IEC 61158-6-26:2023

IEC 61158-6-26 ®
Edition 2.0 2023-03
INTERNATIONAL
STANDARD
Industrial communication networks – Fieldbus specifications –
Part 6-26: Application layer protocol specification – Type 26 elements

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IEC 61158-6-26 ®
Edition 2.0 2023-03
INTERNATIONAL
STANDARD
Industrial communication networks – Fieldbus specifications –

Part 6-26: Application layer protocol specification – Type 26 elements

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 25.040.40; 35.100.70; 35.110 ISBN 978-2-8322-6630-4

– 2 – IEC 61158-6-26:2023 © IEC 2023
CONTENTS
FOREWORD . 11
INTRODUCTION . 13
1 Scope . 14
1.1 General . 14
1.2 Specifications . 15
1.3 Conformance . 15
2 Normative references . 15
3 Terms, definitions, symbols, abbreviated terms and conventions . 16
3.1 Terms and definitions from other ISO/IEC standards . 17
3.1.1 Terms and definitions from ISO/IEC 7498-1 . 17
3.1.2 Terms and definitions from ISO/IEC 8822 . 17
3.1.3 Terms and definitions from ISO/IEC 9545 . 17
3.1.4 Terms and definitions from ISO/IEC 8824-1 . 17
3.1.5 Terms and definitions from ISO/IEC 8825-1 . 18
3.2 Type 26 specific terms and definitions . 18
3.3 Abbreviated terms and symbols . 22
3.4 Conventions . 24
3.4.1 Conventions used in state machines . 24
3.4.2 Convention for abstract syntax description . 26
3.4.3 Convention for reserved bits and octets . 26
3.4.4 Conventions for bit description in octets . 26
4 FAL syntax description . 27
4.1 General . 27
4.2 Overview of Type 26 fieldbus . 27
4.2.1 Application field and Common-memory . 27
4.2.2 Structure of Type 26 protocol . 28
4.2.3 Structure of Type 26 FAL . 29
4.2.4 Data link layer . 30
4.3 Operating principle . 31
4.3.1 Overview . 31
4.3.2 Logical ring maintenance . 31
4.3.3 Node addition . 34
4.3.4 Node in a logical ring . 38
4.3.5 Node drop-out . 39
4.3.6 Data transmission . 39
4.3.7 Data transmission frames . 49
4.4 FAL PDU abstract syntax . 52
4.4.1 Basic abstract syntax . 52
4.4.2 Transparent-msg- PDU . 55
4.4.3 Token-PDU . 55
4.4.4 Participation-req-PDU . 56
4.4.5 Byte-block-read PDUs . 56
4.4.6 Byte-block-write PDUs . 56
4.4.7 Word-block-read PDUs . 56
4.4.8 Word-block-write PDUs . 57
4.4.9 Network-parameter-read PDUs . 57
4.4.10 Network-parameter-write PDUs. 57

4.4.11 Stop-command PDUs . 57
4.4.12 Operation-command PDUs . 58
4.4.13 Profile-read PDUs . 58
4.4.14 Trigger-PDU . 58
4.4.15 Log-data-read PDUs . 58
4.4.16 Log-data-clear PDUs . 59
4.4.17 Message-return PDUs . 59
4.4.18 Vendor-specific-msg PDUs . 59
4.4.19 Start-TK-hld-time-mrmt PDUs . 60
4.4.20 Terminate-TK-hld-time-mrmt PDUs . 60
4.4.21 Start-GP_Comm-sndr-log PDUs . 60
4.4.22 Terminate-GP_Comm-sndr-log PDUs . 60
4.4.23 Set-remote-node-config-para PDUs . 61
4.4.24 Read-rmt-partici-node-mgt-info-para PDUs . 61
4.4.25 Read-rmt- node-mgt-info-para PDUs . 61
4.4.26 Read-rmt-node-set-info-para PDUs . 61
4.4.27 Reset-node PDUs . 62
4.4.28 Cyclic-data PDUs . 62
4.4.29 Extended-prticiption-req-PDU . 62
4.4.30 Extended-network-parameter-read PDUs . 63
4.4.31 Extended-network-parameter-write PDUs . 63
4.5 Data type assignments . 63
5 Transfer syntax . 65
5.1 Encoding rules . 65
5.1.1 Basic encoding . 65
5.1.2 Fixed length Unsigned encoding . 65
5.1.3 Fixed length BitString encoding . 65
5.1.4 OctetString encoding . 65
5.1.5 SEQUENCE encoding . 65
5.2 PDU elements encoding . 65
5.2.1 FALARHeader . 65
5.2.2 Transparent-msg PDU . 69
5.2.3 Token-PDU . 70
5.2.4 Participation-req-PDU . 71
5.2.5 Byte-block-read PDUs . 72
5.2.6 Byte-block-write PDUs . 74
5.2.7 Word-block-read PDUs . 75
5.2.8 Word-block-write PDUs . 77
5.2.9 Network-parameter-read PDUs . 79
5.2.10 Network-parameter-write PDUs. 83
5.2.11 Stop-command PDUs . 85
5.2.12 Operation-command PDUs . 87
5.2.13 Profile-read PDUs . 89
5.2.14 Trigger-PDU . 92
5.2.15 Log-data-read PDUs . 92
5.2.16 Log-data-clear PDUs . 98
5.2.17 Message-return PDUs . 100
5.2.18 Vendor-specific-msg PDUs . 102
5.2.19 Start-TK-hld-time-mrmt PDUs . 105

– 4 – IEC 61158-6-26:2023 © IEC 2023
5.2.20 Terminate-TK-hld-time-mrmt PDUs . 106
5.2.21 Start-GP_Comm-sndr-log PDUs . 110
5.2.22 Terminate-GP_Comm-sndr-log PDUs . 111
5.2.23 Set-remote-node-config-para PDUs . 114
5.2.24 Read-rmt-partici-node-mgt-info-para PDUs . 117
5.2.25 Read-rmt- node-mgt-info-para PDUs . 120
5.2.26 Read-rmt-node-set-info-para PDUs . 123
5.2.27 Reset-node PDUs . 125
5.2.28 Cyclic-data PDUs . 126
5.2.29 Extended-participation-request PDU . 129
5.2.30 Extended-network-parameter-read PDUs . 129
5.2.31 Extended-network-parameter-write PDUs . 132
6 FAL protocol state machines structure . 135
6.1 Overview. 135
6.2 Common variables, parameters, timers, counters, lists and queues . 136
6.2.1 V(3CWT), P(3CWT), T(3CWT): Three-lap-time-period-of-the-token-
circulation . 136
6.2.2 V(ACK): ACK received . 136
6.2.3 V(ACK_TN): ACK to this node . 137
6.2.4 V(AWT), P(AWT), T(AWT): Waiting-time-period-for-receiving-message-
acknowledge. 137
6.2.5 V(CBN): Current fragment number for fragmented cyclic-data
transmission . 137
6.2.6 V(CTFG): Cyclic-data fragment transfer . 137
6.2.7 V(CTRen), P (CTRen): Cyclic-data on CM1 and CM2 receive enable . 137
6.2.8 V(CTRQ): Cyclic-data transfer request . 137
6.2.9 V(ExCTRQ): Cyclic-data of CM3 transfer request . 138
6.2.10 C(ExCT): Cumulative count of extended-cyclic-data transmission . 138
6.2.11 V(ExCTRen), P(ExCTRen): Cyclic-data on CM3 receive enable . 138
6.2.12 V(ExTBN), P(ExTBN): Total fragment number of Cyclic-data on CM3 . 138
6.2.13 V(ExTSZ), P(ExTSZ): Total cyclic-data size on CM3 . 138
6.2.14 C(MCNT): Cumulative count of message transmission carried over . 138
6.2.15 V(MCV): Message transmission carried over. 138
6.2.16 V(MFT), P(MFT), T(MFT): Allowable-minimum-frame-interval-time. 138
6.2.17 V(MmtCntType): Measurement control type . 139
6.2.18 V(MRVRQ): Message receive request . 139
6.2.19 V(MSRQ): Message transfer request . 139
6.2.20 Q(MSRXQ): Message-RX-Queue . 139
6.2.21 Q(MTXQ): Message-TX-Queue . 139
6.2.22 V(NMTP): No message transmission in previous cycle . 139
6.2.23 V(PAT), P(PAT), T(PAT): Participation-request-frame-acceptance-time . 140
6.2.24 V(PnMgtIF): Participation-node-management-information List . 140
6.2.25 V(PWT), T(PWT): Participation-request-frame-transmission-waiting-time . 140
6.2.26 V(RCT): Allowable-refresh-cycle-time . 140
6.2.27 V(RMT), T(RMT): Refresh-cycle-measurement-time. 140
6.2.28 C(RTX): Retransmission count . 141
6.2.29 V(SEQ): Sequence number value List . 141
6.2.30 V(SN): Successor node . 141
6.2.31 V(SrtMmt): Measurement started . 141

6.2.32 Q(SVRXQ): Server-RX Queue . 141
6.2.33 Q(SVTXQ): Server-TX Queue . 141
6.2.34 V(TBN), P(TBN): Total fragment number of Cyclic-data on CM1 and
CM2 . 141
6.2.35 V(TDT), P(TDT), T(TDT): Joining-token-detection-time . 141
6.2.36 V(THT), P(THT), T(THT): Token-holding-time . 142
6.2.37 V(TK): Token holding . 142
6.2.38 V(TKH): Token holding node . 142
6.2.39 V(TN): Node identifier number . 142
6.2.40 V(TrWT), T(TrWT): Trigger-frame-transmission-waiting-time . 142
6.2.41 V(TSZ), P(TSZ): Total cyclic-data size on CM1 and CM2 . 142
6.2.42 V(TW), P(TW ), T(TW)( ): Token-watchdog-time . 142
6.2.43 V(VSEQ): Version of sequence number value List . 142
6.3 Functions used in state tables . 143
7 FAL service protocol machine (FSPM) . 146
7.1 Overview. 146
7.2 Cyclic-data protocol machine . 146
7.2.1 Overview . 146
7.2.2 Cyclic-data primitives between FAL user and FSPM . 146
7.2.3 State table . 147
7.3 Message data protocol machine . 149
7.3.1 Overview . 149
7.3.2 Message-data primitive between FAL user and FSPM . 149
7.3.3 State table . 153
7.4 Load measurement protocol machine . 163
7.4.1 Overview . 163
7.4.2 Load measurement primitives between FAL user and FSPM . 163
7.4.3 State table . 164
7.5 General purpose communication server protocol machine . 168
7.5.1 Overview . 168
7.5.2 GP command server primitives between FAL user and FSPM . 168
7.5.3 State table . 168
7.6 Network management protocol machine . 170
7.6.1 Overview . 170
7.6.2 Network management primitives . 170
7.6.3 State table . 171
8 Application relationship protocol machine (ARPM) . 174
8.1 Overview. 174
8.2 Cyclic-TX/RX control . 175
8.2.1 Overview . 175
8.2.2 Cyclic-TX/RX control primitives between FSPM and ARPM . 175
8.2.3 State table . 176
8.3 Message-TX/RX control . 176
8.3.1 Overview . 176
8.3.2 Message-TX/RX control primitives between FSPM and ARPM . 176
8.3.3 State table . 177
8.4 Command server TX/RX control . 177
8.4.1 Overview . 177
8.4.2 Command server TX/RX primitives between FSPM and ARPM . 178

– 6 – IEC 61158-6-26:2023 © IEC 2023
8.4.3 State table . 178
8.5 AR control . 178
8.5.1 Overview . 178
8.5.2 AR control primitives between FSPM and ARPM . 179
8.5.3 State table . 179
9 DLL mapping protocol machine (DMPM) . 202
9.1 Overview. 202
9.2 Mapping of DMPM service primitives and DLL service primitives . 202
9.3 Mapping DMPM service port to DLSAP . 204
9.4 Mapping of Network address to each node . 204
Bibliography . 206

Figure 1 – Bit identification in an octet . 26
Figure 2 – Bit identification in multiple octets (four-octet case) . 27
Figure 3 – Data sharing with the CM . 28
Figure 4 – Protocol stack for Type 26 fieldbus . 29
Figure 5 – The structure of ASEs for Type 26 FAL . 30
Figure 6 – A token circulation on a logical ring . 32
Figure 7 – Logical ring recovery . 34
Figure 8 – An example in case of start simultaneously with another node . 36
Figure 9 – Start alone case . 37
Figure 10 – Node addition: in-ring start-up state . 38
Figure 11 – Data sharing with the CM . 40
Figure 12 – Configuration of the Common-memory . 41
Figure 13 – Example of train of multiple extended-cyclic-data frames . 42
Figure 14 – APDUs of cyclic-data frames containing fragmented data . 43
Figure 15 – Example of sequential diagram of ACK over UDP channel . 46
Figure 16 – Delivery confirmation checked by TCP protocol . 47
Figure 17 – Train of data frames and a token frame . 49
Figure 18 – Frame structure . 50
Figure 19 – Structure of Trans-msgData . 70
Figure 20 – Structure of B_Blk_Rd_rspData with M_RLT = 0 . 73
Figure 21 – Structure of B_Blk_Rd_rspData in case of M_RLT = 1 . 73
Figure 22 – Structure of B_Blk_Wt_reqDat . 75
Figure 23 – Structure of B_Blk_Wt_rspData in case of M_RLT = 1 . 75
Figure 24 – Structure of W_Blk_Rd_rspData with M_RLT = 0 . 77
Figure 25 – Structure of W_Blk_Rd_rspData in case of M_RLT = 1 . 77
Figure 26 – Structure of W_Blk_Wt_reqDat . 79
Figure 27 – Structure of W_Blk_Wt_rspData in case of M_RLT = 1 . 79
Figure 28 – Structure of Net-para-Rd-rspData with M_RLT = 0 . 81
Figure 29 – Structure of Net-para-Rd-rspData with M_RLT = 1 . 82
Figure 30 – Structure of Net-para-Wrt-reqData. 84
Figure 31 – Structure of Net-para-Wrt-rspData with M_RLT = 1 . 85
Figure 32 – Structure of Stop-cmdData with M_RLT = 1 . 87

Figure 33 – Structure of Op-cmdData with M_RLT = 1 . 88
Figure 34 – Structure of Profile-readData with M_RLT = 0 . 90
Figure 35 – Structure of Profile-readData with M_RLT = 1 . 92
Figure 36 – Structure of Log-readData with M_RLT = 0 . 94
Figure 37 – Structure of Log-readData with M_RLT = 1 . 98
Figure 38 – Structure of Log-clearData . 99
Figure 39 – Structure of Msg-return-reqData . 101
Figure 40 – Structure of Msg-return-rspData . 102
Figure 41 – Structure of V_msg_reqData . 104
Figure 42 – Structure of V_msg_rspData in case of M_RLT = 0 . 104
Figure 43 – Structure of V_msg_rspData in case of M_RLT = 1 . 105
Figure 44 – Token-holding-time measurement result . 109
Figure 45 – Structure of Sndr-logData . 114
Figure 46 – Structure of Set-remote-node-config-para-ReqData . 116
Figure 47 – Structure of Set-remote-node-config-para-RspData . 117
Figure 48 – Structure of Read-rmt-partici-node-mgt-info-ReqData . 119
Figure 49 – Structure of Read-rmt-partici-node-mgt-info-RspData . 119
Figure 50 – Structure of Rmt-node-mgt-info-paraData . 122
Figure 51 – Structure of Set-info-para-read-data . 124
Figure 52 – Structure of ACKdata . 128
Figure 53 – Structure of Ex-Net-para-Rd-rspData with M_RLT = 0 . 131
Figure 54 – Structure of Ex-Net-para-Rd-rspData with M_RLT = 1 . 132
Figure 55 – Structure of Ex-Net-para-Wrt-reqData . 134
Figure 56 – Structure of Ex-Net-para-Wrt-rspData with M_RLT = 1 . 135
Figure 57 – Relationship between FAL protocol machines . 136
Figure 58 – Overall structure of FSPM . 146
Figure 59 – State transition diagram of Cyclic-data protocol machine. 147
Figure 60 – State transition diagram of Message-data protocol machine . 154
Figure 61 – State transition diagram of Load measurement protocol machine . 164
Figure 62 – State transition diagram of GP-command-server protocol machine . 169
Figure 63 – State transition diagram of Network management protocol machine . 172
Figure 64 – Overall structure of ARPM . 175
Figure 65 – State transition diagram of Cyclic-TX/RX control . 176
Figure 66 – State transition diagram of Message-TX/RX control . 177
Figure 67 – State transition diagram of Command server TX/RX protocol machine . 178
Figure 68 – Overall state transition diagram of AR control protocol machine . 180
Figure 69 – State transition diagram for message-data transmission . 196
Figure 70 – State transition diagram for ACK creation and message-data reception . 199
Figure 71 – Overall structure of DMPM . 202
Figure 72 – DLSAP mapping . 204
Figure 73 – Structure of IP address . 205

Table 1 – Conventions used for state machines . 25

– 8 – IEC 61158-6-26:2023 © IEC 2023
Table 2 – Conventions used in state machine . 25
Table 3 – Available functions to message-data transfer on UDP channel . 44
Table 4 – Data transmission frame and the TCD value . 50
Table 5 – Upper layer operating condition matrix . 67
Table 6 – Transparent-msg-PDU specific values . 70
Table 7 – Token-PDU specific values . 71
Table 8 – Participation-req -PDU specific values . 71
Table 9 – Byte-block-read-req-PDU specific values . 72
Table 10 – Byte-block-read-rsp-PDU specific values . 72
Table 11 – Byte-block-write-req-PDU specific values . 74
Table 12 – Byte-block-write-rsp-PDU specific values . 74
Table 13 – Word-block-read-req-PDU specific values . 76
Table 14 – Word-block-read-rsp-PDU specific values . 76
Table 15 – Word-block-write-req-PDU specific values . 78
Table 16 – Word-block-write-rsp-PDU specific values . 78
Table 17 – Network-parameter-read-req-PDU specific values . 80
Table 18 – Network-parameter-read-rsp-PDU specific values . 80
Table 19 – Values of data elements of Net-para-Rd-rspData . 82
Table 20 – Network-parameter-write-req-PDU specific values . 83
Table 21 – Network-parameter-write-rsp-PDU specific values . 83
Table 22 – Values of the data elements of Net-para-Wrt-reqData . 84
Table 23 – Stop-command-req-PDU specific values . 85
Table 24 – Stop-command-rsp-PDU specific values . 86
Table 25 – Operation-command-req-PDU specific values . 87
Table 26 – Operation-command-rsp-PDU specific values . 88
Table 27 – Profile-read-req-PDU specific values . 89
Table 28 – Profile-read-rsp-PDU specific values . 90
Table 29 – Trigger-PDU specific values . 92
Table 30 – Log-data-read-req-PDU U specific values . 93
Table 31 – Log-data-read-rsp-PDU specific values . 93
Table 32 – Contents of Log-readData . 94
Table 33 – Log-data-clear-req-PDU specific values . 98
Table 34 – Log-data-clear-rsp-PDU specific values . 99
Table 35 – Message-return-req-PDU specific values . 100
Table 36 – Message-return-rsp-PDU specific values . 100
Table 37 – Vendor-specific-msg-req-PDU specific values . 102
Table 38 – Vendor-specific-msg-rsp-PDU specific values . 103
Table 39 – Start-TK-hld-time-mrmt-req-PDU specific values . 105
Table 40 – Start-TK-hld-time-mrmt-rsp-PDU specific values . 106
Table 41 – Terminate-TK-hld-time-mrmt-req-PDU specific values . 107
Table 42 – Terminate-TK-hld-time-mrmt-rsp-PDU specific values . 108
Table 43 – Value of the data element of TK-hld-timeData . 109
Table 44 – Start-GP_Comm-sndr-log-req-PDU specific values . 110

Table 45 – Start-GP_Comm-sndr-log-rsp-PDU specific values . 111
Table 46 – Terminate-GP_Comm-sndr-log-req-PDU specific values . 112
Table 47 – Terminate-GP_Comm-sndr-log-req-PDU specific values . 113
Table 48 – Value of the data element of Sndr-logData . 114
Table 49 – Set-remote-node-config-para-req-PDU specific values . 115
Table 50 – Set-remote-node-config-para-rsp-PDU specific values . 115
Table 51 – Value of the data element of Set-remote-node-config-para-ReqData . 116
Table 52 – Bit definition of Update flag . 117
Table 53 – Value of the data element of Set-remote-node-config-para-RspData . 117
Table 54 – Read-rmt-partici-node-mgt-info-para-req-PDU specific values . 118
Table 55 – Read-rmt-partici-node-mgt-info-para-rsp-PDU specific values . 118
Table 56 – Value of the data element of Read-rmt-partici-node-mgt-info-RspData . 120
Table 57 – Read-rmt- node-mgt-info-para-req-PDU specific values . 120
Table 58 – Read-rmt- node-mgt-info-para-rsp-PDU specific values . 121
Table 59 – Value of the data element of Rmt-node-mgt-info-paraData . 122
Table 60 – Bit definition of Node status . 123
Table 61 – Read-rmt-node-set-info-para-req-PDU specific values . 123
Table 62 – Read-rmt-node-set-info-para-rsp-PDU specific values . 124
Table 63 – Value of the data element of Set-info-para-read-data . 125
Table 64 – Rest-node-req-PDU specific values . 125
Table 65 – Rest-node-rsp-PDU specific values . 126
Table 66 – Cyclic-data-w/wo-ACK-PDU specific values . 126
Table 67 – Extended-cyclic-data-PDU specific values . 127
Table 68 – Value of the element of ACKdata . 128
Table 69 – Value of R_STSx field . 128
Table 70 – Extended-participation-req-PDU specific values . 129
Table 71 – Extended-network-parameter-read-req-PDU specific values . 130
Table 72 – Extended-network-parameter-read-rsp-PDU specific values . 131
Table 73 – Values of data elements of Ex-Net-para-Rd-rspData . 131
Table 74 – Ex-network-parameter-write-req-PDU specific values . 133
Table 75 – Ex-network-parameter-write-rsp-PDU specific values . 134
Table 76 – Values of data elements of Ex-Net-para-Wrt-reqData . 135
Table 77 – Value of R_STSx field . 137
Table 78 – Functions used in state tables . 143
Table 79 – Cyclic-data primitives between FAL user and FSPM . 147
Table 80 – State table of Cyclic-data protocol machine . 148
Table 81 – Message-data primitives between FAL user and FSPM . 150
Table 82 – State table of Message-data protocol machine . 154
Table 83 – Load measurement primitives between FAL user and FSPM . 163
Table 84 – State table of Load measurement protocol machine. 164
Table 85 – GP command server primitives between FAL user and FSPM . 168
Table 86 – State table of General purpose command server protocol machine . 169
Table 87 – Primitives used in network managem
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