1、STD-BSI BS EN L31bZ-Z-ENLL 1777 IpB LL24bb9 07555U2 BU9 e BRITISH STANDARD Maritime navigation and radiocommunication equipment and systems - Digital interfaces - Part 2: Single talker and multiple listeners, high-speed transmission - BS EN 61 162-2:1999 IEC 61 162-2: 1998 The European Standard EN 6
2、1162-21998 has the status of a British Standard ICs 47.020.70 u- NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGIPT LAW STD-BSI BS EN bLLb2-2-ENGL 1999 Lb2qbbS 0755503 745 Amd. No. BS EN 61162-21999 Date Text affected National foreword This British Standard is the English language v
3、ersion of EN 61162-21998. It is identical with IEC 61162-21998. The UK participation in its preparation was entnisted to Technical Committee EPMO, Marine naviagation and radiocommunication equipment and systems, which has the responsibility to: - aid enquirers to undersand the text; - present to the
4、 responsible internationalEuropean committee any enquiries on the interpretation, or proposaJs for change, and keep the UK interests informed; - monitor related international and European developments and promulgate them in the UK. A list of organizations represented on this committee can be obtaine
5、d on request to its secretary. Rom 1 January 1997, all IEC publications have the number 60000 added to the old number. For instance, IEC 27-1 has been renumbered as IEC 60027-1. For a period of time during the change over fkom one numbering system to the other, publications may contain identifiers f
6、rom both systems. Cross-references Attention is drawn to the fact that CEN and CENELEC Standards normally include an annex which lists nonnative references to international publications with their corresponding European publications. The British Standards which implement these international or Europ
7、ean publications may be found in the BSI Standards Catalogue under the section entitled International Standards Correspondence Index, or by using the fi b) the output drive capability as a talker; c) a list of approved sentences, noting unused fields, proprietary sentences transmitted as a talker, d
8、ata latency and transmission interval for each sentence; d) the load requirements as a listener; e) a list of sentences and associated data fields that are required by, or are acceptable to, a listener; f) the current software and hardware revision if this is relevant to the interface; g) an electri
9、cal description or schematic of the listenedtalker inputloutput circuits citing actual components and devices used, including connector type and part number; h) the version number and date of update of the standard for which compliance is sought. 2.2 Additional information As latency, filtering, err
10、or handling and data transmission interval can have a serious influence on the performance of a system, the manufacturer shall give careful consideration to these aspects. Documentation should include such data where applicable. 3 Hardware specification One talker and multiple listeners may be conne
11、cted in parallel over interconnecting wires. Because of EMC requirements shielded cables are recommended. The number of listeners depends on the output capability, the input drive requirements of the connected devices, and on the use of termination resistors. 3.1 Interconnecting wires Interconnectio
12、n between devices may be by means of a shielded two-conductor twisted-pair wire (A, 8) plus any means to secure common signal ground potential (C) for transmitting and receiving devices. For this purpose, a third wire additional to the twisted pair or the inner shield of double-shielded cable with i
13、nsulated shields may be used. STD-BSI - BS EN bLLb2-2-ENGL 1999 E lbZYbb9 0755509 3ib3 E Page 6 EN 61162-2:1998 3.2 Conductor definitions The conductors referred to in this standard are the signal lines A, B, C (common) and shield. 3.3 Electrical connection/shield requirements All signal and common
14、line connections A, B and C are connected in parallel. With single-shielded cables and a separate wire as common line C (signal ground), the shield shall be connected to the talker chassis and shall not be connected to any listener. However, the shield shall be continuous (unbroken) between all list
15、eners (see figure 1 and figure 2a). With double-shielded cables and the inner shield used as common line C (signal ground), the outer shield shall be connected to the talker chassis and shall not be connected to any listener. However, the outer shield shall be continuous (unbroken) between ali liste
16、ners (see figure 1 and figure 2b). With double-shielded cables and a separate wire as common line C (signal ground), the inner shield shall be connected to the talker chassis and shall not be connected to any listener. However, the inner shield shall be continuous (unbroken) between all listeners. T
17、he outer shield may be connected to the chassis on either side if required (see figure 1 and figure 2c). The cabling shall be designed in a way that stubs are avoided or kept as short as possible. if long cables are necessary, termination at the end of the line according to ITU-T V.ll shall be cons
18、ide red. 3.4 Connector No standard connector is specified. Wherever possible readily available commercial connectors shall be used. Manufacturers shall provide means for user identification of the connections used. 3.5 Electrical signal characteristics This subclause describes the electrical charact
19、eristics of transmitters and receivers. 3.5.1 Signal state definitions The idle, marking, logical 1, OFF or stop bit state is defined by a negative voltage on line A with respect to line B, as in IEC 61 162-1. The active, spacing, logical O, ON or start bit state is defined by a positive voltage on
20、line A with respect to line 6, as in IEC 61 162-1. 3.5.2 Talker drive circuits No provision is made for more than a single talker to be connected to the bus. The drive circuit shall meet, as a minimum, the requirements of ITU-T V.11. Improved and compatible driver circuits (e.g. EIA-485) used in a c
21、ompliant way are allowed. 3.5.3 Listener receive circuits Multiple listeners may be connected to a single talker. The listeners receive circuit shall comply with ITU-T V.11. Optional termination resistors for the line shall be provided. The input terminals A, B and C shall be electrically isolated f
22、rom the remaining electronics of the listening device. Reference is made to 3.5.4 and a sample circuit shown in figure 1 of this standard. STD-BSI BS EN b11b2-2-ENGL 1997 Lb24bb9 0755510 985 W Page 7 EN 61162-2:1998 3.5.4 Electrical isolation Within a listener there shall be no direct electrical con
23、nection between the signal lines A and 6, the signal ground C or the shield to ships mains ground or power line. This isolation shall be in accordance with IEC 60945. 3.5.5 Maximum voltage on the bus The maximum applied voltage between signal lines A and B and between either line and ground C shall
24、be in accordance with ITU-T V.ll. For protection against miswiring and for unintended connection to earlier TALKER designs, all receive circuit devices shall be capable of withstanding 15 V between either lines and signal ground for an indefinite period. 4 Data transmission Data is transmitted in se
25、rial asynchronous form in accordance with 1.2. The first bit is a start bit and is followed by data bits, least-significant-bit first as in figure 3. The following parameters are used: - baud rate 38 400 (bitsk); - data bits 8 (D7 = O), parity none; - Stop bits 1. 5 Data format protocol 5.1 Characte
26、rs All transmitted data shall be interpreted as ASCII characters. The most significant bit of the eight-bit character shall always be transmitted as zero (D7 = O). 5.1.1 Reserved characters The resewed character set consists of those ASCII characters shown in 6.1 (table 1) of IEC 61162-1. These char
27、acters are used for specific formatting purposes, such as sentence and field delimiting, and shall not be used in data fields. 5.1.2 Valid characters The valid character set consists of all printable ASCII characters (HEX 20 to HEX 7E) except those defined as reserved characters. The list of the val
28、id character set is given in 6.1 (table 2) of IEC 61 162-1. 5.1.3 Undefined characters ASCII values not specified as either reserved characters or valid characters are excluded and shall not be transmitted at any time. 5.1.4 Character symbols When individual characters are used in this standard to d
29、efine units of measurement, to indicate the type of data field, type of sentence, etc., they shall be interpreted according to the character symbol in 6.1 (table 3) of IEC 61 162-1. STD-BSI BS EN bLLb2-2-ENGL 1979 1b24bb7 0755511 ALL Page 8 EN 61162-2:1998 5.2 Fields A field consists of a string of
30、valid characters, or no characters (null field), located between two appropriate delimiter characters. 5.2.1 Address field An address field is the first field in a sentence and follows the “$“ delimiter; it serves to define the sentence. Characters within the address field are limited to digits and
31、upper-case letters. The address field shall not be a null field. Only sentences with the following three types of address fields shall be transmitted. 5.2.1.1 Approved address field Approved address fields consist of five characters defined by this standard. The first two characters are the talker i
32、dentifier, listed in 6.2 (table 4) of IEC 61162-1. The next three characters form the sentence formatter used to define the format and the type of data. A list of approved sentence formatters is given in 6.2 (table 5) of IEC 61 162-1. 5.2.1.2 Query address field The query address field consists of f
33、ive characters and is used for the purpose of requesting transmission of a specific sentence on a separate bus from an identified talker. 5.2.1.3 Proprietary address field The proprietary address field consists of the proprietary character P followed by a three- character manufacturers mnemonic code
34、, used to identify the talker issuing a proprietary sentence, and any additional characters as required. A list of valid manufacturers mnemonic codes may be obtained from NMEA. 5.2.2 Data fields Data fields in approved sentences follow a ,* delimiter and contain valid characters in accordance with t
35、he formats illustrated in 6.2 (table 6) of IEC 61162-1. Data fields in proprietary sentences contain only valid characters but are not defined by this standard. Because of the presence of variable data fields and null fields, specific data fields shall only be located within a sentence by observing
36、the field delimiters ,“. Therefore, it is essential for the listener to locate fields by counting delimiters rather than counting the total number of characters received from the start of the sentence. 5.2.2.1 Variable length fields Although some data fields are defined to have fixed length, many ar
37、e of variable length in order to allow devices to convey information and to provide data with more or less precision, according to the capability or requirements of a particular device. Variable length fields may be alpha-numeric or numeric fields. Variable numeric fields may contain a decimal point
38、 and may contain leading or trailing zeros. 5.2.2.2 Data field types Data fields may be alpha, numeric, alphanumeric, variable length, fixed length, fixedvariable (with a portion fixed in length while the remainder varies). Some fields are constant, with their value dictated by a specific sentence d
39、efinition. The allowable field types are summarized in 6.2 (table 6) of IEC 61 162-1. Page 9 EN 61162-2:1998 5.2.2.3 Null fields A null field is a field of length zero, .e. no characters are transmitted in the field. Null fields shall be used when the value is unreliable or not available. For exampl
40、e, if heading information were not available, sending data of “000“ is misleading because a user cannot distinguish between “000“ meaning no data and a legitimate heading of “000“. However, a null field, with no characters at all, clearly indicates that no data is being transmitted. Null fields with
41、 their delimiters can have the following appearance depending on where they are located in the sentence: The ASCII NULL character (HEX 00) shall not be used as the null field. 5.2.3 Checksum field A checksum field shall be transmitted in any sentence. The checksum field is the last field in a senten
42、ce and follows the checksum delimiter character “*“. The checksum is the eight-bit exclusive OR (no start or stop bits) of all characters in the sentence, including I,“ delimiters, between but not including the “$I and the “* delimiters. The hexadecimal value of the most significant and least signif
43、icant four bits of the result is converted to two ASCII characters (0-9, A-F) for transmission. The most significant character is transmitted first. Examples of the checksum field are: $GPGLL,5057.970,N100146.1 10,E,142451 ,A*27 and $GPVTG1089.0,T, 15.2,N,*7F. 5.3 Sentences This subclause describes
44、the general structure of sentences. Details of specific sentence formats are found in 6.3 of IEC 61162-1. Some sentences may specify restrictions beyond the general limitations given in this part of this standard. Such restrictions may include defining some fields as fixed length, numeric or text on
45、ly, required to be non-null, transmitted with a certain frequency, etc. The maximum number of characters in a sentence shall be 82, consisting of a maximum of 79 characters between the starting delimiter “$“ and the terminating delimiter . The minimum number of fields in a sentence is one (1). The f
46、irst field shall be an address field containing the identity of the talker and the sentence formatter which specifies the number of data fields in the sentence, the type of data they contain and the order in which the data fields are transmitted. The remaining portion of the sentence may contain zer
47、o or multiple data fields. The maximum number of fields allowed in a single sentence is limited only by the maximum sentence length of 82 characters. Null fields may be present in the sentence and shall always be used if data for that field is unavailable. All sentences begin with the sentence start
48、ing delimiter character “$I and end with the sentence terminating delimiter cLF. STD*BSI BS EN bLLb2-2-ENGL 1777 Lb2LibbS 0755513 b74 M Page 10 EN 61162-2:1998 5.3.1 Description of approved sentences Approved sentences are those designed for general use and detailed in this standard. Approved senten
49、ces are listed in 6.3 of IEC 61162-1 and shall be used wherever possible. Other sentences, not recommended for new designs, may be found in practice. Such sentences are listed in NMEA 0183. Information on such sentences may be obtained from NMEA (see 5.3.3). An approved sentence contains, in the order shown, the following elements: ASCII 3. HEX 24 “,“ “* OD OA Description - start of sentence - talker identifier and sentence formatter - zero or more data fields - checksum field - end of sentence 5.3.1.1 Approval sentence structure The following provides a summ
