解读COSC证书(ZT)

An Overview of the COSC Certificate and Testing Procedures
By Michael Disher
Some History: Swiss Chronometer Testing and Certification
Chronometer testing in Switzerland took place at observatories in Neuchtel (1866 - 1975) and Geneva (1873 - 1967). Each observatory maintained its own testing standards. Generally speaking, the observatories did not test large numbers of movements meant for public sale. Typically, watches tested at the observatories were specially made and regulated pieces. A manufacturer might submit a few watches, then report the best results in advertising. The few watches that were actually tested were rarely sold to the public.

Testing of larger numbers of watches intended for public sale was conducted by official testing agencies. The testing agencies were originally called "Bureaux officiels de contrle de la marche des montres", abbreviated B.O. These agencies were founded between 1877 and 1956, and each operated independently of the others.

In 1973, the official testing agencies were placed under central administration and the name was changed to "Contrle Officiel Suisse des Chronomtres" , or COSC. The director of the COSC was located in La Chaux-de-Fonds, and offices were located in Le Locle, Bienne and Geneva.




Testing Procedures.
For a detailed discussion of COSC testing procedures, please see TZ Classic # 267 by Paul Schliesser.

By way of summary, watch manufacturers send batches of uncased movements (not watches) to the COSC for testing. The COSC charges manufacturers a fee for each movement tested. Movements are fitted with dial blanks and hands, and groups of movements are mounted on racks. The test lasts 15 days. During the test, the racks of movements are placed in five different positions and kept at three different temperatures. Results are tracked with cameras and lasers and reported to a computer. The passing movements receive a Bulletin de marche or watch rate certificate. These certificates are usually provided to the ultimate consumer with the watch, though some companies now charge an extra fee for the certificate.




Reading and Understanding the Modern COSC Certificate.
For purposes of this article, I am using an actual COSC certificate posted by MJ as TZ Classic # 55. To see the entire certificate (approximately 150K file) click here. For convenience, I am including the relevant portions of the certificate in this article. We will work our way from the top down. The top of the certificate appears below.


The COSC certificate states the results in French, German, Spanish and English. The certificate number appears in the upper left portion of the certificate. In the example above, this number is 5523048. Next to that on the right is the serial number of the movement tested. In the example, 102472.

Below the certificate and movement numbers, reading left to right, is a description of the movement by category, functions, diameter and thickness. In the example, the movement is Category I/1, referring to a spring balance oscillator movement that is more than 20 mm in diameter and which has a surface area greater than 314 square millimeters. This categorization scheme is explained on the back of the certificate (in French). The movement in question is an automatic chronograph, 30.00 millimeters in diameter and 7.55 millimeters thick.

The next section of the certificate - the center - shows certain of the raw test results, as shown below:


The second column shows the temperature in degrees Celsius at which the movement was being tested. Converting to Fahrenheit, 8 = 46.4, 23 = 73.4, and 38 = 100.4.

Column three shows the position in which the movement was tested. Vertical means the movement is hanging perpendicular to the ground, and horizontal means the movement is lying flat or is parallel with the ground. Dial up and down means the dial is horizontal and either above the movement or below the movement. The references to 3, 6 and 9 o'clock up in the vertical position mean the number 3, 6 or 9 is highest when looking at the dial straight on (or where 12 o'clock normally would be).

The next column shows the daily rates. The capital letter "M" with the small subscript numbers 1 - 15 represent the days of the test. The results in this column are not aggregate. In other words, the results are the gain or loss in seconds per day, without regard for the results of the previous day. In this column, we see the absolute gain or loss in seconds per day as measured against an accurate, consistent reference such as an atomic radio signal clock. For example, in the sample certificate shown above, the reading for M8 is -0.7. Reading across all the columns, that means that on Day 8 of the test, the watch was in the horizontal, dial down position at 23 degrees Celsius (73.4 F), and over 24 hours the rate was -0.7 seconds, or slow by 7/10 of a second compared with the reference.

The fifth and final column shows the difference between the first day measurement and the second day measurement in seconds per day. In the example above, M1 is -0.5 and M2 is -0.4, so the difference reported in column 5 is 0.1. M1 and M2 are used because they are two 24 hour testing periods under identical circumstances (position and temperature). Similarly, M3 is 1.9 and M4 is 2.8, so the difference reported in Column 5 is 0.9.

Just below the chart, on the right, is the date on which the COSC testing was completed. In the sample certificate, that date is July 25, 1997. If you're buying a watch that comes with a COSC certificate, you can compare the date testing ended with the present date to get an idea how long ago the test occurred. The test completion date won't necessarily tell you how old the watch is or how long its been in the dealer's case, however. As discussed below, manufacturers sometimes place movements in a vault upon return from the COSC, to be cased at a later date.

The important numbers are found at the bottom of the certificate, shown below. These are the Results or Summary. This is where the raw numbers are plugged into various formulae and the results of the testing are shown. Note that not all of the figures needed to make the final calculations appear in the center portion of the certificate. The Results or Summary reflect seven specific types of error deemed significant by the COSC. Each of the seven results must fall within COSC guidelines for the movement to pass. If even one result is outside the guidelines, the movement does not pass. Manufacturers are free to re-submit movements that fail.

The bottom section of our sample certificate is set forth below. A description of the tests and calculations follows.


1. Mean daily rate in the different positions. The first figure is mean daily rate in the different positions. This is the average rate over the first ten testing days. Simply add the rates for the first 10 days (in our example, the total is 18), then divide by 10 to get the result (1.8 in the example). To pass, the mean daily rate must be -4 to +6 seconds per day. COSC determines the mean daily rates by subtracting the time indicated by the movement 24 hours earlier from the time indicated on the day of observation. The -4 to +6 figures are the most often quoted when someone asks "what are the COSC guidelines". As we'll see, these two figures are only the tip of the iceberg.

The mean daily rate figure is said by some to be the most important to the owner of the watch. This "daily rate" tends to indicate how the watch will perform on the wrist in actual use. In his book "Wristwatch Chronometers", Fritz von Osterhausen states at page 59: "the lower the daily rate, the more accurate time a watch gives."

2. Mean Variation, or mean daily rate variation in 5 positions. This test is sometimes referred to as rate deviation. The COSC observes the movement's rate in the 5 positions each day over 10 days for a total of 50 rates. To pass, the mean variation in rates can be no more than 2 seconds per day. Generally speaking, this figure shows if a watch tends to run fast, slow or correct, or perhaps both fast and slow; in other words, the continuous rate of the movement. It is said this measurement shows the quality and reliability of a watch - a good quality watch will be consistent, whether it is fast, slow or correct. The disadvantage of a consistent error is that it accumulates. If the watch is 10 seconds fast every day, it will be over a minute fast at the end of a week. However, a watch that is consistent is more easily regulated, and so the error is more easily eliminated.

3. Maximum Variation. This is the largest difference between any two day's readings in a single position. In the sample certificate, we see that M9 (9th test day) was 1.3, and M10 (10th test day) was 4.3. On both of these days, the watch was in the horizontal position, and the difference was 3.0. This was the largest difference or variation between readings in any position. To pass, the greatest variation in any position cannot exceed 5 seconds.

4. Difference between flat and hanging positions. The figure is calculated by subtracting the average of the rates in the vertical position (first and second days) from the average of the rates in the horizontal position (ninth and tenth days). To pass, the difference must be no more than -6 to +8 seconds. Some experts feel this test shows the greatest difference between mass produced and hand adjusted movements. This figure tends to be lower for better quality movements.

5. Greatest difference between the mean daily rate and any individual rate. This is the largest difference between the mean daily rate (the figure reported in test number 1) and any individual rate during the first 10 days of positional testing. In our sample certificate, we see that on M6 (6th day of testing), the rate was 5.3. The mean daily rate was calculated at 1.8. The difference between these two is 3.5. The figure reported for test 5. To pass, the difference between the greatest daily rate and the mean daily rate can be no more than 10 seconds per day

6. Variation of Rate per 1 Centigrade. This is the temperature error of the movement, expressed in seconds per degree. The COSC subtracts the cold temperature rate (8 degrees) from the hot temperature rate (38 degrees) and divides by 30. In the sample certificate, the rate at 8 degrees was 7.1, and at 38 degrees it was -3.2. So -3.2 - 7.1 = -10.3 30 = -0.34. To pass, the variation cannot exceed 0.6 seconds per day.

7. Rate Resumption. This figure is obtained by subtracting the average mean daily rate of the first two days of testing from the mean daily rate of the last test day. To pass, the resumption of rate can be no more than 5 seconds.

By way of summary, the COSC passing guidelines for all seven tests for medium and large wristwatches (movements greater than 20 mm in diameter) are currently as follows:

1. a mean daily rate over 5 positions of a minimum of -4 seconds and a maximum of +6 seconds;
2. a mean variation between the days in each position of 2 seconds maximum;
3. a maximum variation between days in each position of 5 seconds;
4. a difference between horizontal and vertical positions of -6 seconds minimum and +8 seconds maximum;
5. a difference between mean daily rate and any individual rate of 10 seconds maximum;
6. a variation rate per degree centigrade or -0.6 seconds minimum to +0.6 seconds maximum
7. rate resumption of -5 seconds minimum to +5 seconds maximum.

The Value of the COSC Certificate to the Owner
The COSC certificate is not a precise indicator of how well a watch will perform on the owner's wrist. Rather, the test results show how well a given movement performed over a given period of time under certain conditions. Several factors can affect the actual performance the owner observes. First, The COSC test is only an artificial approximation of actual use. Second, the COSC does not test "watches" but only uncased movements. Following the test (assuming a movement passes), the movement returns to the manufacturer, where it is either cased or placed in a vault for casing at a later date. Movements can spend significant time in the vault. When they do, they are usually disassembled, cleaned, re-assembled, oiled and regulated, then cased. This can certainly affect the movement's performance, yet re-testing is not required.

Next, the watch may be affected by shipping in the distribution chain, where it might be exposed to shocks or extreme temperatures. Conditions at the dealer's shop also affect performance. If the watch sits unused for many months, if it sits under hot lights or in the window in the sun, if customers drop it while trying it on, this will affect how the watch performs on the owner's wrist.

Finally, the owner's personal habits can affect performance. Is the owner active or sedentary? Is the watch kept near full wind or allowed to run down? Is the watch in one position most of the time? Is the owner in cold or hot temperatures, or moving between the two? Is the watch placed on a winder? How is the winder set? Each of these also affects performance.

原文

[ 本帖最后由 小龙女 于 2006-6-20 09:10 编辑 ]

COSC认证的概述

By Michael Disher



翻译 TECO



历史：瑞士记时器测试及认证

记时器的测试是在瑞士 Neuchtel (1866 - 1975) 和 Geneva (1873 - 1967)进行的. 每个不同的测试机构有他们不同的测试标准。 一般来说，这些测试并不测试市面大量销售的机芯。主要是测试一些特制并调试过的样品，制造商可以将几块手表送测，并向外界宣布测试的最佳结果，这些样品是很少向外出售的。



为批量销售的手表所做的测试是在特定的官方测试机构完成的，这些机构一开始被称为"Bureaux officiels de contrle de la marche des montres", 简写 B.O. 这些机构成立于1877-1956间并互相独立。



1973年, 这些官方机构被集中管理并改名为 "Contrle Officiel Suisse des Chronomtres" , 即 COSC. COSC的中心机构位于La Chaux-de-Fonds, 而实验事分布于Le Locle, Bienne 和Geneva.



测试过程

关于COSC测试步骤的细节，请看Paul Schliesser所著的TZ Classic # 267



总的来说，厂商将批量的未装壳机芯（并非手表）送到COSC测试，COSC对每块测试的机芯收费。在这里，一组机芯被装上表盘和指针，安装在测试架上。机芯将在5个方位及3个不同温度下持续测试15天，通过测试的机芯将获得a Bulletin de marche 即 watch rate certificate. 该认证书经常被提供给最终用户，虽然有的厂商会收取额外费用。



读解现代COSC认证

为了解释，我使用了真实的 COSC 证书（by MJ as TZ Classic # 55）.如果想查看完整证书，click here. 为了方便,我只付上证书的部分内容。我们从头到脚好好看看，下面是证书的开头部分。

COSC证书使用了法语，德语，西班牙语和英语。认证号在证书左上脚，本例是5523048. 右边是所测试的机芯序列号，本例为102472.



在序列号之后，从左到右，是关于机芯类别，功能，直径和厚度的描述，该例中机芯为Category I/1, 是弹簧平衡动力机芯，直径大于20MM，表面积大于314平方毫米，该类型的机芯的结构配置在证书后面有法语解释，该机芯是自动上链码表机芯，直径30MM， 7.55 MM厚。



证书以下中心部分给出了原始测试结果，如下：

从左到右，第一列是测试天，表示测试的第1天到第15天。第二列标出测试摄氏温度，转换为华氏如下



8 = 46.4, 23 = 73.4, and 38 = 100.4.



第三列是机芯测试时的方位，垂直代表机芯被垂直于地面放置，水平代表平行地面放置。DIAL UP或 DIAL DOWN是表盘平行地面并位于机芯上方或者下方，3H，6H，9H表示将3，6，9点位于平常使用的12点指向之位置。



第四列给出日差，大写"M"和下标1 - 15 表示测试天，日差值并非合计，也就是说，表示的是每天的快慢秒数，并不考虑前一天的测试结果。这里我们看到的是每天相对与准确时间（原子钟）的误差。比如M8 是 -0.7秒，也就是说第8天，机芯位于水平位置，表盘向下，在23摄氏度（73。4F），24小时误差为-0.7秒。



第五列给出连续2天的日差值之间的差异，上例中，M1为-0.5，M2是 -0.4, 差异为0.1.之所以使用M1和 M2是因为这2天的测试环境相同，（方位和温度），同理，M3为.9M4是2.8,差异为0.9.



该表格以下右方是COSC测试完成日期， July 25, 1997.如果你购买到一块有COSC证书的手表，你可以比较一下，了解到测试是多久前进行的， 测试日期并不能准确告诉你这块表生产了多久，或在销售商的柜台上摆了多久，因为厂商有时会把做完COSC认证的机芯放入仓库，日后装壳。



在证书下部我们将发现将原始测试数据代入公式后得到的重要数据和结论。证书中间部分的所有的数值都经过计算，结果反映在7项被COSC认为非常重要的误差中，只有每一项指标都符合COSC的要求才能通过测试，如果测试失败，厂商可以修正后免费重新申请测试。



本例证书下部如图，我紧接着具体解释

1. 5方位日差平均值. 第1项数据是不同方位下的日差平均植，这是头10天测试误差的平均值。把头10天误差值求和( 本例为18秒/天，然后除10得到结果,本例为1.8秒/天)。要通过测试，平均日差必须在每天-4/天到 +6/天秒之间。COSC determines the mean daily rates by subtracting the time indicated by the movement 24 hours earlier from the time indicated on the day of observation.（晕，谁翻译一下,估计是笔者搞错了,应该是说日误差是用机芯24小时后的读值减去当天的原子钟标准记时得到的）. 当人们问起COSC要求是什么意思的时候，人们常用 -4 到 +6 秒这个数据回答，其实我们现在知道事实不仅仅是这么简单。平均日差通常一些人认为是最重要的数据， “日差”（我认为笔者指“平均日差”）反映出一块表在实际使用中的表现，在Fritz von Osterhausen的 "Wristwatch Chronometers"一书59页中说道“平均日差越低，表越准”

2.平均差, 或者说5方位的日差变化量的平均值. 这项测试有时候是指日差的方差值. COSC每天在5个不同方位观察机芯的误差,持续10天,得到50个误差值,然后计算其方差.要通过测试,日差的平均差必须在2秒/天以内. 总的说来, 这个数据表明了手表是越走越快,还是越走越慢,或者准确,又或者时快时慢;换句话说,是机芯的日差连续变化趋势, 听说这测试表明手表的质量和可靠性- 一块质量好的手表日差应该是稳定持续的,要么快,要么慢,要么准确. 日差持续的缺点是日差会积累,如果一块手表每天快10秒,那么一周就会快上几分钟. 不过,日茶稳定的手表更容易调校,结果是误差更容易被消除.

3. 最大差. 该数据是在某方位上2天之间日差值的最大差异,在例书中,我们可以看到M9 (第9天) 日差1.3秒/天, M10 (第10天) 是4.3秒/天. 这2天手表都是水平方位, 差异为3.0秒/天. 这就是在该测试中日差读值的最大差,(在任何方位的计算值中).要通过该测试,该值不能超过5秒/天.

4. 水平和立放位置的日差值差异, 该数据通过如下方法获得:用机芯水平方位日差的平均值(第9天和第10天)减去计算机芯垂直方位日差的平均值(第1天和第2天). 要通过测试,差异应该不超过-6 到+8 s/天.一些专家认为批量统芯和手工调校的机芯表现在这项测试中的区别最大.手工调校的机芯测试值更低.

5.平均日差和单日差的最大差异. 该数据反映测试一的数据和头10天里任意1天的日差测试数据的最大差值. 在本例中, 我们看到M6 (第6天), 的日差是5.3秒/天. 日差平均值是1.8秒/天, 2者差为3.5秒/天. 要通过测试,该值不能超过10秒/天.

6.温度每变化1摄氏度时的日差变化.这是机芯的温度误差,单位是秒/度(个人认为准确点是秒/日/度). COSC用最高温度30度减去最低温度8度,得到30度,然后用2温度下的日差区别除30. 在本例中,8度时的日差为7.1秒/天,38度的时候日差是-3.2秒/天.所以 -3.2 - 7.1 = -10.3/30 = -0.34. 要通过该测试,该值不能超过0.6 秒/天.

7.日差恢复. 该值是用最后一天的日差平均值减去头2天的日差平均值(不通,最后一天哪来的平均?估计是写烦了,出错.不过这个指标应该不太重要), 要通过测试,该值不得超过5秒/天.

总结一下COSC7项中,大型腕表测试指标 (机芯直径大于20 mm) 如下:

1. 5方位日差平均值最小-4S/天，最大+6S/天;

2. 5方位日差的平均差最大不超过2S/天;

3. 5方位中任意方位的日差最大差异不超过5S/天;

4. 水平和垂直放置的日差值差异最小-6S/天，最大+8S/天;

5. 平均日差和单日差的最大差异最大10S/天;

6. 温度每变化1摄氏度时的日差变化最小-0.6S/天/度，最大+6S/天/度;

7. 日差恢复最小-5S/天，最大+5S/天;

COSC认证对用户的价值

COSC证书并不能非常精确的表示手表在用户手上的表现.然而,测试结果表示了在特定环境下特定时间段内一个机芯能够取得怎样的表现.有几个因素可以影响用户的实际使用效果. 首先, COSC测试只是人工模拟大概的实际使用条件.其次,COSC只是测试机芯而并非手表.测试之后(假设机芯通过测试),机芯会被退回厂商,在那里它们也许被装配,也许被放入仓库日后装配.机芯也许会在仓库存放很长时间. 当它们被装配的时候,通常会被分解,清洁,重新组装并上油,调校,装壳.这可能会影响机芯的实际表现,而重新测试显然并不是必须的.

其次,手表也许会在运输和分销的过程中受影响,受到冲击和高温.销售商的环境条件也影响着手表的表现.如果手表几个月未使用,如果它在强烈日光下受热,如果用户在试戴的时候不小心跌落,这都会影响手表在用户手腕上的最终使用效果.

最后,用户的个人习惯也会影响性能.用户是喜欢运动还是经常安坐?手表是否经常保持满链? 手表是否经常保持在一个方位? 用户是经常呆在高温还是低温的地方? 也或许同时在两种地方行动?手表是否会被放在上链器上? 如果是,上链器是如何设置的? 上面提到的因素都会影响手表的最终表现.

[ 本帖最后由 小龙女 于 2006-6-20 09:25 编辑 ]

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My God!!太精深了，完全看不懂

虽然看不懂,但是很钦佩

辛苦了

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