《ISO-8728-1997.pdf》由会员分享，可在线阅读，更多相关《ISO-8728-1997.pdf（16页珍藏版）》请在三一文库上搜索。
1、INTERNATIONAL STANDARD IS0 8728 Second edition 1997-06- 15 Ships and marine technology - Marine gyro-compasses Navires et technoiogie maritime - Compas gyroscopiques B usage marin Reference number IS0 8728: 1997(E) Copyright International Organization for Standardization Provided by IHS under licens
2、e with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/21/2007 02:50:11 MDTNo reproduction or networking permitted without license from IHS -,-,- IS0 8728: 1997(E) Foreword IS0 (the International Organization for Standardization) is a worldwide federation of national standards
3、bodies (IS0 member bodies). The work of preparing International Standards is normally carried out through IS0 technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizat
4、ions, governmental and non-governmental, in liaison with ISO, also take part in the work. IS0 collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. Draft International Standards adopted by the technical committees are circul
5、ated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. International Standard IS0 8728 was prepared by Technical Committee lSO/TC 8, Ships and marine technology, Subcommittee SC 6, Navigation. This second
6、 edition cancels and replaces the first edition (IS0 8728:1987), which has been technically revised. Annex A forms an integral part of this International Standard. Annex B is for information only. 0 IS0 1997 All rights reserved. Unless otherwise specified, no par? of this publication may be reproduc
7、ed or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from the publisher. International Organization for Standardization Case postale 56 l CH-1211 Geneve 20 l Switzerland Internet central iso.ch x.400 c=ch; a=400net;
8、 p=iso; o=isocs; s=central Printed in Switzerland ii Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/21/2007 02:50:11 MDTNo reproduction or networking permitted without license from IHS
9、-,-,- INTERNATIONAL STANDARD IS0 IS0 8728:1997(E) Ships and marine technology - Marine gyro-compasses 1 Scope This International Standard specifies the construction, performance and type testing for gyro-compasses required by Chapter V of SOLAS, 1974. 2 Normative references The following standards c
10、ontain 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 International Standard are encouraged to invest
11、igate the possibility of applying the most recent editions of the standards indicated below. Members of IEC and IS0 maintain registers of currently valid International Standards. ISO/R 694: 1968, Positioning of magnetic compasses in ships. IEC 9451994, Marine navigational equipment - Genera/ require
12、ments - Methods of testing and required test results. International Convention on Safety of Life at Sea (SOLAS) 1974 (amended). 3 Definitions For the purposes of this International Standard, the following definitions apply. 3.1 gyro-compass: Complete equipment including all essential elements of the
13、 complete design. 3.2 true heading: Horizontal angle between the vertical plane passing through the true meridian and the vertical plane passing through the ships fore-and-aft datum line; it is measured from true north (000”) clockwise through 360. NOTE - When the gyro-compass equipment is not insta
14、lled on board ship, this “true heading” is regarded as the true heading of the lubber line. Where a gyro-compass has the facility of introducing a correction by moving the lubber line, the correction is set for the local latitude. 3.3 settled: Stable situation when any three readings taken at interv
15、als of 30 min are within a band of 0,7”, with the compass level and stationary. NOTE - The settling time is the elapsed time between the time of switch-on at the initial heading error and the third recording of the settle. 3.4 settle point heading: Mean value of ten readings taken at 20 min interval
16、s after the compass has settled as defined in 3.3. 1 Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/21/2007 02:50:11 MDTNo reproduction or networking permitted without license from IHS
17、-,-,- IS0 8728:1997( E) IS0 3.5 3.6 settle point error: Difference between the settle point heading as defined in 3.4 and the true heading. error: Difference between the observed value and the settle point heading as defined in 3.4. 3.7 bearing repeater compass: Device that reproduces the master com
18、pass card at a remote location. 3.8 compass card: Graduated dial of the compass which indicates the measured direction of the meridian. 39 upon latitude error: Error to which the local latitude. some gyro-compasses are subject 9 the magnitude and sign of which depend NOTE - Means are provided for co
19、rrecting this error. 3.10 speed error: Error to which gyro-compasses are subject, the magnitude and sign of which depend upon the speed, course and latitude of the ship. NOTE - Means are provided for correcting this error. 3.11 lubber line: Index line situated on the body of a compass against which
20、the compass heading is read. 3.12 master compass: Main compass unit which supplies the heading information to the repeaters and other navigational aids. 3.13 Scorsby table: Test machine which independently oscillates a platform about three axes; it is used to simulate the motion of a ship. 4 Constru
21、ction Gyro-compass units shall conform to the following requirements. 4.1 The equipment shall be capable of continuous operation under conditions of vibration, humidity, change of temperature and variations of the power supply as specified in 6.10.1 to 6.105 4.2 For follows. those ships are required
22、 to carry bearing repeater compasses, the con struction of shall be as a) The bearing repeater compass shall be designed to be fitted with an azimuth reading device. b) A gimbal mechanism shall be provided to enable the bearing repeater compass card to be held horizontally against the ships motion c
23、) Any bearing repeater compass intended for use on an open deck shall be waterproof. 4.3 The compass card shall be graduated at equal intervals of 1 O or fraction thereof. The graduation error shall be less than + 0,2”. A numerical indication shall be provided at least at every IO”, starting from OO
24、OO clockwise through 360. 4.4 Fully adequate illumination shall be provided to enable the reading of all compass cards at all times. Facilities for dimming shall be provided. 4.5 Both master compass and repeater compasses shall be provided with a lubber line to indicate the ships heading. 4.5.1 The
25、base or some other fixed extremity of the compass shall be marked or identified in such a way as to facilitate the installation of the compass in a ship SO that the lubber line lies in a vertical fore-and-aft plane of the ship. Where a gyro-compass has the facility of introducing a correction by mov
26、ing the lubber line, the correction during installation shall be set to zero. 2 Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/21/2007 02:50:11 MDTNo reproduction or networking permitte
27、d without license from IHS -,-,- IS0 IS0 8728:1997(E) If such marks or identifications are not in the same vertical plane as the uncorrected lubber line, then the horizontal angular relationship between them shall be clearly indicated. 4.6 Means shall be provided for correcting the errors induced by
28、 speed and latitude. Graphical or tabular means of correction may be used. 4.7 Steps shall be taken to eliminate as far as is practical the causes of, and to suppress, electromagnetic interference between the gyro-compass and other equipment on board. 4.8 Mechanical noise from all units shall be so
29、limited as to ensure the hearing of sounds on which the safety of the ship may depend. 4.9 The equipment shall be so constructed that it is readily accessible for maintenance purposes. 4.10 An automatic alarm shall be provided to indicate a power failure in the gyro-compass. 4.11 Means shall be inco
30、rporated for the protection of the equipment from excessive currents and voltages, transients and accidental reversal of power supply polarity. 4.12 The gyro-compass shall be designed to enable heading information to be provided to other navigational aids. 5 Performance requirements 5.1 Accuracy in
31、latitudes up to 60” 51.1 Settling time When switched on in accordance with the manufacturers instructions, the compass shall settle within 6 h. 5.1.2 Settle point error 5.1.2.1 The settle point error as defined in 3.5 at any heading shall not exceed * 0,75” x secant latitude, and the RMS value of th
32、e differences between individual heading indications and the mean value shall be less than 0,25” x secant latitude. 5.1.2.2 The repeatability of settle point error from one run-up to another shall be within 0,25O x secant latitude. 5.1.3 Settling time under operational conditions When switched on in
33、 accordance with the manufacturers instructions, the compass shall settle within 6 h when rolling and pitching with simple harmonic motion of any period between 6 s and 15 s, a maximum angle of 5”, and a maximum horizontal acceleration of 0,22 m/s? 5.1.4 Settle point error under general conditions T
34、he repeatability of the settle point error of the master compass shall be within + lo x secant latitude under the general conditions and including variations in magnetic fields likely to be experienced in the ship in which it is installed. 5.1.5 Residual error in correction The residual steady state
35、 error, after correction for speed and course influences at a speed of 20 knl), shall not exceed + 0,25” x secant latitude. 5.1.6 Effect of alteration of speed The error due to a rapid alteration of speed of 20 kn shall not exceed + 2O. 1) knots Copyright International Organization for Standardizati
36、on Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/21/2007 02:50:11 MDTNo reproduction or networking permitted without license from IHS -,-,- IS0 8728: 1997(E) IS0 5.1.7 Effect of alteration of course The error due to a rapid alteration of cou
37、rse of 180” at a speed of 20 kn shall not exceed + 3”. 5.1.8 Accuracy on a Scorsby table The transient and steady state errors due to rolling, pitching, and yawing, with simple harmonic motions of any period between 6 s and 15 s, maximum angles of 20”, IO” and 5” respectively, and a maximum horizont
38、al acceleration not exceeding 1 m/s? shall not exceed + 1 O x secant latitude. 5.1.9 Synchronization between the master compass and repeaters Once the repeaters have been synchronized with the master, the maximum divergence in reading between the master compass and repeaters under all operational co
39、nditions shall not exceed + 0,s”; for the purposes of this requirement, the latitude and speed correction shall be assumed equal to zero. 5.2 Other requirements Gyro-compasses shall be in accordance with the requirements of IEC 945:1994, clause 3. 6 Type tests 6.1 Construction The construction of th
40、e gyro-compass shall conform to the requirements specified in clause 4. 6.2 Settling time test The master compass shall be securely positioned on a nominally level and stationary base. It shall be energized from nominal value power supplies and started in accordance with the manufacturers instructio
41、ns from an initial heading error (high) of 30 or more. The settling time (see 3.3) shall meet the requirements of 5.1 .I. 6.3 Settle point error test When the master compass has settled as defined in 3.3, the settle point error (see 3.5) shall conform to the requirements specified in 5.1.2.1. 6.4 Se
42、ttle point heading repeatability test The master compass shall be started in accordance with the manufacturers instructions from an initial heading error (high) of 30” or more and shall be allowed to settle. The settle point heading shall be determined as specified in 3.4. The master compass shall t
43、hen be switched off for a period of not less than 12 h and not more than 7 days and then started again from an initial heading error (low) of 30 or more and the settle point heading measured again. The master compass shall then be switched off for a period of not less than 12 h and not more than 7 d
44、ays and then started again from an initial heading error (high) of 30 or more and the settle point heading determined. The three values of settle point heading so obtained shall be recorded and the difference between any two shall not exceed 0,25” x secant latitude. NOTE - If this test follows the t
45、est described in 6.3, then the “settle” obtained from that test may be used as the first value required by this repeatability test provided that the second “settle” follows a switch off period of not less than 12 h and not more than 7 days. 4 Copyright International Organization for Standardization
46、Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/21/2007 02:50:11 MDTNo reproduction or networking permitted without license from IHS -,-,- IS0 IS0 8728: 1997(E) 6.5 Settling time on a Scorsby table The master compass shall be mounted on a Scor
47、sby table with the master compass fore-and-aft line nominally parallel with one axis of the table which shall be designated the roll axis. The other nominally horizontal axis at right angles to the first shall be designated the pitch axis. The compass shall then be switched on in accordance with the
48、 manufacturers instructions with the following nominal simple harmonic table motions: - roll axis: Peak amplitude 5O + lo, period 15 s + 1 s; - pitch axis: Peak amplitude 5O +, 1 O, period 6 s + 1 s. The settling time measured between switch-on and compass settle as defined in 3.3 shall conform to t
49、he requirements specified in 5.1.3. NOTE - Compass readings to determine the settle condition may be taken with the level, and with a minimum delay before resuming the specified table motion. Scorsby table stationary and nominally 6.6 Scorsby test The master compass shall be settled on the Scorsby table with t