAS 61158-6-22 © IEC:2009(E)

Table 6 – Object dictionary structure.24

Table 7 – Object dictionary object type definitions .25

Table 8 – Basic data type definitions.26

Table 9 – Complex data type definition .27

Table 10 – Communication section .28

Table 11 – Device type .30

Table 12 – Error register encoding.30

Table 13 – Error register.30

Table 14 – Object definition template.31
Table 15 – Encoding of event log entries .31
Table 16 – Event log.32
Table 17 – Manufacturer device name .32
Table 18 – Manufacturer HW version .33
Table 19 – Manufacturer SW version .33
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 .37
Table 25 – Store parameters.38
Table 26 – Restore parameters read information .39
Table 27 – Restore default parameters .39
Table 28 – Diagnostic information.40
Table 29 – Diagnostic threshold.43
Table 30 – IP address EMCY .45
Table 31 – Inhibit time EMCY.45
Table 32 – Encoding of consumer heartbeat entries.46
Table 33 – Consumer heartbeat list .47
Table 34 – Producer heartbeat parameter.48
Table 35 – Identity object.50
Table 36 – SDO protocol timeout .51

Table 37 – Enable client SDO parameter .52
Table 38 – Enable EMCY.52
Table 39 – PDO timeout tolerance .52
Table 40 – Store EDS .53
Table 41 – Storage format .53
Table 42 – OS command .54
Table 43 – OS command mode .55
Table 44 – OS debugger interface .56
Table 45 – OS prompt.57
Table 46 – Module list.58
Table 47 – Emergency subscriber encoding.58
Table 48 – Emergency subscriber.59

PAS 61158-6-22 © IEC:2009(E) – 5 –

Table 49 – Client SDO parameter encoding .59

Table 50 – Client SDO parameter .60

Table 51 – Receive PDO communication parameter .61

Table 52 – Transmit PDO communication parameter .63

Table 53 – Mapping format .65

Table 54 – Receive PDO mapping parameter.65

Table 55 – Transmit PDO mapping parameter .66

Table 56 – Initiate SDO expedited download request .67

Table 57 – Initiate SDO expedited download response .67
Table 58 – Initiate SDO normal download request.67
Table 59 – Initiate SDO normal download response .68
Table 60 – SDO download request.68
Table 61 – SDO download response .68
Table 62 – Initiate SDO expedited upload request .69
Table 63 – Initiate SDO expedited upload response.69
Table 64 – Initiate SDO normal upload response .69
Table 65 – SDO upload request .70
Table 66 – SDO upload response .70
Table 67 – SDO abort request .70
Table 68 – SDO abort codes.71
Table 69 – Process data write request via MSC .72
Table 70 – Process data write request via CDC .72
Table 71 – Emergency request .72
Table 72 – Emergency error codes .73
Table 73 – Heartbeat request via MSC .74
Table 74 – Heartbeat request via CDC.74
Table 75 – Send frame request .74
Table 76 – Application layer management request .75
Table 77 – State transitions and management services.80
Table 78 – Primitives issued by ALSM to DLL .81
Table 79 – Primitives issued by DLL to ALSM .81

Table 80 – Primitives issued by FSPM to ALSM.81
Table 81 – Primitives issued by ALSM to FSPM.82
Table 82 – ALSM state table .83
Table 83 – Application layer states and communication services.84
Table 84 – Primitives issued by ALSM to DMPM .84
Table 85 – Primitives issued by DMPM to ALSM .87
Table 86 – Primitives issued by DMPM to DLL .89
Table 87 – Primitives issued by DLL to DMPM .90
Table 88 – ALSM to DLL mapping.91

– 6 – PAS 61158-6-22 © IEC:2009(E)

INTERNATIONAL ELECTROTECHNICAL COMMISSION

____________
INDUSTRIAL COMMUNICATION NETWORKS –

FIELDBUS SPECIFICATIONS –
Part 6-22: Application layer protocol specification –

Type SNpTYPE elements
FOREWORD
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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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3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
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5) IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
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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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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.

A PAS is a technical specification not fulfilling the requirements for a standard, but made
available to the public.
IEC-PAS 61158-6-22 has been processed by subcommittee 65C: Industrial networks, of IEC
technical committee 65: Industrial-process measurement, control and automation.
The text of this PAS is based on the This PAS was approved for
following document: publication by the P-members of the
committee concerned as indicated in
the following document
Draft PAS Report on voting
65C/530/PAS 65C/534/RVD
Following publication of this PAS, which is a pre-standard publication, the technical committee
or subcommittee concerned may transform it into an International Standard.

PAS 61158-6-22 © IEC:2009(E) – 7 –

This PAS shall remain valid for an initial maximum period of 3 years starting from the

publication date. The validity may be extended for a single 3-year period, following which it

shall be revised to become another type of normative document, or shall be withdrawn.

The list of all the parts of the IEC 61158 series, under the general title Industrial

communication networks – Fieldbus specifications, can be found on the IEC web site.

– 8 – PAS 61158-6-22 © IEC:2009(E)

INTRODUCTION
This PAS contains an additional profile – SNpTYPE – which may be integrated into a future

new edition of the IEC 61158-6 series.

PAS 61158-6-22 © IEC:2009(E) – 9 –

INDUSTRIAL COMMUNICATION NETWORKS –

FIELDBUS SPECIFICATIONS –
Part 6-22: Application layer protocol specification –

Type SNpTYPE 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 part of IEC 61158-6 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 SNpTYPE 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 part of IEC 61158-6 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 part of IEC 61158-6 is to define the protocol provided to:
1) define the wire-representation of the service primitives defined in IEC/PAS 61158-5-22;
and
2) define the externally visible behavior associated with their transfer.

This part of IEC 61158-6 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
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

– 10 – PAS 61158-6-22 © IEC:2009(E)

in this part of IEC 61158-6 to provide access to the FAL to control certain aspects of its

operation.
1.2 Specifications
The principal objective of this part of IEC 61158-6 is to specify the syntax and behavior of the

application layer protocol that conveys the application layer services defined in

IEC/PAS 61158-5-22.
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 part of IEC 61158-6 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/PAS 61158-3-22, Industrial communication networks – Fieldbus specifications – Part 3-
SNpTYPE: Data-link layer service definition – Type SNpTYPE elements
IEC/PAS 61158-4-22, Industrial communication networks – Fieldbus specifications – Part 4-
SNpTYPE: Data-link layer protocol specification – Type SNpTYPE elements
IEC/PAS 61158-5-22, Industrial communication networks – Fieldbus specifications – Part 5–
SNpTYPE: Application layer service definition - Type SNpTYPE 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
ISO/IEC 9545, Information Technology – Open Systems Interconnection – Application Layer
structure
PAS 61158-6-22 © IEC:2009(E) – 11 –

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 Referenced terms and definitions

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
For the purposes of this document, the following terms as defined in ISO/IEC 8822 apply:
a) abstract syntax
b) presentation context
3.1.3 ISO/IEC 9545 terms
For the purposes of this document, the following terms as defined in ISO/IEC 9545 apply:
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 terms
For the purposes of this document, the following terms as defined in ISO/IEC 8824 apply:
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 – PAS 61158-6-22 © IEC:2009(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
3.2.15
error
discrepancy between a computed, observed or measured value or condition and the specified
or theoretically correct value or condition

PAS 61158-6-22 © IEC:2009(E) – 13 –

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
mapping parameters
set of values defining the correspondence between application objects and process data
objects
3.2.23
master clock
global time base for the PCS mechanism
3.2.24
message
ordered sequence of octets intended to convey data
3.2.25
message channel (MSC)
part of one or more frames, which is reserved for acyclic data
3.2.26
network
set of devices connected by some type of communication medium, including any intervening
repeaters, bridges, routers and lower-layer gateways
3.2.27
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
3.2.28
precise clock synchronization (PCS)
mechanism to synchronize clocks of RTFL devices and maintain a global time base

– 14 – PAS 61158-6-22 © IEC:2009(E)

3.2.29
process data
data designated to be transferred cyclically or acyclically for the purpose of processing

3.2.30
process data object
dedicated data object(s) designated to be transferred cyclically or acyclically for the purpose

of processing
3.2.31
protocol
convention about the data formats, time sequences, and error correction in the data exchange
of communication systems
3.2.32
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
3.2.33
real time frame line (RTFL)
communication model for communication with high real time requirements
3.2.34
real time frame network (RTFN)
communication model for communication with low real time requirements
3.2.35
round trip time
transmission time needed by a DLPDU from the RD to the last OD in forward and backward
direction
3.2.36
sub-index
sub-position of an individual element of an object within the object dictionary
3.2.37
timing signal
time-based indication of the occurrence of an event, commonly as an interrupt signal, used for
DL-user synchronization
3.2.38
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

PAS 61158-6-22 © IEC:2009(E) – 15 –

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
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
– 16 – PAS 61158-6-22 © IEC:2009(E)

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
RxPDO Receive PDO
SA Source address
SDO Service data object
SEF Standard Ethernet frame
StdErr Standard error output
StdIn Standard input
StdOut Standard output
PAS 61158-6-22 © IEC:2009(E) – 17 –

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/PAS 61158-5-22. The
protocol specification for each of the ASEs is defined in this part of IEC 61158-6.
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/PAS 61158-5-22. The service specification defines the services that are
provided by the ASE.
This part of IEC 61158-6 uses the descriptive conventions given in ISO/IEC 10731.
3.4.2 Abstract syntax conventions
The data type BYTE used within this part of IEC 61158-6 is of the type Unsigned8 as
specified in 5.2.
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.

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.
• Ind
...