1、BSI Standards PublicationBS ISO 19235:2015Analogue quartz clocks Timing accuracyBS ISO 19235:2015 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of ISO 19235:2015.The UK participation in its preparation was entrusted to TechnicalCommittee STI/53, Specifications and t
2、est methods for jewellery andhorology.A list of organizations represented on this committee can beobtained on request to its secretary.This publication does not purport to include all the necessaryprovisions of a contract. Users are responsible for its correctapplication. The British Standards Insti
3、tution 2015.Published by BSI Standards Limited 2015ISBN 978 0 580 83469 1ICS 39.040.20Compliance with a British Standard cannot confer immunity fromlegal obligations.This British Standard was published under the authority of theStandards Policy and Strategy Committee on 31 October 2015.Amendments/co
4、rrigenda issued since publicationDate T e x t a f f e c t e dBS ISO 19235:2015 ISO 2015Analogue quartz clocks Timing accuracyHorloges analogiques quartz Prcision du tempsINTERNATIONAL STANDARDISO19235First edition2015-10-15Reference numberISO 19235:2015(E)BS ISO 19235:2015ISO 19235:2015(E)ii ISO 201
5、5 All rights reservedCOPYRIGHT PROTECTED DOCUMENT ISO 2015, Published in SwitzerlandAll rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on the in
6、ternet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below or ISOs member body in the country of the requester.ISO copyright officeCh. de Blandonnet 8 CP 401CH-1214 Vernier, Geneva, SwitzerlandTel. +41 22 749 01 11Fax +41 22 749 09 47cop
7、yrightiso.orgwww.iso.orgBS ISO 19235:2015ISO 19235:2015(E)Foreword ivIntroduction v1 Scope . 12 Terms and definitions . 13 Basic parameters and requirements of timing accuracy 13.1 Mean instantaneous rate . 13.2 Voltage coefficient, CU13.3 Temperature coefficient, Ct.24 Test methods . 24.1 Test cond
8、itions 24.1.1 Test environment 24.1.2 Power supply . 24.1.3 Pre-running 24.2 Test apparatus . 24.3 Testing 24.3.1 Mean instantaneous rate 24.3.2 Voltage coefficient, CU.34.3.3 Temperature coefficient, Ct3Annex A (informative) Main factors affecting the timing accuracy. 5Annex B (informative) Timing
9、accuracy expressions of quartz clocks . 6Bibliography 7 ISO 2015 All rights reserved iiiContents PageBS ISO 19235:2015ISO 19235:2015(E)ForewordISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing In
10、ternational Standards is normally carried out through ISO 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 organizations, governmental and non-governmental, in liaison
11、with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.The procedures used to develop this document and those intended for its further maintenance are described in the ISO/IEC Directiv
12、es, Part 1. In particular the different approval criteria needed for the different types of ISO documents should be noted. This document was drafted in accordance with the editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).Attention is drawn to the possibility that some o
13、f the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of any patent rights identified during the development of the document will be in the Introduction and/or on the ISO list of patent declaratio
14、ns received (see www.iso.org/patents).Any trade name used in this document is information given for the convenience of users and does not constitute an endorsement.For an explanation on the meaning of ISO specific terms and expressions related to conformity assessment, as well as information about I
15、SOs adherence to the WTO principles in the Technical Barriers to Trade (TBT) see the following URL: Foreword - Supplementary informationThe committee responsible for this document is ISO/TC 114, Horology, Subcommittee SC 14, Table and wall clocks.iv ISO 2015 All rights reservedBS ISO 19235:2015ISO 1
16、9235:2015(E)IntroductionEach year, there is a large number of analogue quartz clocks produced and this International Standard aims to provide quality information for consumers and producers. This International Standard will help producers by giving them quality control methods and customers by infor
17、ming them about expectations they could have on those products. ISO 2015 All rights reserved vBS ISO 19235:2015BS ISO 19235:2015Analogue quartz clocks Timing accuracy1 ScopeThis International Standard specifies the basic parameters, requirements, and testing methods of timing accuracy for analogue q
18、uartz clocks, hereinafter referred to as “the quartz clock”.This International Standard applies to analogue quartz table and wall clocks which the oscillator frequency is 32 768 Hz and the nominal voltage is DC 1,5 V. Analogue quartz clock movements can refer to it.This International Standard does n
19、ot apply to the following quartz clocks: clocks for particular applications such as clocks used in aircraft, ship, vehicle, and facilities; clocks incorporated into other products; clocks in which time is radio-synchronized.2 Terms and definitionsFor the purposes of this document, the following term
20、s and definitions apply.2.1mean instantaneous ratemarithmetic mean value of three instantaneous rates of the quartz clock separately measured on three successive days, in “s/d” or “s/m”2.2voltage coefficientCUvariation rate of instantaneous rate of the quartz clock caused by the variation of source
21、voltage2.3temperature coefficientCtvariation rate of instantaneous rate of the quartz clock caused by the variation of temperature2.4nominal voltageUnvoltage for which the movement is destined3 Basic parameters and requirements of timing accuracy3.1 Mean instantaneous rate, m After the quartz clock
22、has been continuously running for 3 d, the mean instantaneous rate shall be within 1,0 s/d to +1,0 s/d.3.2 Voltage coefficient, CUThe voltage coefficient, CU, shall be within 1,0 s/(dV) to +1,0 s/(dV).INTERNATIONAL STANDARD ISO 19235:2015(E) ISO 2015 All rights reserved 1BS ISO 19235:2015ISO 19235:2
23、015(E)3.3 Temperature coefficient, CtThe temperature coefficient, Ct1, shall be within 0 s/(dC) to +0,1 s/(dC) and Ct2shall be within 0,1 s/(dC) to 0 s/(dC).4 Test methods4.1 Test conditions4.1.1 Test environmentThe test ambient temperature shall be 18 C to 25 C, the temperature variation shall be w
24、ithin 2 C during the whole test and the relative humidity shall be between 50 % and 70 %.4.1.2 Power supplyUnless otherwise specified, the test power supply during the test shall be the nominal voltage of the quartz clock of DC 1,5 V.4.1.3 Pre-runningBefore the test, the quartz clock shall run for a
25、t least 2 h in the test environment specified in 4.1.1.4.2 Test apparatusThe resolution and maximum permissible error of the test apparatus can refer to Table 1.Table 1 Test apparatusTest apparatus Resolution Maximum permissible errorInstantaneous rate test instrument 0,01 s/d 0,03 s/dTemperature an
26、d humidity cabinet 1 C, RH 1 % 1 C, RH 5 %Constant voltage power supply 0,01 V 0,5 %4.3 Testing4.3.1 Mean instantaneous rate, mThe quartz clock shall be placed at a temperature of (23 1) C for at least 2 h. Then the instantaneous rates m1, m2, m3for the first, second and third day shall be measured
27、respectively and the mean instantaneous rate m calculated in accordance with Formula (1):mmmm=+1233(1)wheremis the mean instantaneous rate for 3 d;m1is the instantaneous rate of the first day;m2is the instantaneous rate of the second day;2 ISO 2015 All rights reservedBS ISO 19235:2015ISO 19235:2015(
28、E)m3is the instantaneous rate of the third day.4.3.2 Voltage coefficient, CUThe instantaneous rate variation of the quartz clock caused by 1 V voltage variation is called the voltage coefficient, CU, when the supply voltage of the quartz clock is reduced from 100 % Unto 90 % Un.The instantaneous rat
29、es of the quartz clock m1,50and m1,35shall be measured respectively under the supply voltage of DC 1,50 V and DC 1,35 V, when Unis 1,50 V, and CUis calculated in accordance with Formula (2):CmmU=150135150135,(2)whereCUis the voltage coefficient, in s/(dV);m150,is the instantaneous rate under the vol
30、tage of DC 1,50 V (100 %), in s/d;m135,is the instantaneous rate under the voltage of DC 1,35 V (90 % Un), in s/d.4.3.3 Temperature coefficient, CtThe variation of instantaneous rate caused by 1 C temperature variation is called temperature coefficient, Ct1, when the temperature is decreased from 23
31、 C to 8 C. The variation of instantaneous rate caused by 1 C temperature variation is called temperature coefficient, Ct2, when the temperature is increased from 23 C to 38 C.The quartz clock shall be placed at a temperature of 23 C 1 C for at least 2 h, then the instantaneous rate, m23, shall be me
32、asured. Afterwards, it shall be placed at a temperature of 8 C 1 C for at least 2 h, then the instantaneous rate, m8, shall be measured. After the test, it shall be placed for 1 h in the environment described in 4.1.1 and then placed at a temperature of 38 C 1 C for at least 2 h. Afterwards, the ins
33、tantaneous rate, m38, shall be measured. Ct1and Ct2are calculated in accordance with Formula (3) and Formula (4), respectively:Cmmt123 823 8=(3)whereCt1is the temperature coefficient when the temperature is decreased from 23 C to 8 C, in s/(dC);m23is the instantaneous rate at 23 C, in s/d;m8is the i
34、nstantaneous rate at 8 C, in s/d.Cmmt238 2338 23=(4)whereCt2is the temperature coefficient when the temperature is increased from 23 C to 38 C, in s/(dC); ISO 2015 All rights reserved 3BS ISO 19235:2015ISO 19235:2015(E)m23is the instantaneous rate at 23 C, in s/d;m38is the instantaneous rate at 38 C
35、, in s/d.4 ISO 2015 All rights reservedBS ISO 19235:2015ISO 19235:2015(E)Annex A (informative) Main factors affecting the timing accuracyA.1 GeneralThe main factors affecting the timing accuracy of the quartz clocks are temperature and ageing.A.2 TemperatureThe quartz crystal frequency and the load
36、capacitance value inside the oscillation circuit of the quartz clock change along with the temperature. This change will have impact on the timing accuracy of the quartz clock. The timing accuracy of the quartz clock at the low or high temperature is different from the timing accuracy at the test en
37、vironment temperature of (23 1) C. The instantaneous rate shall be within 2,0 s/d to +1,0 s/d in the temperature range of 8 C to 38 C.A.3 AgeingThe main ageing factors for quartz clock include the following: ageing of the quartz; ageing of the load capacitance inside the oscillation circuit; decreas
38、e of the vacuum encapsulation of quartz.The ageing factors will have certain impacts on timing accuracy of the quartz clock. Usually, after the quartz clock has been used in normal condition (10 C to 35 C, RH 70 %) for 1 y, it may cause 0,2 s/d variation in mean instantaneous rate. Consumers should
39、be aware of this ageing impact on timing accuracy after the quartz clock has been regularly used over 1 y. ISO 2015 All rights reserved 5BS ISO 19235:2015ISO 19235:2015(E)Annex B (informative) Timing accuracy expressions of quartz clocksB.1 GeneralExpressions of timing accuracy of the quartz clock d
40、iffer in different countries or regions. Thre are three expressions as follows: instantaneous daily rate; instantaneous monthly rate; average monthly rate.B.2 Instantaneous daily rateTest the timing accuracy of the quartz clock within a short time and convert it into a daily rate called instantaneou
41、s daily rate, in s/d.B.3 Instantaneous monthly rateTest the timing accuracy of the quartz clock within a short time and convert it into a monthly rate called instantaneous monthly rate, in s/m.B.4 Relationship between instantaneous daily rate and instantaneous monthly rateInstantaneous monthly rate
42、= Instantaneous daily rate 30NOTE The monthly rate assumes there are 30 days in a month.B.5 Average monthly rateThe value that was calculated monthly rate from the cumulative total of probable rate of 1 y. Method of simulation of probable rate is different by each of the countries and regions.6 ISO
43、2015 All rights reservedBS ISO 19235:2015ISO 19235:2015(E)BibliographyISO 6426-2, Horological vocabulary Part 2: Technical and commercial definitions ISO 2015 All rights reserved 7BS ISO 19235:2015ISO 19235:2015(E) ISO 2015 All rights reservedICS 39.040.20Price based on 7 pagesThis page deliberately
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