IEC 61158-6-2:2019

IEC 61158-6-2 ®
Edition 4.0 2019-06
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Industrial communication networks – Fieldbus specifications –
Part 6-2: Application layer protocol specification – Type 2 elements

Réseaux de communication industriels – Spécifications des bus de terrain –
Partie 6-2: Spécification du protocole de la couche liaison de données –
Eléments de type 2
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IEC 61158-6-2 ®
Edition 4.0 2019-06
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Industrial communication networks – Fieldbus specifications –

Part 6-2: Application layer protocol specification – Type 2 elements

Réseaux de communication industriels – Spécifications des bus de terrain –

Partie 6-2: Spécification du protocole de la couche liaison de données –

Eléments de type 2
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 25.040.40; 35.100.70; 35.110 ISBN 978-2-8322-9699-8

– 2 – IEC 61158-6-2:2019 © IEC 2019
CONTENTS
FOREWORD . 14
INTRODUCTION . 16
1 Scope . 17
1.1 General . 17
1.2 Specifications . 17
1.3 Conformance . 18
2 Normative references . 18
3 Terms, definitions, symbols, abbreviated terms and conventions . 20
3.1 Terms and definitions from other ISO/IEC standards . 20
3.1.1 Terms and definitions from ISO/IEC 7498-1 . 20
3.1.2 Terms and definitions from ISO/IEC 9545 . 21
3.1.3 Terms and definitions from ISO/IEC 8824-1 . 21
3.1.4 Terms and definitions from ISO/IEC 8825-1 . 22
3.2 Terms and definitions from IEC 61158-5-2 . 22
3.3 Additional terms and definitions . 22
3.4 Abbreviated terms and symbols . 29
3.5 Conventions . 29
3.5.1 General concept . 29
3.5.2 Attribute specification . 30
3.5.3 Common services . 30
3.5.4 State machine conventions . 34
4 Abstract syntax . 35
4.1 FAL PDU abstract syntax . 35
4.1.1 General . 35
4.1.2 PDU structure . 36
4.1.3 UCMM_PDUs . 38
4.1.4 Transport_Headers . 40
4.1.5 CM_PDUs . 43
4.1.6 CM PDU components . 57
4.1.7 MR headers . 66
4.1.8 OM_Service_PDU . 67
4.1.9 Message and connection paths . 122
4.1.10 Class, attribute and service codes . 137
4.1.11 Error codes . 143
4.2 Data abstract syntax specification . 157
4.2.1 Transport format specification . 157
4.2.2 Abstract syntax notation . 157
4.2.3 Control network data specification . 158
4.2.4 Data type specification / dictionaries . 160
4.3 Encapsulation abstract syntax . 162
4.3.1 Encapsulation protocol . 162
4.3.2 Command descriptions . 165
4.3.3 Common packet format . 177
5 Transfer syntax . 181
5.1 Compact encoding . 181
5.1.1 Encoding rules . 181

5.1.2 Encoding constraints . 182
5.1.3 Examples. 182
5.2 Data type reporting . 188
5.2.1 Object data representation. 188
5.2.2 Elementary data type reporting . 189
5.2.3 Constructed data type reporting . 190
6 Structure of FAL protocol state machines . 196
7 AP-Context state machine . 196
7.1 Overview. 196
7.2 Connection object state machine . 196
7.2.1 I/O Connection instance behavior . 196
7.2.2 Bridged Connection instance behavior . 200
7.2.3 Explicit Messaging Connection instance behavior . 201
8 FAL service protocol machine (FSPM) . 204
8.1 General . 204
8.2 Primitive definitions . 204
8.3 Parameters of primitives . 209
8.4 FSPM state machines . 209
9 Application relationship protocol machines (ARPMs) . 210
9.1 General . 210
9.2 Connection-less ARPM (UCMM) . 210
9.2.1 General . 210
9.2.2 Primitive definitions . 210
9.2.3 Parameters of primitives . 211
9.2.4 UCMM state machines . 212
9.2.5 Examples of UCMM sequences . 217
9.2.6 Management UCMM . 219
9.3 Connection-oriented ARPMs (transports) . 220
9.3.1 Transport PDU buffer . 220
9.3.2 Transport classes . 220
9.3.3 Common primitive definitions . 221
9.3.4 Parameters of common primitives . 222
9.3.5 Transport state machines – class 0 . 222
9.3.6 Transport state machines – class 1 . 226
9.3.7 Transport state machines – class 2 . 231
9.3.8 Transport state machines – class 3 . 239
9.3.9 Transport state machines – classes 4, 5, 6 . 249
9.3.10 Transport state machines – class 4 . 249
9.3.11 Transport state machines – class 5 . 249
9.3.12 Transport state machines – class 6 . 249
10 DLL mapping protocol machine 1 (DMPM 1) . 249
10.1 General . 249
10.2 Link producer . 250
10.3 Link consumer . 250
10.4 Primitive definitions . 250
10.4.1 Primitives exchanged between DMPM and ARPM . 250
10.4.2 Parameters of ARPM/DMPM primitives . 250
10.4.3 Primitives exchanged between data-link layer and DMPM . 251

– 4 – IEC 61158-6-2:2019 © IEC 2019
10.4.4 Parameters of DMPM/Data-link Layer primitives . 251
10.4.5 Network connection ID . 252
10.5 DMPM state machine . 253
10.5.1 DMPM states . 253
10.5.2 Functions used by DMPM . 254
10.6 Data-link Layer service selection. 254
11 DLL mapping protocol machine 2 (DMPM 2) . 254
11.1 General . 254
11.2 Mapping of UCMM PDUs . 255
11.2.1 General . 255
11.2.2 Common requirements for Connection Manager PDU’s . 256
11.2.3 Forward_open PDU for class 2 and class 3 connections . 258
11.2.4 Forward_open for class 0 and class 1 connections . 258
11.2.5 Forward_close . 262
11.3 Mapping of transport class 0 and class 1 PDUs. 263
11.3.1 Class 0 and class 1 PDUs. 263
11.3.2 No dependency on TCP connections . 263
11.3.3 Class 0 and class 1 packet ordering . 263
11.3.4 Screening incoming connected data . 264
11.4 Mapping of transport class 2 and class 3 PDU’s . 264
11.5 Mapping of transport classes 4 to 6. 265
11.6 IGMP Usage . 265
11.6.1 Background (informative) . 265
11.6.2 IGMP Membership Report messages . 266
11.6.3 IGMP Leave Group messages . 266
11.7 Quality of Service (QoS) for CP 2/2 messages . 267
11.7.1 Overview . 267
11.7.2 DSCP format . 267
11.7.3 IEEE 802.1D/IEEE 802.Q format . 268
11.7.4 Mapping CPF 2 traffic to DSCP and IEEE 802.1D . 268
11.7.5 CP 2/2 usage of DSCP . 269
11.7.6 CP 2/2 usage of IEEE 802.1D/IEEE 802.1Q . 269
11.7.7 User considerations with IEEE 802.1D/IEEE 802.1Q . 269
11.8 Management of an encapsulation session . 270
11.8.1 Phases of an encapsulation session . 270
11.8.2 Establishing a session . 270
11.8.3 Terminating a session . 270
11.8.4 Maintaining a session . 270
11.8.5 TCP connection management . 271
12 DLL mapping protocol machine 3 (DMPM 3) . 271
Bibliography . 272

Figure 1 – Attribute table format and terms . 30
Figure 2 – Service request/response parameter . 30
Figure 3 – Example of an STD . 34
Figure 4 – Network connection parameters . 58
Figure 5 – Priority/Tick_time bit definition . 61
Figure 6 – Member ID/EX description (WORD). 75

Figure 7 – Transport Class Trigger attribute . 110
Figure 8 – CP2/3_initial_comm_characteristics attribute format . 114
Figure 9 – Segment type . 123
Figure 10 – Port segment . 124
Figure 11 – Logical segment encoding . 126
Figure 12 – Extended network segment . 132
Figure 13 – Symbolic segment encoding . 133
Figure 14 – Encapsulation message . 162
Figure 15 – FixedLengthBitString compact encoding bit placement rules . 185
Figure 16 – Example compact encoding of a SWORD FixedLengthBitString . 186
Figure 17 – Example compact encoding of a WORD FixedLengthBitString . 186
Figure 18 – Example compact encoding of a DWORD FixedLengthBitString . 186
Figure 19 – Example compact encoding of a LWORD FixedLengthBitString . 186
Figure 20 – Example 1 of formal encoding of a structure type specification . 191
Figure 21 – Example 2 of formal encoding of a structure type specification . 191
Figure 22 – Example 3 of formal encoding of a handle structure type specification . 192
Figure 23 – Example 4 of formal encoding of a handle structure type specification . 192
Figure 24 – Example 5 of abbreviated encoding of a structure type specification . 193
Figure 25 – Example 1 of formal encoding of an array type specification. 194
Figure 26 – Example 2 of formal encoding of an array type specification. 194
Figure 27 – Example 1 of abbreviated encoding of an array type specification . 195
Figure 28 – Example 2 of abbreviated encoding of an array type specification . 195
Figure 29 – I/O Connection object state transition diagram . 196
Figure 30 – Bridged Connection object state transition diagram . 200
Figure 31 – Explicit Messaging Connection object state transition diagram . 202
Figure 32 – State transition diagram of UCMM client9 . 212
Figure 33 – State transition diagram of high–end UCMM server . 214
Figure 34 – State transition diagram of low–end UCMM server . 216
Figure 35 – Sequence diagram for a UCMM with one outstanding message . 218
Figure 36 – Sequence diagram for a UCMM with multiple outstanding messages . 219
Figure 37 – TPDU buffer . 220
Figure 38 – Data flow diagram using a client transport class 0 and server transport
class 0 . 223
Figure 39 – Sequence diagram of data transfer using transport class 0 . 223
Figure 40 – Class 0 client STD . 224
Figure 41 – Class 0 server STD . 225
Figure 42 – Data flow diagram using client transport class 1 and server transport

class 1 . 226
Figure 43 – Sequence diagram of data transfer using client transport class 1 and
server transport class 1 . 227
Figure 44 – Class 1 client STD . 229
Figure 45 – Class 1 server STD . 230
Figure 46 – Data flow diagram using client transport class 2 and server transport
class 2 . 232

– 6 – IEC 61158-6-2:2019 © IEC 2019
Figure 47 – Diagram of data transfer using client transport class 2 and server transport
class 2 without returned data . 233
Figure 48 – Sequence diagram of data transfer using client transport class 2 and

server transport class 2 with returned data . 234
Figure 49 – Class 2 client STD . 235
Figure 50 – Class 2 server STD . 237
Figure 51 – Data flow diagram using client transport class 3 and server transport
class 3 . 240
Figure 52 – Sequence diagram of data transfer using client transport class 3 and
server transport class 3 without returned data . 241
Figure 53 – Sequence diagram of data transfer using client transport class 3 and

server transport class 3 with returned data . 242
Figure 54 – Class 3 client STD . 244
Figure 55 – Class 3 server STD . 247
Figure 56 – Data flow diagram for a link producer and consumer . 249
Figure 57 – State transition diagram for a link producer . 253
Figure 58 – State transition diagram for a link consumer . 254
Figure 59 – DS field in the IP header . 268
Figure 60 – IEEE 802.1Q tagged frame . 268

Table 1 – Get_Attributes_All response service rules . 31
Table 2 – Example class level object/service specific response data of
Get_Attributes_All . 31
Table 3 – Example Get_Attributes_All data array method . 32
Table 4 – Set_Attributes_All request service rules . 33
Table 5 – Example Set_Attributes_All attribute ordering method . 33
Table 6 – Example Set_Attributes_All data array method . 33
Table 7 – State event matrix format . 35
Table 8 – Example state event matrix . 35
Table 9 – UCMM_PDU header format . 39
Table 10 – UCMM command codes . 39
Table 11 – Transport class 0 header . 40
Table 12 – Transport class 1 header . 40
Table 13 – Transport class 2 header . 40
Table 14 – Transport class 3 header . 40
Table 15 – Real-time data header – exclusive owner . 41
Table 16 – Real-time data header– redundant owner . 41
Table 17 – Forward_Open request format . 46
Table 18 – Forward_Open_Good response format . 46
Table 19 – Forward_Open_Bad response format . 47
Table 20 – Large_Forward_Open request format . 48
Table 21 – Large_Forward_Open_Good response format . 48
Table 22 – Large_Forward_Open_Bad response format . 49
Table 23 – Forward_Close request format. 50
Table 24 – Forward_Close_Good response format . 50

Table 25 – Forward_Close_Bad response format . 51
Table 26 – Unconnected_Send request format . 51
Table 27 – Unconnected_Send_Good response format . 52
Table 28 – Unconnected_Send_Bad response format . 53
Table 29 – Unconnected_Send request format (modified) . 54
Table 30 – Unconnected_Send_Good response format (modified) . 54
Table 31 – Unconnected_Send_Bad response format (modified) . 55
Table 32 – Get_Connection_Data request format . 55
Table 33 – Get_Connection_Data response format . 55
Table 34 – Search_Connection_Data request format . 56
Table 35 – Get_Connection_Owner request format . 57
Table 36 – Get_Connection_Owner response format . 57
Table 37 – Time-out multiplier . 60
Table 38 – Tick time units . 61
Table 39 – Encoded application path ordering. 65
Table 40 – Transport class, trigger and Is_Server format . 66
Table 41 – MR_Request_Header format . 66
Table 42 – MR_Response_Header format . 67
Table 43 – Structure of Get_Attributes_All_ResponsePDU body . 67
Table 44 – Structure of Set_Attributes_All_RequestPDU body . 68
Table 45 – Structure of Get_Attribute_List_RequestPDU body . 68
Table 46 – Structure of Get_Attribute_List_ResponsePDU body . 68
Table 47 – Structure of Set_Attribute_List_RequestPDU body . 68
Table 48 – Structure of Set_Attribute_List_ResponsePDU body . 69
Table 49 – Structure of Reset_RequestPDU body . 69
Table 50 – Structure of Reset_ResponsePDU body . 69
Table 51 – Structure of Start_RequestPDU body . 69
Table 52 – Structure of Start_ResponsePDU body . 69
Table 53 – Structure of Stop_RequestPDU body . 70
Table 54 – Structure of Stop_ResponsePDU body . 70
Table 55 – Structure of Create_RequestPDU body . 70
Table 56 – Structure of Create_ResponsePDU body . 70
Table 57 – Structure of Delete_RequestPDU body . 70
Table 58 – Structure of Delete_ResponsePDU body . 70
Table 59 – Structure of Get_Attribute_Single_ResponsePDU body . 71
Table 60 – Structure of Set_Attribute_Single_RequestPDU body . 71
Table 61 – Structure of Set_Attribute_Single_ResponsePDU body . 71
Table 62 – Structure of Find_Next_Object_Instance_RequestPDU body . 71
Table 63 – Structure of Find_Next_Object_Instance_ResponsePDU body . 72
Table 64 – Structure of Apply_Attributes_RequestPDU body . 72
Table 65 – Structure of Apply_Attributes_ResponsePDU body . 72
Table 66 – Structure of Save_RequestPDU body . 72
Table 67 – Structure of Save_ResponsePDU body . 72

– 8 – IEC 61158-6-2:2019 © IEC 2019
Table 68 – Structure of Restore_RequestPDU body . 73
Table 69 – Structure of Restore_ResponsePDU body . 73
Table 70 – Structure of Get_Member_ResponsePDU body . 73
Table 71 – Structure of Set_Member_RequestPDU body . 73
Table 72 – Structure of Set_Member_ResponsePDU body . 73
Table 73 – Structure of Insert_Member_RequestPDU body . 74
Table 74 – Structure of Insert_Member_ResponsePDU body . 74
Table 75 – Structure of Remove_Member_ResponsePDU body . 74
Table 76 – Common structure of _Member_RequestPDU body (basic format) . 75
Table 77 – Common structure of _Member_ResponsePDU body (basic format) . 75
Table 78 – Common structure of _Member_RequestPDU body (extended format) . 76
Table 79 – Common structure of _Member_ResponsePDU body (extended format) . 76
Table 80 – Extended Protocol ID. 76
Table 81 – Structure of _Member_RequestPDU body (Multiple Sequential Members) . 77
Table 82 – Structure of _Member_ResponsePDU body (Multiple Sequential Members) . 77
Table 83 – Structure of _Member_RequestPDU body (International String Selection) . 78
Table 84 – Structure of _Member_ResponsePDU body (International String Selection) . 78
Table 85 – Structure of Group_Sync_RequestPDU body . 78
Table 86 – Structure of Group_Sync_ResponsePDU body . 78
Table 87 – Structure of Multiple_Service_Packet_RequestPDU body . 79
Table 88 – Structure of Multiple_Service_Packet_ResponsePDU body . 79
Table 89 – Identity object class attributes . 80
Table 90 – Identity object instance attributes . 80
Table 91 – Identity object bit definitions for status instance attribute . 81
Table 92 – Default values for extended device status field (bits 4 to 7) of status
instance attribute . 82
Table 93 – Identity object bit definitions for protection mode instance attribute . 82
Table 94 – Class level object/service specific response data of Get_Attributes_All . 82
Table 95 – Instance level object/service specific response data of Get_Attributes_All . 83
Table 96 – Object-specific request parameter for Reset . 83
Table 97 – Reset service parameter values . 84
Table 98 – Communication link attributes that shall be preserved . 84
Table 99 – Structure of Flash_LEDs_RequestPDU body . 84
Table 100 – Message Router object class attributes . 85
Table 101 – Message Router object instance attributes . 85
Table 102 – Class level object/service specific response data of Get_Attributes_All . 85
Table 103 – Instance level object/service specific response data of Get_Attributes_All . 86
Table 104 – Structure of Symbolic_Translation_RequestPDU body . 86
Table 105 – Structure of Symbolic_Translation_ResponsePDU body . 86
Table 106 – Object specific status for Symbolic_Translation service . 86
Table 107 – Assembly object class attributes . 87
Table 108 – Assembly object instance attributes . 87
Table 109 – Assembly Instance ID ranges . 88

Table 110 – Acknowledge Handler object class attributes . 88
Table 111 – Acknowledge Handler object instance attributes . 89
Table 112 – Structure of Add_AckData_Path_RequestPDU body . 89
Table 113 – Structure of Remove_AckData_Path_RequestPDU body . 89
Table 114 – Time Sync object class attributes . 90
Table 115 – Time Sync object instance attributes . 90
Table 116 – ClockIdentity encoding for different network implementations . 94
Table 117 – ClockClass values . 94
Table 118 – TimeAccuracy values . 94
Table 119 – TimePropertyFlags bit values . 95
Table 120 – TimeSource values . 95
Table 121 – Types of Clock . 96
Table 122 – Network protocol to PortPhysicalAddressInfo mapping . 96
Table 123 – Parameter object class attributes . 97
Table 124 – Parameter Class Descriptor bit values . 97
Table 125 – Parameter object instance attributes. 98
Table 126 – Semantics of Descriptor Instance attribute . 99
Table 127 – Descriptor Scaling bits usage . 99
Table 128 – Minimum and Maximum Value semantics .
...