1、= 3404583 OLOO12L L4T W A EUROPEAN STmARD NORNE EUR0PEE?NE EuRopAIscHE NORM EN 602370-5-1 September 1993 UDC 621.398 : 621.316.1 : 681.3.04 Descriptors: Telecontrol, data transmission, open system interconnection, protocol, data stmcture, frame, format English version Telecontrol equipment and syste
2、ms Part 5: ?Ik.ansmission protocols Section One: ?k.ansmission ke formats (IEC 870-5-1 : 1990) Matriels et systmes de tlconduite Partie 5: Protocoles de transmission Section un: Formats de trames de transmission Fernwirkeinrichtungen und Fernwirksysteme Teil 5: bertragungsprotokolle Hauptabschnitt e
3、ins: Telegrammformate (CE1 870-51 : 1990) (IEC 870-51 : 1990) This European Standard was approved by CENELEC on 1993-07-06. CENELEC members are bound to comply with the CENKENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard
4、without any alteration. Up-todate lists and bibliographicd 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 (Enghsh, French, German). A version in any other langu
5、age 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 memberc are the national electrotechnicd committees of Austria, Belgium, Denmark, Finland, Fmnce, Germany, Greece,
6、Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. CENELEC European Committee for Electrotechnical Standardization Comit Europen de Normalisation Electrotechnique Europisches Komitee fr Elektrotechnische Normung Central Secretariat: rue
7、 de Stassart 35, B-1050 Brussels O 1993 Copyright reserved to CENELEC members Ref. No. EN 60870-5-1 : 1993 E A Page 2 EN 60870-5-1 : 1993 Foreword The CENELEC questionnaire procedure, performed for nding out whether or not the international Standard IEC 870-51 : 1990 could be accepted without textua
8、l changes, has shown that no common modincations were necessary for the acceptance as European Standard. The reference document was submitted to the CENELEC members for formal vote and was approved by CENELEC as EN 60870-5-1 on 6 July 1993. The following dates were fixed - latest date of publication
9、 of an identical national standard (dop) 1994-0801 - latest date of withdrawal of conflicting national standards (dow) 1994-0801 Annexes designated normative are part of the body of the standard. In this standard, annex ZA is normative. TELECONTROL EQUIPMENT AND SYSTEMS Part 5: Transmission protocol
10、s Section One - Transmission frame formats INTRODUCTION This section highlights specific requirements and conditions for data transmission in telecontrol systems and shows ways to meet those require- ments. Existing standards for data transmission protocols are adopted where they fulfil the specific
11、 telecontrol requirements. In terms of the OS1 (Open System Interconnection) reference model of ISO-CCITT, which subdivides communication into seven layers, this spe- cifies standards for the two lowest layers, namely the physical layer and the link layer. In particular the document specifies format
12、s for bit serial frame transmission which comply with specified classes of data integrity. Publication 870-5-2: Section Two: Transmission Procedures (in pre- paration) will specify further standards for the link layer and for higher layers. This comprises dispositions for data contents within frames
13、, i .e. services in various traffic modes and for various link - and network configurations. The ultimate purpose of the communication function in process monitoring and control is to achieve maximum system consistency, .e. there should be no discrepancies between the physical states of process vari
14、ables and their image in the data base of the telecontrol system. This ultimate goal cannot be achieved completely. The laws of causality dictate that the information about process states is delayed and environmental noise or component failures may falsify the information. All that can be expected i
15、s that the communication allows a high degree of system consistency to be maintained. For this reason the data transmission method shall support upgraded reliable and efficient information throughput in particular for short and urgent messages. The exploitation of the installed bandwidth with respec
16、t to these two qualities is the critical measure for telecontrol protocols, because the available bandwidths are limited. In an imperfect environment, however, high data integrity and efficient data transmission are conflicting properties: increasing demands for data integrity can be fulfilled at th
17、e expense of decreasing net speed of inform- ation flow. It is necessary, therefore, to find an acceptable compromise between these two properties, based on an analysis of the requirements. A pre-supposition for analytical treatment is the objective measurement of the required properties. _ m 340458
18、3 OLOO124 959 m 870-5-1 0 IEC Data transport is only one function of the total system. The speed and integrity requirements of data transmission shall be chosen to be consistent with the accuracy of the total system, .e. all the system parameters should be matched. In addition to the required compro
19、mise between trans- mission speed and transmission integrity there are further conditions which influence the choice of an appropriate telecontrol protocol, as shown in the following diagram : Fonctionai requirements Required response Required Required Required da ta availability accu racy integrity
20、 time Telecontrol pro toco1 definitions Network configuration Network characteristics / Plant conditions Geographical situation Ba ndwi d t h (transmission speed) Bit error rate Kinds of information transfers Number of messages (system size) One-way/two-way data traffic (supervisory/super- visory an
21、d control system Y Kecommended protocol m 3404583 0100125 895 m 870-5-1 O IEC 1. Scope This series of standards applies to telecontrol equipment and systems with coded bit serial data transmission for monitoring and controlling geographically widespread processes. This standard covers asynchro- nous
22、 data transmission with half duplex and duplex link protocols operating with window size one for message transfers. 2. Object This section specifies the basic requirements for services to be provided by the link plus physical layers, for telecontrol applications. In particular it specifies standards
23、 on coding, formating and synchro- nizing data frames of variable and fixed lengths which meet specified data integrity requirements. The specified block codes are suited for the transmission of bit serial frames over binary symmetric transmission channels using a memoryless bit encoding method. Thi
24、s means that the signal speci- fication of each transmitted bit shall not depend on signals transmitted before that bit. Note.- Recommendations for data transmission services using other than memoryless bit encoding methods (for example digital pulse duration modulation (DPDM), HDLC, etc.) and duple
25、x link protocols with window sizes greater than one are under consi- deration. 3. Requirements for data transmission in telecontrol systems According to the basic goals of telecontrol systems and to the parti- cular environmental conditions, it is necessary that data transmission f u If ils the foll
26、owing requi rements : 3.1 High data integrity and data consistency Correct data transmission is required in the presence of harsh environmental conditions, such as electromagnetic interferences, differences in earth potential, ageing components and other sources of disturbance and noise incident on
27、the transmission path. Under these conditions it is necessary to provide efficient protection of messages against: - undetected bit errors; - undetected frame errors caused by synchronization errors; 870-5-1 0 IEC - undetected loss of information; - gain of unintended information (.e. simulation of
28、messages by noise); - separation or perturbation of coherent information 3.2 Short telecontrol transfer time (see I EV 371 -08-1 6) Provision of short information transmission times by application of efficient frame transmission protocols, particularly for event initiated messages over transmission
29、paths with limited bandwidth and with uncertain noise characteristics. 3.3 Support of bit oriented (code transparent) data transmission No code restrictions on user data are required. The data link pro- tocol accepts and transmits arbitrary bit sequence structures from the data source. 4. Quantified
30、 rating of data integrity A quantitative specification of the data integrity in information transport systems is achieved by evaluating the contributions of the complement of data integrity, the non integrity of data. Basically there are two sources causing non integrity of data in a receiving stati
31、on, namely : (i) residual error rate (see IEV 371-08-05) = number of undetected wrong messages total number of messages sent (i) rate of residual information loss (see IEV 371-08-09) = number of undetected lost messages total number of messages sent It is emphasized that only rates of undetected err
32、ors or losses contribute to the non integrity of information transmission. Detected errors and losses are handled by predefined strategies such as auto- matic retransmission or reports to the user. They may affect the system availability as a whole but, in reporting these errors, the data transmissi
33、on protocol has fulfilled its function. 4 3404583 OLOOL27 bb8 870-5-1 0 IEC 4.1 Quantitative requirements for data integrity in telecontrol systems Three different data integrity classes Il, 12 and 13 have been estab- lished for telecontrol data transmission. The use of each class depends on the nat
34、ure of the data. Figure 1 shows a graphical representation of the upper limits of the residual error rate R depending on the bit error rate (see IEV 371-08-01) for these three classes. The graphs end at the bit error rate p = 0.5, the case of arbitrary bit reception, where no signal and only noise i
35、s received. The slope of the curves for p 0 Y CYrnC - . a U O O Y U O -4 P Y- O f Y Q c a 4 II C - VI Y .ri n Y o a L o - C O + .d m L Y- C U O f o 4 Co Il I i it- I U -4 t .a rl 4. t Co N rl - e- N o rl W II Y 4. - 1 I i Co - t O N rl U N o d Co II Y 4. H Y m E I O Y- Y O N U N U N U a mo cc .r( m
36、E+ EH m .- IV - XY om OE 4L mo r N U U o .4 +. .rl rl W u II c u a r I- Y QH O4 u0 LQ rl N t- U rl rl + U 14 870-5-1 IEC O0 L P 1 Frame length O specification -,/=- - O O 3404583 0100137 507 6.2.4.1 Format FT1. i: frames with Hamming distance 2 Formats with variable number of user data. Bit sequence
37、 on line - 1 2 3 4 5 6 7 8 9 10 11 Character 1 east si gni - ficant bit 1 7 Transmission ruies R1 - R2 - R3 - R4 - R5 - R6 - R7 - Line idle is binary 1. Each character has one start bit (binary O), 8 information bits, one even parity bit and one stop bit (binary 1). No line idle intervals are admitt
38、ed between characters of a frame. Upon detecting an error according to rule R7, a minimum interval of 22 line idle bits is required between frames. The actual block length L, .e. the number of subsequent user data octets is specified in the first character. L is a parameter in a binary notation whic
39、h ranges from O to 127. The first transmitted data bit of the first character (Dl) is zero. Start bit, stop bit, even parity bit, the data bit D1 = “O“ of the first character and, upon detecting an error, the line idle interval specified by R4 are checked by the receiver. The frame is rejected, if o
40、ne of these checks fails, otherwise the frame is released to the user. 6.2.4.2 Format FTl.2: frames with Hamming distance 4 Frames with fixed lengths and variable lengths, specified by the following Subclauses 6.2.4.2.1 and 6.2.4.2.2, may be transmitted over the same transmission lines. .- 3404583 O
41、lt00138 443 Frame check O Check sum P1 sum End character -P O O 1 1 O 1 O O O 1 1 870-5-1 0 IEC L 6.2.4.2.1 Format FTI .2 with fixed number of user data Bit sequence on line 1 2 3 4 5 6 7 8 9 10 11 Character Least signi- ficant bit 1 1 Start character User data 2 octets Stop bit Parity bit even 1 Oc
42、tet Start bit Frames with user data consist of a start character, a fixed number L of user data octets, a check sum (CS) and an end character. Transmission rules R1 - Line idle is binary 1. R2 - Each character has one start bit (binary O), 8 information bits, one even parity bit and one stop bit (bi
43、nary 1). R3 - No line idle intervals are admitted between characters of a frame. R4 - Upon detecting an error according to rule R6, a minimum interval of 33 line idle bits is required between frames. R5 - The sequence of user data characters is terminated by a 8 bits check sum (CS). The check sum is
44、 the arithmetic sum dis- regarding overflows (sum modulo 256) over all user data octets. R6 - The receiver checks: per character: the start bit, the stop bit and the even parity bit; per frame: the start character, the frame check sum and the end character and, upon detecting an error, the line idle
45、 interval specified by R4. The frame is rejected if one of these checks fails, otherwise it is released to the user. 3404583 OLOOL39 38T m 870-5-1 0 IEC Start, character Start- c ha ra c t er 6.2,4.2.2 FT I. 2 formats with variable number of user data T 1 O O O O 1 O 11 O 11 1 O L O L repeated O O O
46、 O 1 O 11 O 11 4 Header of fixed length iT - User data Frame check O Check sum sum End character + O O 1 1 O 1 O O O t Octet Start bit t Frames with user data consist of a start character, two equal characters which specify the number L of user data octets, a second start character, the user data, a
47、 frame check sum character and an end character. P1 1 1 1 Stop bit Parity bit L is a parameter in binary notation which ranges from O to 255. Transmission rules R1, R2, R3, R4 and R5: see Subclause 6.2.4.2.1. R6 - The receiver checks: per character: the start bit, the stop bit and the even parity bi
48、t; per frame: - the specified start character at the beginning and at the end of the frame header, - the identity of the two length specifications L, - that the number of received characters is equal to L + 6, - the frame check sum, - the end character, - upon detecting an error, the line idle inter
49、val specified by The frame is rejected if one of these checks fails, otherwise released to the user. R4. t is 17 m 3404583 OLOOL40 OTL m 870-5-1 IEC O11 o 1 o o 11 6.2.4.2.3 Frame format of single control characters Two single characters are specified. 11 1 Control Character I : 00100010111 - Bit sequence online- 1 2 3 4 5 6 7 8 9 10 11 Start character 1: O O 1 O O 1 1 1 Control character /I : Bit sequence online- 1 2 3 4 5 6 7 8 9 10 11 The single control characters may be used for the transmission of particular control information, such as for exampl
