1、INTERNATIONAL STANDARD ISO/IEC 9549 First edition 1990-10-15 Information technology - Galvanic isolation of balanced interchange circuits SystPmes de traitement de /information - isolation galvanique des circuits dhchange kquilibrh Reference number ISWIEC 9549:1990(E) ISOliEC 9549:1990(E) Foreword I
2、S0 (the International Organization for Standardization) and IEC (the International Electrotechnical Commission) form the specialized system for worldwide standardization. National bodies that are members of IS0 or IEC participate in the development of International Standards through technical commit
3、tees established by the respective organization to deal with particular fields of technical activity. IS0 and IEC technical com- mittees collaborate in fields of mutual interest. Other international or- ganizations, governmental and non-governmental, in liaison with IS0 and IEC, also take part in th
4、e work. In the field of information technology, IS0 and IEC have established a joint technical committee, ISO/IEC JTC 1. Draft International Standards adopted by the joint technical committee are circulated to national bod- ies for voting. Publication as an International Standard requires ap- proval
5、 by at least 75 % of the national bodies casting a vote. International Standard ISO/IEC 9549 was prepared by Joint Technical Committee ISO/IEC JTC 1, Information technology. Annex A of this International Standard is for information only 8 ISOllEC 1990 All tights reserved. No part of this publicanon
6、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. ISO/IEC Copyright Office l Case Postale 56 l CH-1211 Genkve 20 l Switzerland Printed in Switzerland ISOllEC 9549:1990(E) Introd
7、uction This international Standard specifies a method of galvanically isolating signal exchanges on balanced interchange circuits using optocoupler integrated circuit technology. It may be applied for data transmission in a two-condition code (e.g. NRZ). Galvanic isolation of interchange circuits is
8、 required whenever the intercommunicating devices are connected t0 different mains supplies. In this case, the ground potential difference between the earthing systems frequently iS higher than the common mode voltage specified for the interchange circuit receiver. Transmission errors and even damag
9、e to the receiver may be the result. The optocoupler type of galvanic isolation may also be used when high external signal interferences have to be minimized. This situation may exist with iong interchange circuits and operation at higher data signalling rates. The specifications of this Internation
10、al Standard are compatible with both IS0 8482 (multipoint connection) and CCITT Recommendation V.11 (point-to-point connection) because of appiication flexibility and the fact that there is not much difference in the parameters for the component design. Bidirectional data transmission is provided an
11、d requires the implementation of an isdated generator and an isolated receiver. Their unbalanced interfaces are not specified in order to provide flexibility for implementations and device manufacturers. iii INTERNATIONAL STANDARD ISOllEC 9549:1990(E) Information technology - Galvanic isolation of b
12、alanced interchange circuits 1 Scope 1 .l This International Standard specifies galvanic isolation of balanced interchange circuits using optocoupler integrated circuit technology and is provided for data transmission in the two-condition code (e.g. NRZ). The electrical characteristics are compatibl
13、e with both IS0 8482 and CCITT Recommendation V.11 NOTE - Compatible means to allow interoperation with devices having interchange circuits conforming to the electrical characteristics specified in the referenced standards. Annex A shows interoperation with CCITT Recommendation V. 11 interchange cir
14、cuits in a point-to-point environment. 1.2 The specifications are given in terms of parameters and measurements for an isolated generator and an isolated receiver. These components may be used in twisted pair 2-wire or 4-wire point-to-point connections up to 1 000 m or multipoint connections up to 5
15、00 m for speeds up to 2 Mbit/s for point-to-point connections and 1 Mbit/s for multipoint connections. For data signalling rates up to 20 kbit/s, device manufacturers may optimize their component design. 1.3 Options are provided to meet special application requirements, such as - isolated generator
16、high impedance control; - isolated receiver circuit failure detection capability; - line termination in point-to-point configuration 1.4 This International Standard does not describe a complete equipment interface in terms of mechanical, electrical and functional /procedural specifications. 2 Normat
17、ive references The following standards contain provisions which, through reference in this text, constitute provisions Of this International Standard. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this Interna
18、tional Standard are encouraged to investigate the possibility of applying the most recent editions of the standards listed below. Members of IEC and IS0 maintain registers of currently valid International Standards. IS0 8482 : 1987, Information processing systems - Data communication - Twisted pair
19、multipoint interconnections. CCITT Recommendation V. 11 : 1988, Electrical characteristics for balanced double-current interchange circuits for general use with integrated circuit equipment in the field of data communications. ISOllEC 95493 990(E) 3 Symbolic representation of optocoupler components
20、3.1 Isolated generator E 0 0 AB Balanced signal output C Zero volt reference interchange point D,D Floating power supply E Unbalanced station power supply F Unbalanced signal input Unbalanced high impedance control Isolated generator Figure 1 - Symbolic representation of isolated generator 3.2 Isola
21、ted receiver r - _- - I 7 1 , Unced Interface A 8 C-L-J / it 1 - I t -Ggnal grounds- 7 -i D D E A,B Balanced signal input A,B + B” Balanced terminated signal input option C Zero volt reference interchange point D,D Floating power supply E Unbalanced station power supply F Unbalanced signal output R
22、Isolated receiver Figure 2 - Symbolic representation of isolated receiver 2 ISOllEC 9549:1990(E) 4 Polarities and significant levels 4.1 Balanced signal output / input The generator polarities and receiver differential significant levels correspond to those of subclause 7 of IS0 8482 and clause 4 of
23、 CCI?l Recommendation V. 11. Table 1 - Receiver differential significant levels Data circuits Control and timing circuits v/f V&r 43 v v*,- VB + 0,3 v Mark, 1 Space, 0 OFF ON 4.2 Unbalanced signal output / input The generator polarities and receiver differential significant levels are in accordance
24、with the technology used on the unbalanced interface. 5 Isolated generator characteristics 5.1 Balanced signal output A generator component is measured in the active low impedance state in accordance with the measurement arran- gements in IS0 8482. The generator component may be supplied for the mea
25、surements by an appropriate single-rail power supply for the unbalanced input side and the balanced output side. Alternatively a floating power Supply may be used for the balanced output side, The tests are made for either binary state. For these states the symbols USed in IS0 8482 are I VI and lvl,
26、 respectively. 51.1 Open circuit vottage, V. As in subclause 8.1 of IS0 8482 51.2 Terminated output voltage, Vt As in subclause 8.3 of IS0 8482 5.1.3 Offset voltage, Vos As in subclause 8.2 of IS0 8482 51.4 Rise time, fr , and imbalance voltage, Ve As in subclause 8.4 of IS0 8482 3 ISOllEC 9549:1990
27、(E) 5.2 Inactive high impedance state measurements option 5.2.1 Static measurements When in the high impedance state and with test loads of 50 r connected between each generator output point and point C, the magnitude of the voltage V logical condition of the generator input 6 measured between point
28、s A and B shall not exceed 4 mV whatever the ata lead. When the generator is in the high impedance state, with voltages ranging between -8 V and +G V applied between each output point and point C, the magnitude of the output leakage currents /,a and lxb shall not exceed 150 uA. The same situation ap
29、plies in the power-off condition. 5.2.2 Dynamic measurements During transitions of the generator output between the low impedance state and the high impedance state, the differential signal measured across a 1 OOfl test load connected between the generator points A and B shall be such that the ampli
30、tude changes from 10% to 90% of the steady state voltage in less than 10 us. 5.3 Unbalanced signal input Reference measurements for verification of the parameters at the unbalanced input side should be made in accordance with the technology used and are not specified in this International Standard.
31、6 Isolated receiver characteristics 6.1 Balanced signal input A receiver component is measured in accordance with the measurement arrangements shown in subclause 9 of IS0 8482 (without termination). The receiver component may be supplied for the measurements by an appropriate single-rail power suppl
32、y for the unbalanced output side and the balanced input side. Alternatively, a floating power supply may be Used for the ba!anced input side. The tests are made for either binary state. 6.1 .l Input sensitivity As in subclause 9.1 of IS0 8482 6.1.2 Input balance As in subclause 9.2 of IS0 8482 6.2 C
33、able termination option The cable termination resistance shall not be less than 120 Sz. 6.3 Circuit failure detection option The interpretation of a fault condition by an isolated receiver depends on its application. The following two types, as specified in clause 9 of CCITT Recommendation V. 11, sh
34、all be selectable: -Type 1: Data circuits assume a binary 1 state. Control and timing circuits assume an OFF condition. - Type 2: Data circuits assume a binary 0 state. Control and timing circuits assume an ON condition. ISOliEC 9549:1990(E) 6.4 Unbalanced signal output Reference measurements for ve
35、rification of the parameters at the unbalanced output side should be made in accordance with the technology used and are not specified in this International Standard. 7 Fault condition tests The components are tested according to the measurement arrangements shown in subclause 10 of IS0 8482. NO dam
36、age shall occur due to a single fault condition. 7.1. Generator short circuit As in subclause 10.1 of IS0 8482 7.2 Generator contention As in subclause 10.2 of IS0 S4S2 7.3 Generator current limitation As in subclause 10.3 of IS0 8482 7.4 Transient over-voltage As in subclause 10.4 of IS0 8482 8 Int
37、erconnection configuration Shielded twisted pair cables with wires 0,4 mm to 0, mm in diameter are recommended to be used in all Con- figurations. Examples of configurations are illustrated in CClll Recommendation V.11, figure 3, for point-to-point applications and in IS0 3482, figures 2 and 3, for
38、multipoint applications, respectively. 9 Optocoupler component isolation The resistance between the unbalanced input side and the balanced output side of an isolated genera$X and between the balanced input side and the unbalanced output side of an isolated receiver shall be 10 fiat 500 V (a.c.) unde
39、r operational conditions. The optocoupler components, when connected to their associated power supplies, as shown in figure 3, shall withstand without breakdown a voltage of 2,5 kV(rms) for a minimum of 1 min. NOTE - Higher voltage may apply where safety is under consideration. (e g. IEC 950) 5 ISOA
40、EC 9549:1990(E) 10 Signal distortion The individual distortion, measured for Mark / Space reversals at the applied data signalling rate, using the measu- rement arrangements in figure 3 (balanced terminated signal input) shall be 5 10 % . Figure 3 - Individual distortion measurement arrangement 11 E
41、nvironmental constraints In order to operate a balanced interchange circuit with an isolated generator and an isolated receiver no Special en- vironmental conditions apply. Since the total balanced circuit is floating within the range of specified breakdown Vol- tage in subclause 9 and the isolated
42、receiver usually includes an internal shield, the operation of the interchange Cir- cuit should not be affected by longitudinal induced random noise. 6 ISOllEC 9549:1990(E) ANNEX A (informative) Application of an isolated generator/receiver with a CCllT Recommendation V. 11 generator/receiver in poi
43、nt-to- point connection Isolated generator Unbalancad i &gnal ground Floatmg power supply El Figure A. 1 - Isolated generator interconnection with V. 11 receiver Mated remver V 11 generator !- - , 7 1 I I I I -L - c c!& Signal ground 0 0 1r 1 E floatmg power supply Figure A.2 - V. 11 generator interconnection with isolated receiver ISOllEC 9549:1990(E) - - UDC 681.327.8:621.316.5 Descriptors: data processing equipment, electronic circuits, integrated circuits, optoelectronic devices, specifications, tests Price based on 7 pages
