IEC 61158-6-23:2023

Industrial communication networks - Fieldbus specifications - Part 6-23: Application layer protocol specification - Type 23 elements

IEC 61158-6-23:2023 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 23 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.

Réseaux de communication industriels - Spécifications des bus de terrain - Partie 6-23: Spécification du protocole de la couche application - Eléments de type 23

L'IEC 61158-6-23:2023 fournit des éléments communs pour les communications à temps critique ou non entre des programmes d’application dans un environnement et avec un matériel d’automation spécifiques aux bus de terrain de type 23. Le terme "à temps critique" est utilisé pour indiquer la présence d’une fenêtre temporelle, dans laquelle il est exigé de réaliser une ou plusieurs actions spécifiées selon un niveau défini de certitude. Tout manquement à réaliser ces actions dans la fenêtre de temps prévue risque de provoquer la défaillance des applications qui les demandent, avec le risque de mettre en danger l’équipement, l’usine, voire les personnes.

General Information

• Status: Published
• Publication Date: 23-Mar-2023
• ICS: 25.040.40 - Industrial process measurement and control
• ICS: 35.100.70 - Application layer
• ICS: 35.110 - Networking
• Technical Committee: SC 65C - Industrial networks
• Drafting Committee: WG 9 - TC 65/SC 65C/WG 9
• Current Stage: PPUB - Publication issued
• Start Date: 31-Mar-2023
• Completion Date: 24-Mar-2023

Relations

• Revises: IEC 61158-6-23:2019 - Industrial communication networks - Fieldbus specifications - Part 6-23: Application layer protocol specification - Type 23 elements
• Effective Date: 05-Sep-2023

Overview

IEC 61158-6-23:2023 - part of the IEC 61158 fieldbus series - defines the application layer protocol specification for Type 23 elements in industrial communication networks. It provides the common elements used for both basic time‑critical and non‑time‑critical messaging between application programs in automation environments. The standard describes syntax, message (PDU) types and semantic elements needed to implement interoperable application‑layer behavior on Type 23 fieldbus devices while addressing the requirement that some actions must complete within a defined time window to avoid operational or safety risks.

Key Topics and Technical Requirements

• Application layer protocol elements: Abstract syntax and encoding rules for FAL (Fieldbus Application Layer) PDUs, including types C, F, and T as defined in the document.
• FALPDU types and message sets: Detailed PDU families (examples listed in the standard) such as Connect, ConnectAck, Scan, Collect, Token, MyStatus, CyclicData, Persuasion, Setup, F‑Token, Transient, TestData and many SLMP (Seamless Message Protocol) related PDUs.
• Time‑critical vs non‑time‑critical messaging: Definitions and handling guidance where time windows impose deterministic delivery or action requirements.
• Data type assignments: Specifications for data types used by the application layer for Type 23 PDUs.
• Protocol syntax and state machines: Formal descriptions for encoding, state transitions and conventions (e.g., reserved bits, abstract syntax descriptions).
• Conformance and normative references: References to related ISO/IEC and IEC documents used for terms, encoding conventions and verification of conformance.

Practical Applications

• Implementing the application layer in Type 23 fieldbus devices (controllers, I/O modules, gateways).
• Designing deterministic messaging for industrial automation, process control and safety‑relevant applications where missing time windows could affect equipment or personnel.
• Developing device firmware and network stacks that must interoperate with other fieldbus nodes using the Type 23 application profile.
• Integrating SLMP‑based services, cyclic and acyclic data exchange, and PTP (Precision Time Protocol) related messaging referenced in the PDU lists.

Who Should Use This Standard

• Industrial automation engineers and control system architects
• Device manufacturers and firmware developers for fieldbus equipment
• System integrators and control panel designers
• Test and conformance labs validating Type 23 implementations
• Safety and functional‑safety specialists concerned with time‑critical messaging

Related Standards

• Other parts of the IEC 61158 family (fieldbus specifications)
• Referenced documents such as ISO/IEC 7498‑1 and ISO/IEC 8822 for networking terminology and layer concepts

Keywords: IEC 61158-6-23, fieldbus, application layer protocol, Type 23, industrial communication networks, time-critical messaging, FALPDU, SLMP, automation.

Standards Content (Sample)

IEC 61158-6-23 ®
Edition 3.0 2023-03
INTERNATIONAL
STANDARD
Industrial communication networks – Fieldbus specifications –
Part 6-23: Application layer protocol specification – Type 23 elements

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IEC 61158-6-23 ®
Edition 3.0 2023-03
INTERNATIONAL
STANDARD
Industrial communication networks – Fieldbus specifications –

Part 6-23: Application layer protocol specification – Type 23 elements

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 25.040.40; 35.100.70; 35.110 ISBN 978-2-8322-6641-0

– 2 – IEC 61158-6-23:2023 © IEC 2023
CONTENTS
FOREWORD . 14
INTRODUCTION . 16
1 Scope . 17
1.1 General . 17
1.2 Specifications . 18
1.3 Conformance . 18
2 Normative references . 18
3 Terms, definitions, symbols, abbreviated terms and conventions . 19
3.1 Referenced terms and definitions . 19
3.1.1 ISO/IEC 7498-1 terms . 19
3.1.2 ISO/IEC 8822 terms . 19
3.1.3 IEC 61158-1 terms . 19
3.2 Additional Type 23 terms and definitions . 19
3.3 Symbols and abbreviated terms . 22
3.4 Conventions . 23
3.4.1 General concept . 23
3.4.2 Convention for the encoding of reserved bits and octets . 23
3.4.3 Conventions for abstract syntax description . 23
3.4.4 Conventions for bit description in octets . 23
3.4.5 Conventions for state machine descriptions . 24
4 FAL syntax description . 25
4.1 FALPDU type C abstract syntax . 25
4.1.1 Basic abstract syntax . 25
4.1.2 Connect-PDU . 26
4.1.3 ConnectAck-PDU . 26
4.1.4 Scan-PDU . 26
4.1.5 Collect-PDU . 27
4.1.6 Select-PDU . 27
4.1.7 Launch-PDU . 27
4.1.8 Token-PDU . 27
4.1.9 MyStatus-PDU . 28
4.1.10 Transient1-PDU . 28
4.1.11 Dummy-PDU . 29
4.1.12 Transient2-PDU . 29
4.1.13 NTNTest-PDU . 29
4.1.14 CyclicDataW-PDU. 30
4.1.15 CyclicDataB-PDU . 30
4.1.16 CyclicDataOut1-PDU . 30
4.1.17 CyclicDataOut2-PDU . 31
4.1.18 CyclicDataIn1-PDU . 31
4.1.19 CyclicDataIn2-PDU . 31
4.2 FALPDU type F abstract syntax . 32
4.2.1 Basic abstract syntax . 32
4.2.2 Persuasion-PDU . 33
4.2.3 TestData-PDU . 34
4.2.4 TestDataAck-PDU. 34
4.2.5 Setup-PDU . 35

4.2.6 SetupAck-PDU . 35
4.2.7 F-Token-PDU . 36
4.2.8 F-MyStatus-PDU . 36
4.2.9 Measure-PDU . 36
4.2.10 F-Offset-PDU . 37
4.2.11 F-Update-PDU . 37
4.2.12 F-CyclicData-PDU . 37
4.2.13 Transient1-PDU . 37
4.2.14 TransientAck-PDU . 41
4.2.15 Transient2-PDU . 42
4.2.16 ParamCheck-PDU . 42
4.2.17 Parameter-PDU . 43
4.2.18 Timer-PDU . 44
4.3 Data type assignments for type C . 45
4.4 Data type assignments for type F . 46
4.5 FALPDU type T abstract syntax . 47
4.5.1 Basic abstract syntax . 47
4.5.2 CyclicM-PDU . 50
4.5.3 CyclicS-PDU . 50
4.5.4 CyclicMs-PDU . 50
4.5.5 CyclicSs-PDU . 51
4.5.6 AcyclicPriority-PDU . 52
4.5.7 AcyclicDetection-PDU . 52
4.5.8 AcyclicDetectionAck-PDU . 53
4.5.9 AcyclicTestDataHeader . 54
4.5.10 AcyclicTestDataHeader . 55
4.5.11 AcyclicData-PDU . 55
4.5.12 PtpSync-PDU . 55
4.5.13 PtpPdelayReq-PDU . 55
4.5.14 PtpPdelayResp-PDU. 55
4.5.15 PtpFollowUp-PDU . 56
4.5.16 PtpPdelayRespFollowUp-PDU . 56
4.5.17 PtpAnnounce-PDU . 56
4.5.18 SlmpIPAddressSet-PDU . 56
4.5.19 SlmpNetworkConfigMain-PDU . 56
4.5.20 SlmpNetworkConfigTslt-PDU . 56
4.5.21 SlmpNotification-PDU . 56
4.5.22 SlmpMasterConfig-PDU . 57
4.5.23 SlmpSlaveConfig-PDU . 57
4.5.24 SlmpCyclicConfigMain-PDU . 57
4.5.25 SlmpCyclicConfigTrnSubPayload-PDU . 57
4.5.26 SlmpCyclicConfigRcvSubPayload-PDU . 57
4.5.27 SlmpCyclicConfigRcvSrcInfo-PDU . 58
4.5.28 SlmpLinkDevicePrmWrite-PDU . 58
4.5.29 SlmpLinkDevicePrmWriteCheckRequest-PDU . 58
4.5.30 SlmpLinkDevicePrmWriteCheckResponse-PDU . 58
4.5.31 SlmpNMTStateUpload-PDU . 58
4.5.32 SlmpNMTStateDownload-PDU . 59
4.5.33 SlmpReadObject-PDU . 59

– 4 – IEC 61158-6-23:2023 © IEC 2023
4.5.34 SlmpWriteObject-PDU . 59
4.5.35 SlmpObjectSubIDReadBlock-PDU . 59
4.5.36 SlmpObjectSubIDWriteBlock-PDU . 59
4.5.37 SlmpGetODList-PDU . 59
4.5.38 SlmpGetObjectDescription-PDU . 60
4.5.39 SlmpGetEntryDescription-PDU . 60
4.5.40 SlmpStopOwnStationCyclic-PDU . 60
4.5.41 SlmpStartOwnStationCyclic-PDU . 60
4.5.42 SlmpStopOtherStationsCyclic-PDU . 60
4.5.43 SlmpStartOtherStationsCyclic-PDU . 60
4.5.44 SlmpAllParameterGet-PDU . 61
4.5.45 SlmpParameterGet-PDU . 61
4.5.46 SlmpAllParameterSizeGet-PDU . 61
4.5.47 SlmpParameterSizeGet-PDU . 61
4.5.48 SlmpStationSubIDListGet-PDU . 61
4.5.49 SlmpDeviceIdentificationInfoGet-PDU . 61
4.5.50 SlmpDataMonitoring-PDU . 62
4.5.51 SlmpAllParameterSet-PDU . 62
4.5.52 SlmpParameterSet-PDU . 62
4.5.53 SlmpParameterVersionCheck-PDU . 62
4.5.54 SlmpDeviceIdentificationInfoCompare-PDU . 62
4.5.55 SlmpNodeSearch-PDU . 62
4.5.56 SlmpIPAddressSet-PDU . 63
4.5.57 SlmpDeviceInfoCompare-PDU . 63
4.5.58 SlmpParameterGet-PDU . 63
4.5.59 SlmpParameterSet-PDU . 63
4.5.60 SlmpParameterSetStart-PDU . 63
4.5.61 SlmpParameterSetEnd-PDU . 63
4.5.62 SlmpVerifyCheckCode-PDU . 64
4.5.63 SlmpOutputMapFileNameGet-PDU . 64
4.5.64 SlmpNewFile-PDU . 64
4.5.65 SlmpParameterSetCancel-PDU . 64
4.5.66 SlmpOpenFile-PDU . 64
4.5.67 SlmpCloseFile-PDU . 64
4.5.68 SlmpReadFile-PDU . 65
4.5.69 SlmpWriteFile-PDU . 65
4.5.70 SlmpStatusRead-PDU . 65
4.5.71 SlmpCommunicationSettingGet-PDU . 65
4.5.72 SlmpGetDeviceInfo-PDU . 65
4.5.73 SlmpGetBackupListFileName-PDU . 65
4.5.74 SlmpStartBackup-PDU . 66
4.5.75 SlmpEndBackup-PDU . 66
4.5.76 SlmpCheckRestoreVersion-PDU . 66
4.5.77 SlmpStartRestore-PDU . 66
4.5.78 SlmpEndRestore-PDU . 66
4.5.79 SlmpStatusRead2-PDU. 66
4.5.80 SlmpReqSearchNode-PDU . 67
4.5.81 SlmpGetSearchNodeState-PDU . 67
4.5.82 SlmpGetNodeList-PDU . 67

4.5.83 SlmpReqSetIPAddress-PDU . 67
4.5.84 SlmpSearchPrmControlStation-PDU . 67
4.5.85 SlmpRequestRestore-PDU . 68
4.5.86 SlmpCheckPrmDelivery-PDU . 68
4.5.87 SlmpRsvStationConfigTemporaryRelease-PDU . 68
4.5.88 SlmpRsvStationConfig-PDU . 68
4.5.89 SlmpGetEventNum-PDU . 68
4.5.90 SlmpGetEventHistory-PDU . 69
4.5.91 SlmpClearEventHistory-PDU . 69
4.5.92 SlmpClockOffsetDataSend-PDU . 69
4.5.93 SlmpSetWatchdogCounterInfo-PDU . 69
4.5.94 SlmpWatchdogCounterOffsetConfig-PDU . 69
4.5.95 SlmpRemoteReset-PDU . 69
4.5.96 SlmpGetCommunicationSet-PDU . 70
4.5.97 SlmpGetStationSubIDList-PDU . 70
4.5.98 SlmpGetDeviceInfo-PDU . 70
4.5.99 SlmpStartBackup-PDU . 70
4.5.100 SlmpEndBackup-PDU . 70
4.5.101 SlmpRequestBackup-PDU . 70
4.5.102 SlmpGetBackupPrm-PDU . 71
4.5.103 SlmpCheckRestore-PDU . 71
4.5.104 SlmpStartRestore-PDU . 71
4.5.105 SlmpEndRestore-PDU . 71
4.5.106 SlmpSetBackupPrm-PDU . 71
4.5.107 SlmpLinkupSpeed-PDU . 71
4.5.108 SlmpNodeIndication-PDU . 72
4.6 Data type assignments for type T . 72
5 FAL transfer syntax . 72
5.1 Encoding rules . 72
5.1.1 Unsigned encoding . 72
5.1.2 Octet string encoding . 72
5.1.3 SEQUENCE encoding . 72
5.1.4 LOctetString encoding . 72
5.2 FALPDU type C elements encoding . 73
5.2.1 FALARHeader . 73
5.2.2 Connect-PDU . 75
5.2.3 ConnectAck-PDU . 76
5.2.4 Scan-PDU . 76
5.2.5 Collect-PDU . 77
5.2.6 Select-PDU . 79
5.2.7 Launch-PDU . 80
5.2.8 Token-PDU . 80
5.2.9 MyStatus-PDU . 80
5.2.10 Transient1-PDU . 82
5.2.11 Dummy-PDU . 86
5.2.12 Transient2-PDU . 87
5.2.13 NTNTest-PDU . 98
5.2.14 CyclicDataW-PDU. 98
5.2.15 CyclicDataB-PDU . 99

– 6 – IEC 61158-6-23:2023 © IEC 2023
5.2.16 CyclicDataOut1-PDU . 100
5.2.17 CyclicDataOut2-PDU . 100
5.2.18 CyclicDataIn1-PDU . 101
5.2.19 CyclicDataIn2-PDU . 102
5.3 FALPDU type F elements encoding . 103
5.3.1 FALARHeader . 103
5.3.2 Persuasion-PDU . 108
5.3.3 TestData-PDU . 109
5.3.4 TestDataAck-PDU. 109
5.3.5 Setup-PDU . 111
5.3.6 SetupAck-PDU . 113
5.3.7 F-Token-PDU . 114
5.3.8 F-Measure-PDU . 115
5.3.9 F-Offset-PDU . 116
5.3.10 F-Update-PDU . 116
5.3.11 F-MyStatus-PDU . 116
5.3.12 F-CyclicData-PDU . 122
5.3.13 Transient1-PDU . 123
5.3.14 TransientAck-PDU . 128
5.3.15 Transient2-PDU . 129
5.3.16 ParamCheck-PDU . 132
5.3.17 Parameter-PDU . 133
5.3.18 Timer-PDU . 140
5.4 FALPDU type T elements encoding . 141
5.4.1 CyclicM-PDU . 141
5.4.2 CyclicS-PDU . 144
5.4.3 CyclicMs-PDU . 146
5.4.4 CyclicSs-PDU . 147
5.4.5 AcyclicPriority-PDU . 148
5.4.6 AcyclicDetection-PDU . 150
5.4.7 AcyclicDetectionAck-PDU . 151
5.4.8 AcyclicTestData-PDU . 157
5.4.9 AcyclicTestDataAck-PDU . 160
5.4.10 AcyclicData-PDU . 162
5.4.11 Ptp-PDU . 162
5.4.12 IpData-PDU . 164
6 Structure of the FAL protocol state machine . 164
7 FAL service protocol machine (FSPM) . 165
7.1 Overview. 165
7.2 FSPM type C . 165
7.2.1 Overview . 165
7.2.2 FSPM . 166
7.3 FSPM type F . 169
7.3.1 Overview . 169
7.3.2 FSPM . 171
7.4 FSPM type T . 176
7.4.1 Overview . 176
7.4.2 FSPM State Machine . 177
8 Application relationship protocol machine (ARPM) . 181

8.1 ARPM type C . 181
8.1.1 Overview . 181
8.1.2 Acyclic transmission . 182
8.1.3 Cyclic transmission . 183
8.1.4 Connection control . 188
8.1.5 Common parameter dist . 227
8.2 ARPM type F . 232
8.2.1 Overview . 232
8.2.2 Acyclic transmission . 233
8.2.3 Cyclic transmission . 235
8.2.4 Channel control . 238
8.2.5 Parameter dist . 278
8.2.6 Synchronous trigger. 282
8.2.7 Timer . 283
8.2.8 Measure transmission . 284
8.3 ARPM type T . 289
8.3.1 Overview . 289
8.3.2 Cyclic Transmission . 289
8.3.3 Acyclic Transmission . 291
8.3.4 Channel Control . 294
8.3.5 TimeSync Control . 297
8.3.6 IPTrans Control . 299
8.3.7 Handler. 300
9 DLL mapping protocol machine (DMPM) . 305
9.1 DMPM type C . 305
9.2 DMPM type F . 306
9.3 DMPM type T . 307
Bibliography . 309

Figure 1 – Bit description in octets . 24
Figure 2 – Structure for memory access information retrieve response . 90
Figure 3 – Attribute definitions . 90
Figure 4 – Access code definitions . 91
Figure 5 – Structure for RUN request . 92
Figure 6 – Structure for RUN response . 93
Figure 7 – Structure for STOP request . 93
Figure 8 – Structure for STOP response . 93
Figure 9 – Structure for batch memory read request . 94
Figure 10 – Structure for batch memory read response . 94
Figure 11 – Structure for random memory read request . 95
Figure 12 – Structure for random memory read response . 95
Figure 13 – Structure for batch memory write request . 96
Figure 14 – Structure for batch memory write response . 96
Figure 15 – Structure for random memory write request . 97
Figure 16 – Structure for random memory write response . 97
Figure 17 – Relationships between protocol machines . 165

– 8 – IEC 61158-6-23:2023 © IEC 2023
Figure 18 – Structure of FSPM C . 166
Figure 19 – Structure of FSPM F. 169
Figure 20 – Structure of FSPM T. 176
Figure 21 – Structure of ARPM C . 181
Figure 22 – Structure of ARPM F . 232
Figure 23 – Structure of ARPM T . 289
Figure 24 – Structure of type C DMPM . 305
Figure 25 – Structure of type F DMPM . 306
Figure 26 – Structure of type T DMPM . 307

Table 1 – State machine description elements . 24
Table 2 – Description of state machine elements . 24
Table 3 – Conventions used in state machines . 25
Table 4 – afFType . 73
Table 5 – priority . 74
Table 6 – portChoice. 75
Table 7 – portCheckResult . 76
Table 8 – dstPortInfo . 76
Table 9 – scanState . 76
Table 10 – nodeType . 77
Table 11 – loopState . 78
Table 12 – Cyclic status . 78
Table 13 – Parameter setting mode . 78
Table 14 – opState . 81
Table 15 – errorState . 81
Table 16 – Data type. 83
Table 17 – CPW. 83
Table 18 – CPWC . 84
Table 19 – CPWCR . 84
Table 20 – cmParam . 84
Table 21 – Details of param area . 85
Table 22 – Details of application parameters . 85
Table 23 – Details of LB/LW CM area and LB/LW CM additional area . 86
Table 24 – Details of LX/LY CM 1 area and LX/LY CM 2 area . 86
Table 25 – Destination module flag . 88
Table 26 – Command types . 89
Table 27 – Access codes of network module memory . 91
Table 28 – Access codes of controller memory . 92
Table 29 – byteValidity . 98
Table 30 – afFType . 104
Table 31 – dataType . 105
Table 32 – varField . 106
Table 33 – nodeType . 107

Table 34 – ProtocolVerType . 108
Table 35 – Link status . 111
Table 36 – Port enable/disable specification . 112
Table 37 – Cyclic transmission parameter hold status . 118
Table 38 – Detailed application operation status . 119
Table 39 – Error detection status . 119
Table 40 – Slave-specific event reception status . 121
Table 41 – dataSupType of dataType (0x07) . 124
Table 42 – FieldSpecificTransient opHeader . 124
Table 43 – command (dataType: 0x07, dataSubType: 0x0002) . 125
Table 44 – subCommand type for each command type . 125
Table 45 – Structure of Deliver node information . 125
Table 46 – Structure of Deliver node information – message . 126
Table 47 – Structure of Get statistical information response . 127
Table 48 – Structure of Acquisition of node details response . 128
Table 49 – Execution module specification. 130
Table 50 – Command type .
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