EN 60870-5-101:2003

SLOVENSKI STANDARD
01-maj-2004
1DGRPHãþD
SIST EN 60870-5-101:1997
SIST EN 60870-5-101:1997/A1:2002
SIST EN 60870-5-101:1997/A2:2002
Oprema in sistemi za daljinsko vodenje - 6-101. del: Protokoli prenosa -
Spremljevalni standardi za osnovne naloge daljinskega vodenja (IEC 60870-5-
101:2003)
Telecontrol equipment and systems -- Part 5-101: Transmission protocols - Companion
standard for basic telecontrol tasks
Fernwirkeinrichtungen und -systeme -- Teil 5-101: Übertragungsprotokolle -
Anwendungsbezogene Norm für grundlegende Fernwirkaufgaben
Matériel et systèmes de téléconduite -- Partie 5-101: Protocoles de transmission - Norme
d'accompagnement pour les tâches élémentaires de téléconduite
Ta slovenski standard je istoveten z: EN 60870-5-101:2003
ICS:
33.200 Daljinsko krmiljenje, daljinske Telecontrol. Telemetering
meritve (telemetrija)
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD EN 60870-5-101
NORME EUROPÉENNE
EUROPÄISCHE NORM April 2003
ICS 33.200 Supersedes EN 60870-5-101:1996 + A1:2000 + A2:2001

English version
Telecontrol equipment and systems
Part 5-101: Transmission protocols –
Companion standard for basic telecontrol tasks
(IEC 60870-5-101:2003)
Matériel et systèmes de téléconduite Fernwirkeinrichtungen und -systeme
Partie 5-101: Protocoles de transmission - Teil 5-101: Übertragungsprotokolle -
Norme d'accompagnement Anwendungsbezogene Norm
pour les tâches élémentaires für grundlegende Fernwirkaufgaben
de téléconduite (IEC 60870-5-101:2003)
(CEI 60870-5-101:2003)
This European Standard was approved by CENELEC on 2003-04-01. CENELEC members are bound to
comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European
Standard the status of a national standard without any alteration.

Up-to-date lists and bibliographical references concerning such national standards may be obtained on
application to the Central Secretariat or to any CENELEC member.

This European Standard exists in three official versions (English, French, German). A version in any other
language made by translation under the responsibility of a CENELEC member into its own language and
notified to the Central Secretariat has the same status as the official versions.

CENELEC members are the national electrotechnical committees of Austria, Belgium, Czech Republic,
Denmark, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Luxembourg, Malta,
Netherlands, Norway, Portugal, Slovakia, Spain, Sweden, Switzerland and United Kingdom.

CENELEC
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung

Central Secretariat: rue de Stassart 35, B - 1050 Brussels

© 2003 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.

Ref. No. EN 60870-5-101:2003 E

Foreword
The text of document 57/605/FDIS, future edition 2 of IEC 60870-5-101, prepared by IEC TC 57,
Power system control and associated communications, was submitted to the IEC-CENELEC parallel
vote and was approved by CENELEC as EN 60870-5-101 on 2003-04-01.
This European Standard supersedes EN 60870-5-101:1996 + A1:2000 + A2:2001.
The following dates were fixed:
– latest date by which the EN has to be implemented
at national level by publication of an identical
national standard or by endorsement (dop) 2004-01-01
– latest date by which the national standards conflicting
with the EN have to be withdrawn (dow) 2006-04-01

Annexes designated "normative" are part of the body of the standard.
Annexes designated "informative" are given for information only.
In this standard, annex ZA is normative and annexes A and B are informative.
Annex ZA has been added by CENELEC.
__________
Endorsement notice
The text of the International Standard IEC 60870-5-101:2003 was approved by CENELEC as a
European Standard without any modification.
__________
- 3 - EN 60870-5-101:2003
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications
This European Standard incorporates by dated or undated reference, provisions from other
publications. These normative references are cited at the appropriate places in the text and the
publications are listed hereafter. For dated references, subsequent amendments to or revisions of any
of these publications apply to this European Standard only when incorporated in it by amendment or
revision. For undated references the latest edition of the publication referred to applies (including
amendments).
NOTE When an international publication has been modified by common modifications, indicated by (mod), the relevant
EN/HD applies.
Publication Year Title EN/HD Year
IEC 60050-371 1984 International Electrotechnical - -
Vocabulary - Chapter 371: Telecontrol

IEC 60870-1-1 1988 Telecontrol equipment and systems - -
Part 1: General considerations –
Section 1: General principles
IEC 60870-5-1 1990 Part 5: Transmission protocols – EN 60870-5-1 1993
Section 1: Transmission frame formats

IEC 60870-5-2 1992 Part 5: Transmission protocols – EN 60870-5-2 1993
Section 2: Link transmission procedures

IEC 60870-5-3 1992 Part 5: Transmission protocols – EN 60870-5-3 1992
Section 3: General structure of
application data
IEC 60870-5-4 1993 Part 5: Transmission protocols – EN 60870-5-4 1993
Section 4: Definition and coding of
application information elements

IEC 60870-5-5 1995 Part 5: Transmission protocols – EN 60870-5-5 1995
Section 5: Basic application functions

IEC 60870-5-103 1997 Part 5-103: Transmission protocols - EN 60870-5-103 1998
Companion standard for the informative
interface of protection equipment

ISO/IEC 8824-1 2000 Information technology - Abstract - -
Syntax Notation One (ASN.1):
Specification of basic notation

ITU-T V.24 2000 List of definitions for interchange circuits - -
between data terminal equipment (DTE)
and data circuit-terminating equipment
(DCE)
ITU-T V.28 1993 Electrical characteristics for unbalanced - -
double-current interchange circuits

Publication Year Title EN/HD Year
ITU-T X.24 1988 List of definitions for interchange circuits - -
between Data Terminal Equipment
(DTE) and Data Circuit-terminating
Equipment (DCE) on public data
networks
ITU-T X.27/V.11 1996 Electrical characteristics for balanced - -
double-current interchange circuits
operating at data signalling rates up to
10 Mbit/s
IEEE 754 1985 Standard for Binary Floating-Point - -
Arithmetic
INTERNATIONAL IEC
STANDARD
60870-5-101
Second edition
2003-02
Telecontrol equipment and systems –
Part 5-101:
Transmission protocols –
Companion standard for basic telecontrol tasks
Matériels et systèmes de téléconduite –
Partie 5-101:
Protocoles de transmission –
Norme d'accompagnement pour les tâches élémentaires
de téléconduite
 IEC 2003  Copyright - all rights reserved
No part of this publication may be reproduced or utilized in any form or by any means, electronic or
mechanical, including photocopying and microfilm, without permission in writing from the publisher.
International Electrotechnical Commission, 3, rue de Varembé, PO Box 131, CH-1211 Geneva 20, Switzerland
Telephone: +41 22 919 02 11 Telefax: +41 22 919 03 00 E-mail: inmail@iec.ch  Web: www.iec.ch
PRICE CODE
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XH
International Electrotechnical Commission
Международная Электротехническая Комиссия
For price, see current catalogue

– 2 – 60870-5-101  IEC:2003(E)
CONTENTS
FOREWORD . 7
1 Scope and object . 8
2 Normative references. 8
3 Terms and definitions. 9
4 General rules .10
4.1 Protocol structure.10
4.2 Physical layer.11
4.3 Link layer .12
4.4 Application layer .12
4.5 User process .12
5 Physical layer.12
5.1 Selections from ISO and ITU-T standards .12
5.1.1 ITU-T V.24 or ITU-T V.28 unbalanced interchange circuit .13
5.1.2 ITU-T X.24 or ITU-T X.27 balanced interchange circuit .14
5.1.3 Interfaces to switched communication networks.14
5.1.4 Other compatible interfaces.14
6 Link layer .14
6.1 Selections from IEC 60870-5-1: Transmission frame formats.14
6.2 Selections from IEC 60870-5-2: Link transmission procedures.15
6.2.1 State transition diagrams.15
6.2.2 Definitions of time out interval for repeated frame transmission .24
6.2.3 The use of the different resets.26
7 Application layer and user process .27
7.1 Selections from IEC 60870-5-3: General structure of application data.27
7.2 Selections from IEC 60870-5-4: Definition and coding of application
information elements.29
7.2.1 Type identification .29
7.2.2 Variable structure qualifier.33
7.2.3 Cause of transmission.36
7.2.4 COMMON ADDRESS OF ASDUs .41
7.2.5 INFORMATION OBJECT ADDRESS.42
7.2.6 INFORMATION ELEMENTS.44
7.3 Definition and presentation of the specific ASDUs .58
7.3.1 ASDUs for process information in monitor direction .59
7.3.2 ASDUs for process information in control direction .98
7.3.3 ASDUs for system information in monitor direction .103
7.3.4 ASDUs for system information in control direction.104
7.3.5 ASDUs for parameter in control direction.109
7.3.6 ASDUs for file transfer .113
7.4 Selections from IEC 60870-5-5: Basic application functions .120
7.4.1 Selections from station initialization.121
7.4.2 Selections from data acquisition by polling.121
7.4.3 Selections from cyclic data transmission.121
7.4.4 Selections from acquisition of events.121
7.4.5 Selections from station interrogation, outstation interrogation .121
7.4.6 Selections from clock synchronization .125

60870-5-101  IEC:2003(E) − 3 −
7.4.7 Selections from command transmission.125
7.4.8 Selections from transmission of integrated totals .125
7.4.9 Selections from parameter loading .129
7.4.10 Selections from test procedure .129
7.4.11 Selections from file transfer.129
7.4.12 Selections from acquisition of transmission delay .148
7.4.13 Background scan .148
7.4.14 Read procedure .148
8 Interoperability .149
8.1 System or device .150
8.2 Network configuration .150
8.3 Physical layer.150
8.4 Link layer .151
8.5 Application layer .151
8.6 Basic application functions .157
Annex A (informative) Proof of the synchronization stability of
frame format class FT 1.2.161
Annex B (informative) Admittance of line idle intervals between characters of
frame format class FT 1.2.177
Figure 1 – Selected standard provisions of the defined telecontrol companion standard .11
Figure 2 – Interfaces and connections of controlling and controlled stations .11
Figure 3 – State transition diagram by Grady Booch/Harel.15
Figure 4 – Unbalanced transmission procedures, primary and secondary stations .17
Figure 5 – State transition diagram for unbalanced transmission primary to secondary .18
Figure 6 – State transition diagram for unbalanced transmission secondary to primary .19
Figure 7 – Balanced transmission procedures, primary and secondary link layers.21
Figure 8 – State transition diagram for balanced transmission primary to secondary.22
Figure 9 – State transition diagram for balanced transmission secondary to primary.23
Figure 10 – Structure of an Application Service Data Unit ASDU .28
Figure 11 – Type identification.29
Figure 12 – VARIABLE STRUCTURE QUALIFIER.33
Figure 13 – Presentation of types of information objects in priority buffers.35
Figure 14 – CAUSE OF TRANSMISSION field.36
Figure 15 – Station interrogation via a concentrator station using the originator address.38
Figure 16 – Command transmission via a concentrator station using the originator address .39
Figure 17 – COMMON ADDRESS of ASDUs (one octet) .41
Figure 18 – COMMON ADDRESS of ASDUs (two octets).41
Figure 19 – INFORMATION OBJECT ADDRESS (one octet) .42
Figure 20 – INFORMATION OBJECT ADDRESS (two octets).42
Figure 21 – INFORMATION OBJECT ADDRESS (three octets) .43
Figure 22 – ASDU: M_SP_NA_1 Single-point information without time tag.59
Figure 23 – ASDU: M_SP_NA_1 Sequence of single-point information without time tag.60
Figure 24 – ASDU: M_SP_TA_1 Single-point information with time tag.61
Figure 25 – ASDU: M_DP_NA_1 Double-point information without time tag .62

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Figure 26 – ASDU: M_DP_NA_1 Sequence of double-point information without time tag .62
Figure 27 – ASDU: M_DP_TA_1 Double-point information with time tag .63
Figure 28 – ASDU: M_ST_NA_1 Step position information .64
Figure 29 – ASDU: M_ST_NA_1 Sequence of step position information .64
Figure 30 – ASDU: M_ST_TA_1 Step position information with time tag .65
Figure 31 – ASDU: M_BO_NA_1 Bitstring of 32 bit.66
Figure 32 – ASDU: M_BO_NA_1 Sequence of bitstrings of 32 bit .67
Figure 33 – ASDU: M_BO_TA_1 Bitstring of 32 bit .68
Figure 34 – ASDU: M_ME_NA_1 Measured value, normalized value .69
Figure 35 – ASDU: M_ME_NA_1 Sequence of measured values, normalized values.69
Figure 36 – ASDU: M_ME_TA_1 Measured value, normalized value with time tag .70
Figure 37 – ASDU: M_ME_NB_1 Measured value, scaled value .71
Figure 38 – ASDU: M_ME_NB_1 Sequence of measured values, scaled values .72
Figure 39 – ASDU: M_ME_TB_1 Measured value, scaled value with time tag .73
Figure 40 – ASDU: M_ME_NC_1 Measured value, short floating point number .74
Figure 41 – ASDU: M_ME_NC_1 Sequence of measured values, short floating
point number.75
Figure 42 – ASDU: M_ME_TC_1 Measured value, short floating point number
with time tag.76
Figure 43 – ASDU: M_IT_NA_1 Integrated totals.77
Figure 44 – ASDU: M_IT_NA_1 Sequence of integrated totals.78
Figure 45 – ASDU: M_IT_TA_1 Integrated totals with time tag .79
Figure 46 – ASDU: M_EP_TA_1 Event of protection equipment with time tag .80
Figure 47 – ASDU: M_EP_TB_1 Packed start events of protection equipment
with time tag.81
Figure 48 – ASDU: M_EP_TC_1 Packed output circuit information of protection
equipment with time tag.82
Figure 49 – ASDU: M_PS_NA_1 Packed single-point information with status
change detection .83
Figure 50 – ASDU: M_PS_NA_1 Sequence of packed single-point information with status
change detection .84
Figure 51 – ASDU: M_ME_ND_1 Measured value, normalized value without quality
descriptor .85
Figure 52 – ASDU: M_ME_ND_1 Sequence of measured values, normalized values
without quality descriptor .85
Figure 53 – ASDU: M_SP_TB_1 Single-point information with time tag CP56Time2a.86
Figure 54 – ASDU: M_DP_TB_1 Double-point information with time tag CP56Time2a .87
Figure 55 – ASDU: M_ST_TB_1 Step position information with time tag CP56Time2a .88
Figure 56 – ASDU: M_BO_TB_1 Bitstring of 32 bits with time tag CP56Time2a .89
Figure 57 – ASDU: M_ME_TD_1 Measured value, normalized value with time tag
CP56Time2a .90
Figure 58 – ASDU: M_ME_TE_1 Measured value, scaled value with time tag
CP56Time2a .91
Figure 59 – ASDU: M_ME_TF_1 Measured value, short floating point number with
time tag CP56Time2a .93
Figure 60 – ASDU: M_IT_TB_1 Integrated totals with time tag CP56Time2a.94
Figure 61 – ASDU: M_EP_TD_1 Event of protection equipment with time tag CP56Time2a .95

60870-5-101  IEC:2003(E) − 5 −
Figure 62 – ASDU: M_EP_TE_1 Packed start events of protection equipment with
time tag CP56Time2a .96
Figure 63 – ASDU: M_EP_TF_1 Packed output circuit information of protection equipment
with time tag CP56Time2a.97
Figure 64 – ASDU: C_SC_NA_1 Single command.98
Figure 65 – ASDU: C_DC_NA_1 Double command .98
Figure 66 – ASDU: C_RC_NA_1 Regulating step command .99
Figure 67 – ASDU: C_SE_NA_1 Set-point command, normalized value.100
Figure 68 – ASDU: C_SE_NB_1 Set-point command, scaled value.100
Figure 69 – ASDU: C_SE_NC_1 Set-point command, short floating point number .101
Figure 70 – ASDU: C_BO_NA_1 Bitstring of 32 bit .102
Figure 71 – ASDU: M_EI_NA_1 End of initialization .103
Figure 72 – ASDU: C_IC_NA_1 Interrogation command .104
Figure 73 – ASDU: C_CI_NA_1 Counter interrogation command .104
Figure 74 – ASDU: C_RD_NA_1 Read command.105
Figure 75 – ASDU: C_CS_NA_1 Clock synchronization command.106
Figure 76 – ASDU: C_TS_NA_1 Test command.107
Figure 77 – ASDU: C_RP_NA_1 Reset process command .107
Figure 78 – ASDU: C_CD_NA_1 Delay acquisition command .108
Figure 79 – ASDU: P_ME_NA_1 Parameter of measured values, normalized value .109
Figure 80 – ASDU: P_ME_NB_1 Parameter of measured values, scaled value.110
Figure 81 – ASDU: P_ME_NC_1 Parameter of measured values, short floating
point number .111
Figure 82 – ASDU: P_AC_NA_1 Parameter activation.112
Figure 83 – ASDU: F_FR_NA_1 File ready.113
Figure 84 – ASDU: F_SR_NA_1 Section ready.114
Figure 85 – ASDU: F_SC_NA_1 Call directory, select file, call file, call section.115
Figure 86 – ASDU: F_LS_NA_1 Last section, last segment .116
Figure 87 – ASDU: F_AF_NA_1 ACK file, ACK section.117
Figure 88 – ASDU: F_SG_NA_1 Segment.118
Figure 89 – ASDU: F_DR_TA_1 Directory.119
Figure 90 – Hierarchical presentation of the allocation of common addresses of ASDUs
to LRUs (example) .123
Figure 91 – Sequential procedure of station interrogation to all LRUs of a specific
controlled station (example).124
Figure 92 – General counter model.125
Figure 93 – Sequential procedure of spontaneously transmitted integrated totals
(mode A) .126
Figure 94 – Sequential procedure of interrogation of integrated totals (mode B) .127
Figure 95 – Sequential procedure of memorizing of integrated totals without reset
(mode C).128
Figure 96 – Sequential procedure of memorizing of integrated totals with reset
(mode C).128
Figure 97 – Addressing of files (example) .130
Figure 98 – Request from protection equipment .131
Figure 99 – Request from substation automation system.132

– 6 – 60870-5-101  IEC:2003(E)
Figure 100 – Structure of disturbance data of a protection equipment.133
Figure 101 – Allocation of data types (ASDUs) of IEC 60870-5-103 to the sections of
disturbance data files .134
Figure 102 – Allocation of the data unit type 23 to the directory F_DR_TA_1 .135
Figure 103 – Sequential procedure, transmission of the directory .138
Figure 104 – Sequential procedure, transmission of disturbance data files.139-141
Figure 105 – Record of sequences of events in the section of a data file .143
Figure 106 – Sequential procedure, transmission of sequences of events.144
Figure 107 – Section of a data file containing sequences of recorded analogue values .145
Figure 108 – Sequential procedure, transmission of sequences of recorded analogue
values .147
Figure 109 – Sequential procedure, read procedure .148
Figure B.1 – Shift of a character caused by an inverted additional line idle bit.177
Figure B.2 – Relation of even and odd bit pattern to the parity bit .177
Figure B.3 – Shifted bit pattern .178
Table 1 – Selection from ITU-T V.24 or ITU-T V.28.13
Table 2 – Selection from ITU-T X.24 or ITU-T X.27 for interfaces to synchronous digital
signal multiplexers.14
Table 3 – Permissible combinations of unbalanced link layer services.16
Table 4 – Permissible combinations of balanced link layer services.20
Table 5 – Time out intervals (T ) depending on frame length, transmission speed and
project specific parameters (examples) .25
Table 6 – Time out intervals (T ) depending on frame length, transmission speed
and project specific parameters (examples) .26
Table 7 – Effects of the different resets .26
Table 8 − Semantics of TYPE IDENTIFICATION – Process information in monitor direction .30
Table 9 – Semantics of TYPE IDENTIFICATION – Process information in control direction .31
Table 10 – Semantics of TYPE IDENTIFICATION – System information in monitor direction .32
Table 11 – Semantics of TYPE IDENTIFICATION – System information in control direction .32
Table 12 – Semantics of TYPE IDENTIFICATION – Parameter in control direction.32
Table 13 – Semantics of TYPE IDENTIFICATION – File transfer.33
Table 14 – Semantics of CAUSE OF TRANSMISSION .40
Table 15 – ASDUs in the monitor direction which may transmit objects with equal
information object addresses .44
Table 16 – Respond priorities of the controlled station .120
Table 17 – ASDUs involved in the station interrogation procedure .122
Table 18 – Allocation of type identification to type identification (IEC 60870-5-101 and
IEC 60870-5-103) .136
Table 19 – Example for the definition of information object addresses (directory or
subdirectory) .136
Table 20 – Allocation of SOF status of file to SOF status of fault (IEC 60870-5-101 and
IEC 60870-5-103) .137
Table 21 – Type identifications for background scan .148

60870-5-101  IEC:2003(E) − 7 −
INTERNATIONAL ELECTROTECHNICAL COMMISSSION
___________
TELECONTROL EQUIPMENT AND SYSTEMS –
Part 5-101: Transmission protocols –
Companion standard for basic telecontrol tasks
FOREWORD
1) The IEC (International Electrotechnical Commission) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of the IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, the IEC publishes International Standards. Their preparation is
entrusted to technical committees; any IEC National Committee interested in the subject dealt with may
participate in this preparatory work. International, governmental and non-governmental organizations liaising
with the IEC also participate in this preparation. The IEC collaborates closely with the International Organization
for Standardization (ISO) in accordance with conditions determined by agreement between the two
organizations.
2) The formal decisions or agreements of the IEC on technical matters, express as nearly as possible, an
international consensus of opinion on the relevant subjects since each technical committee has representation
from all interested National Committees.
3) The documents produced have the form of recommendations for international use and are published in the form
of standards, technical specifications, technical reports or guides and they are accepted by the National
Committees in that sense.
4) In order to promote international unification, IEC National Committees undertake to apply IEC International
Standards transparently to the maximum extent possible in their national and regional standards. Any
divergence between the IEC Standard and the corresponding national or regional standard shall be clearly
indicated in the latter.
5) The IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with one of its standards.
6) Attention is drawn to the possibility that some of the elements of this International Standard may be the subject
of patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 60870-5-101 has been prepared by IEC technical committee 57:
Power system control and associated communications.
This second edition cancels and replaces the first edition published in 1995, its amendments 1
(2000) and 2 (2001) and constitutes a technical revision.
The text of this standard is based on the following documents:
FDIS Report on voting
57/605/FDIS 57/623/RVD
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
The committee has decided that the contents of this publication will remain unchanged until
2005. At this date, the publication will be
• reconfirmed;
• withdrawn;
• replaced by a revised edition, or
• amended.
A bilingual version of this publication may be issued at a later date.

– 8 – 60870-5-101  IEC:2003(E)
TELECONTROL EQUIPMENT AND SYSTEMS –
Part 5-101: Transmission protocols –
Companion standard for basic telecontrol tasks
1 Scope and object
This part of IEC 60870-5 applies to telecontrol equipment and systems with coded bit serial
data transmission for monitoring and controlling geographically widespread processes. It
defines a telecontrol companion standard that enables interoperability among compatible
telecontrol equipment. The defined telecontrol companion standard utilizes standards of the
IEC 60870-5 series of documents. The specifications of this standard present a functional
profile for basic telecontrol tasks. Further companion standards, based on the IEC 60870-5
series are under consideration.
This standard defines ASDUs with time tags CP24Time2a which includes three octets binary
time from milliseconds to minutes. In addition to these specifications, ASDUs with time tags
CP56Time2a, which includes seven octets binary time from milliseconds to years, are defined
in this standard (see 6.8 of IEC 60870-5-4 and 7.2.6.18 of this standard).
ASDUs with time tags CP56Time2a are used when the controlling station is not able to add the
time from hours to years unambiguously to the received ASDUs which are tagged from
milliseconds to minutes. This may happen when using networks with uncertain transmission
delays or if temporary failure of a network occurs.
Although this companion standard defines the most important user functions, other than the
actual communication functions, it cannot guarantee complete compatibility and interoperability
between equipment of different vendors. An additional mutual agreement is normally required
between concerned parties regarding the methods of use of the defined communication
functions, taking into account the operation of the entire telecontrol equipment.
Standards specified in this standard are compatible with standards defined in IEC 60870-5-1 to
IEC 60870-5-5 (see Clause 2).
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 60050(371):1984, International Electrotechnical Vocabulary (IEV) − Chapter 371:
Telecontrol
IEC 60870-1-1:1988, Telecontrol equipment and systems – Part 1: General considerations −
Section 1: General principles
IEC 60870-5-1:1990, Telecontrol equipment and systems − Part 5: Transmission protocols −
Section 1: Transmission frame formats
IEC 60870-5-2:1992, Telecontrol equipment and systems − Part 5: Transmission protocols −
Section 2: Link transmission procedures

60870-5-101  IEC:2003(E) − 9 −
IEC 60870-5-3:1992, Telecontrol equipment and systems – Part 5: Transmission protocols –
Section 3: General structure of application data
IEC 60870-5-4:1993, Telecontrol equipment and systems – Part 5: Transmission protocols –
Section 4: Definition and coding of application information elements
IEC 60870-5-5:1995, Telecontrol equipment and systems – Part 5: Transmission protocols –
Section 5: Basic application functions
IEC 60870-5-103:1997, Telecontrol equipment and systems – Part 5-103: Transmission
protocols – Companion standard for the informative interface of protection equipment
ISO/IEC 8824-1:2000, Information technology – Abstract Syntax Notation One (ASN.1):
Specification of basic notation
ITU-T V.24:2000, List of definitions for interchange circuits between data terminal equipment
(DTE) and data circuit-terminating equipment (DCE)
ITU-T V.28:1993, Electrical characteristics for unbalanced double-current interchange circuits
ITU-T X.24:1988, List of definitions for interchange circuits between Data Terminal Equipment
(DTE) and Data Circuit-terminating Equipment (DCE) on public data networks
ITU-T X.27:1996, Electrical characteristics for balanced double-current interchange circuits
operating at data signalling rates up to 10 Mbit/s
IEEE 754:1985, Binary floating-point arithmetic
3 Terms and definitions
For the purpose of this part of IEC 60870-5, the following definitions apply.
3.1
companion standard
a companion standard adds semantics to the definitions of the basic standard or a functional
profile. This may be expressed by defining particular uses for information objects or by defining
additional information objects, service procedures and parameters of the basic standard
NOTE Companion standards do not alter the standards to which they refer, but make explicit the relationship
between those used together for a specific domain of activity.
3.2
group (of information objects)
selection of COMMON ADDRESSES or INFORMATION ADDRESSES which is specifically defined for a
particular system
3.3
control direction
direction of transmission from the controlling station to a controlled station
3.4
monitor direction
direction of transmission from a controlled station to the controlling station

– 10 – 60870-5-101  IEC:2003(E)
3.5
system parameter
a system parameter (or system-specific parameter) is valid for the complete telecontrol system
which uses this companion standard. The telecontrol system consists of the entire controlled
and controlling stations which may be connected via different network configurations
3.6
network-specific parameter
a network-specific parameter is valid for all the stations which are connected via a particular
network configuration
3.7
station-specific parameter
a station-specific parameter is valid for particular stations
3.8
object-specific parameter
an object-specific parameter is valid for a particular information object or a specific group of
information objects
4 General rules
This Clause provides general rules for constructing companion standards for the transmission
protocol of specific telecontrol systems, using the IEC 60870-5 series protocol.
These general rules are applied in the following Subclauses.
4.1 Protocol structure
The IEC 60870-5 series protocol is based on the three-layer reference model “Enhanced
Performance Architecture” (EPA), as specified in Clause 4 of IEC 60870-5-3.
The physical layer uses ITU-T recommendations that provide binary symmetric and
memoryless transmission on the required medium in order to preserve the high level of data
integrity of the defined block encoding method in the link layer.
The link layer consists of a number of link transmission procedures using explicit LINK
PROTOCOL CONTROL INFORMATION (LPCI) that are capable of carrying APPLICATION SERVICE
DATA UNITs (ASDUs) as link-user data. The link layer uses a selection of frame formats to
provide the required integrity/efficiency and convenience of transmission.
The application user layer contains a number of “Application Functions” that involve the
transmission of APPLICATION SERVICE DATA UNITs (ASDUs) between source and destination.
The application layer of this companion standard does not use explicit APPLICATION PROTOCOL
CONTROL INFORMATION (APCI). This is implicit in the contents of the ASDU DATA UNIT IDENTIFIER
field and in the type of link service used.
Figure 1 shows the Enhanced Performance Architecture model (EPA) and the selected
standard definitions of the companion standard.

60870-5-101  IEC:2003(E) − 11 −

Selected application functions
of
User process
IEC 60870-5-5
Selected application information elements
of
IEC 60870-5-4
Application (layer 7)
Selected application service data units
of
IEC 60870-5-3
Selected link transmission procedures
of
IEC 60870-5-2
Link (layer 2)
Selected transmission frame formats
of
IEC 60870-5-1
Selected ITU-T recommendations Physical (layer 1)
IEC  084/03
Figure 1 – Selected standard provisions of the defined
telecontrol companion standard
4.2 Physical layer
The companion standard specifies ITU-T recommendations which define the interfaces
between data circuit terminating equipment (DCE) and data terminating equipment (DTE) of the
controlling and the controlled station (see Figure 2, as well as Figure 2 of IEC 60870-1-1).
Data circuit
Data Terminal Data Circuit Data Circui
...