1、BRITISH STANDARD BS 7404-3: 1991 IEC 870-3: 1989 Telecontrol equipment and systems Part 3: Specification for interfaces (electrical characteristics) (Implementation of CENELEC HD546.3S1)BS7404-3:1991 This British Standard, having been prepared under the directionof the Power Electrical Engineering S
2、tandardsPolicy Committee, waspublished underthe authority of the Standards Boardand comes intoeffect on 31 October 1991 BSI 08-1999 The following BSI references relate to the work on this standard: Committee reference PEL/89 Draft for comment 89/27225 DC ISBN 0 580 20109 0 Committees responsible for
3、 this British Standard The preparation of this British Standard was entrusted by the Power Electrical Engineering Standards Policy Committee (PEL/-) to Technical Committee PEL/89, upon which the following bodies were represented: Association of Consulting Engineers BAMEMA (BEAMA) BEAMA Ltd. EEA (the
4、 Association of Electronics, Telecommunications and Business Equipment Industries) Electricity Supply Industry in United Kingdom GAMBICA (BEAMA Ltd.) North of Scotland Hydro-Electric Board Telecommunication Engineering and Manufacturing Association Transmission and Distribution Association (BEAMA Lt
5、d.) Amendments issued since publication Amd. No. Date CommentsBS7404-3:1991 BSI 08-1999 i Contents Page Committees responsible Inside front cover National foreword ii 1 Scope 1 2 Object 1 3 Types of information 1 4 Interface between telecontrol equipment and process equipment 2 5 Interface between t
6、elecontrol equipment and operators equipment 3 6 Interfaces between telecontrol equipment and communication subsystems 4 7 Interface between telecontrol equipment and other data processing equipment 5 Annex ZA (normative) Other international publications quoted in this standard withthereferences of
7、the relevant European publications 17 Figure 1 Interfaces between modules in a typical telecontrol system 11 Figure 2 Level ranges of binary signals 12 Figure 3 Parameters of a binary signal 12 Figure 4 Level ranges of analog signals 13 Figure 5 Binary input circuits 14 Figure 5a Active binary input
8、 circuit 14 Figure 5b Passive binary input circuit 14 Figure 6 Binary output circuits 15 Figure 6a Passive binary output circuit 15 Figure 6b Active binary output circuit 15 Figure 7 Analog input and output circuits 16 Figure 7a Analog input circuit 16 Figure 7b Analog output circuit 16 Table 1 Exam
9、ples of relationships between signals and types of information 6 Table 2 Nominal voltages for binary signals 6 Table 3 Current classes for binary input signals 6 Table 4 Current classes for binary output signals 6 Table 5 Nominal values for analog signals 6 Table 6 Interference voltage limits and in
10、sulation requirements for binary signals 7 Table 7 Interference voltage limits and insulation requirements for analog signals 8 Table 8 Active binary input signals 8 Table 9 Passive binary input signals 9 Table 10 Passive binary output signals 9 Table 11 Active binary output signals 10 Table 12 Anal
11、og input and output signals 10 Table 13 Relationship between physical distance (DCE/DTE) and maximum transmission speed 10 Table 14 CCITT, ISO and EIA recommendations/standards for DCE-DTE interfaces 11 Publication(s) referred to Inside back coverBS7404-3:1991 ii BSI 08-1999 National foreword This P
12、art of BS 7404 has been prepared under the direction of the Power Electrical Engineering Standards Policy Committee and is identical with IEC Publication 870-3:1989 “Telecontrol equipment and systems Part 3: Interfaces (electrical characteristics)”, published by the International Electrotechnical Co
13、mmission (IEC) which has been endorsed by CENELEC as HD 546.3 S1:1991. The International Standard does not give the up-to-date relation between this Part of the IEC standard and the other published and envisaged Parts and Sections. Other Parts and Sections of this British Standard are as follows. Pa
14、rt 1: General considerations; Section 1.1: General principles; Section 1.2: Guide for specifications; Section 1.3: Glossary; Section 1.4: Basic aspects of telecontrol data transmission 1) ; Part 2: Operating conditions; Section 2.1: Specification for classes of environmental conditions and power sup
15、plies; Section 2.2: Specification for electromagnetic compatibility and erosive and corrosive influences 2) ; Part 3: Specification for interfaces (electrical characteristics); Part 4: Specification for performance; Part 5: Transmission protocols; Section 5.1: Specification for transmission frame fo
16、rmats; Section 5.2: Specification for transmission procedures 3) ; Section 5.3: Specification for structure of application data 4) ; Section 5.4: Specification for coding specifications of application data 5) ; Part 6: Specification for telecontrol protocols compatible with ISO and CCITT standards 2
17、) . The Technical Committee has reviewed the provisions of IEC 50(371), IEC 225-4 and IEC 495, to which reference has been made in the text, and has decided that they are acceptable for use in conjunction with this British Standard. 1) Will be published after IEC 870-1-4 has been published. 2) Not y
18、et published, envisaged as future work by IEC. 3) Will be published after IEC 870-5-2 has been published. 4) Will be published after IEC 870-5-3 has been published. 5) Will be published after IEC 870-5-4 has been published. Cross-references International Standard Corresponding British Standard IEC 6
19、25 BS 6146 An interface system for programmable measuring instruments (byte serial, bit parallel) (Identical) IEC 870-4:1990 BS 7404 Telecontrol equipment and systems Part 4:1991 Specification for performance (Identical)BS7404-3:1991 BSI 08-1999 iii A British Standard does not purport to include all
20、 the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i to i
21、v, pages1to 18, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover.iv blankBS7404-3:1991 BSI 08-1999 1 1 Scope This series of standards applies to
22、 telecontrol equipment and systems with coded bit serial data transmission for monitoring and controlling geographically widespread processes. 2 Object This part defines electrical interface characteristics (e.g. signals, impedances, etc.) which have to be met at the shared boundaries (seeFigure 1)
23、between: telecontrol equipment and external equipment connected to: process equipment (e.g. sensors, actuators); operators equipment; telecontrol equipment and transmission line (channel) where “data circuit terminating equipment” (i.e. DCE-MODEM) is packaged as an integral part of the telecontrol e
24、quipment, or telecontrol equipment and “data circuit terminating equipment”, where the latter is not packaged as an integral part of the telecontrol equipment; different parts of the equipment within the telecontrol system and other data processing equipment. The interfaces shall be defined independ
25、ently from the functional layout of the system or its subsystems. Information in this part refers only to operating conditions. The following subjects are outside the object of this part: interface between external power source and the telecontrol equipment; logical interfaces and interface protocol
26、s; interface testing conditions and procedures. 3 Types of information Two basic types of information are presented to the interfaces: digital and analog. Both types are conveyed over the interfaces by means of signals which are in parallel, serial or stand alone form. Examples of the relationship b
27、etween these signals and types of information are given in Table 1. Each of these signals can be used as either an input or an output. An input is a signal representing information generated outside the specific equipment involving the interface being considered. Otherwise, it is an output. 3.1 Digi
28、tal information Digital information is used for characterizing states which vary in discrete modes. The information may pass the interface in parallel or serial form. 3.1.1 Types of digital information (examples) 3.1.1.1 Single-point information A single-point information (see IEV 371-02-07 6) ) ema
29、nates from a one bit binary information source, for example from an alarm contact with two determined states. This information is presented to the interface by a stand alone binary signal. 3.1.1.2 Double-point information Two bit information sources such as circuit breakers or isolator contacts repr
30、esent double-point information (see IEV 371-02-08). They are presented to the interface by a pair of binary signals. Two states, represented by the bit pairs 01 and 10 characterize two determined states (OFF/ON and ON/OFF), while the bit pairs 00 and 11 characterize two indeterminate states (OFF/OFF
31、 and ON/ON) which indicate either an intermediate state (see IEV 371-02-09), a faulty state (see IEV 371-02-10) or a failure in the circuitry. 3.1.1.3 Multipoint information coded information Digital information sources which require coded information (e.g. transformer tap positions, meter readings
32、and set point commands). The information can be transferred by associated signals in parallel or serial form. 3.1.2 Representation of digital information Digital information is represented by individual binary signals with two distinct exclusive levels. 3.1.2.1 Signal levels The signal level can ass
33、ume different ranges (Figure 2): range (1): nominal range. The normal operating condition of the equipment; range (2): intermediate range. A transitory area between the upper and lower limits of the nominal range(1). If the signal persists for longer than a predetermined time in this area, a failure
34、 condition is said to exist; range (3): fault state range. Anomalous operating conditions which may cause malfunction of the equipment. If the signal level exceeds upper or lower damaging limits, a persistent malfunction could be caused. 6) International Electrotechnical Vocabulary (IEV) IEC 50(371)
35、.BS7404-3:1991 2 BSI 08-1999 In order to ensure correct equipment interfacing, the nominal range of the outputs should be smaller than the nominal range of the inputs. 3.1.2.2 Signal duration The duration of binary signals can be divided into two categories: a) When the binary information source con
36、trols the duration of the associated two discrete nominal signal levels: b) When a status change in the binary information source triggers a pulse signal: The pulse signal assumes one of the two nominal levels for a predetermined time. It is used to characterize incremental or transient types of inf
37、ormation sources. 3.1.3 Dynamic characteristics of signals These are defined in terms of duration, recovery time and transition time (Figure 3). 3.1.4 Specifications Specifications for binary signals are given in clauses4 to 7. The main items are: nominal levels (voltage or current); location and im
38、pedance of generating circuit (in or out of the equipment); shape of pulse (level, transition time, duration, polarity, residual ripple); type of galvanic isolation and interference voltages limits (normal mode, common made). 3.2 Analog information 3.2.1 Representation of analog information An analo
39、g signal is associated with a quantity which may vary between predetermined values. 3.2.2 Single/double polarity Two types of analog signals are to be considered: unipolar: A variable quantity with one polarity only (e.g. a voltage). The signal magnitude assumes one polarity only (e.g. 0 mA to 5 mA
40、or 4 mA to 20 mA); bipolar: A variable quantity which can assume either positive or negative polarity (e.g. load flow). The signal magnitude can assume either positive or negative polarity (e.g. p 5 mA to +5 mA). 3.2.3 Signal levels The magnitude of an analog signal can assume two ranges (Figure 4):
41、 range (1): nominal range. Normal operating conditions of the equipment, including the eventual operational overload; range (2): malfunction range. Anomalous operating conditions which may cause a malfunction of the equipment. If the signal level exceeds upper and lower damaging limits, a persistent
42、 malfunction could be caused. 3.2.4 Specifications Specifications for analog signals are given in clauses4 to 7. The main items are: range limits (voltage or current); load impedances (maximum for current, minimum for voltage); type of galvanic isolation and interference voltages limits (normal mode
43、, common mode). Neither accuracy nor signal bandwidth (e.g. rate of change) are specified, since they are performance characteristics (IEC 870-4 in preparation). 4 Interface between telecontrol equipment and process equipment This interface is the boundary line where information passes between telec
44、ontrol equipment and process equipment in the controlled station (Figure 1). The information is exchanged by means of binary or analog signals. The information transferred from the process equipment to the telecontrol equipment represents the “input”. The information transferred in the opposite dire
45、ction represents the “output”. Four categories of signals require to be considered: binary input signals; binary output signals; analog input signals; analog output signals. 4.1 General characteristics The following information refers to inputs as well as outputs. For example: generator in operation
46、 = signal level H (high); generator out of operation = signal level L (low). For example: acquisition of fleeting information (see IEV 371-02-11) or incremental information (see IEV 371-02-06) or output of pulse command (see IEV 371-03-04). For example: The signal range 0 mA to 10 mA may represent a
47、 variable source information within the range 0 kV to 130 kV.BS7404-3:1991 BSI 08-1999 3 Nominal voltage and current classes for binary signals are shown in Table 2, Table 3 and Table 4. Nominal values of currents and voltages for analog signals are shown in Table 5. Interference voltages limits and
48、 insulation requirements for binary and analog signals are given in Table 6 and Table 7. These voltages indicate the limits within which the equipment: a) will continue to operate correctly (operating limits); b) will not be damaged (damaging limits). When inputs and outputs are not insulated from g
49、round, only normal mode voltages shall be used. 4.2 Binary input signals Binary input signals fall into two main categories: For reliable operation, the currents circulating through contacts and loads shall be specified. Specifications for binary input signals are given in Table 8 and Table 9. 4.3 Binary output signals Binary output signals fall into two main categories, namely: Specifications for binary output signals are given i
