BS/EN 61300-1-2016 pdf download.Fibre optic interconnecting devices and passive components Basic test and measurement procedures Part 1: General and guidance.
The expression of a quantity as a numerical value indicates the intention that the test should be carried out at the stated value. The object of stating tolerances is to take account of the following factors in particular:
• the difficulties in regulating some devices and their drift (undesired slow variation) during the test;
• uncertainties of instrument;
• non-uniformity of environmental parameters, for which no specific tolerances are given, in the test space in which the OUTs are located.
These tolerances are not intended to allow latitude in the adjustment of the values of the parameter within the test space. Hence, when a quantity is expressed by a nominal value with a tolerance, the test apparatus shall be adjusted so as to obtain this nominal value making allowance for the uncertainties of instrument.
In principle, the test apparatus shall not be adjusted to maintain a limiting value of the tolerance zone, even if its uncertainty is so small as to ensure that this limiting value would not be exceeded.
EXAMPLE: if the quantity is expressed numerically as 100 ± . the test apparatus is adjusted to maintain the
target value of 100 making allowance for the uncertainties of instrument and in no case is adjusted to maintain a
target value of 95 or 105.
In order to avoid any limiting value applicable to the OUT during the carrying out of the test, it may be necessary in some cases to set the test apparatus near to one tolerance limit.
In the particular case where the quantity is expressed by a nominal value with a unilateral tolerance (which is generally the case unless justified otherwise by special conditions, for example, a non-linear response), the test apparatus shall be set as close as possible to the nominal value (which is also a tolerance limit) taking account of the uncertainty of measurement, which depends on the apparatus used for the test (including the instruments used to measure the values of the parameters).
+0
EXAUPLE If the quantity is expressed numerically as 100 % % and the test apparatus is capable of an
overall uncertainty in the control of the parameter of ±1 %. then the test apparatus Is adjusted to maintain a target
value of 99 %. If, on the other hand, the overall uncertainly is ± 2,5%, then the adjustment is set to maintain a
target value of 97.5 %.
6.3 Quantity expressed as a range of values Examples of forms of presentation:
a) From 18 “C to 28 “C
Relative humidity from 80 % to 100 %
From 1 h to 2 h
b) Return loss 55 dB Attenuation ≤ 0.50 dB
The use of words in expressing a range leads to ambiguity: for example, the phrase “from
80 % to 100 %“ is recognised as “excluding the values of 80 and 100” by some readers, as
“80 and 100 are Included” by others. The use of symbols, for example > 80 or 80, is
generally less likely to be ambiguous and is therefore to be preferred.
The expression of a quantity as a range of values indicates that the value to which the test apparatus is adjusted has only a small influence on the result of the test.
Where the uncertainty of the control of the parameter (including uncertainties of instrument) permits, any desired value within the given range may be chosen. For example, if it is stated that the temperature shall be from 18 ‘C to 28 °C, any value within this range can be used (but it is not intended that the temperature should be programmed to vary over the range).
7 Graphical symbols and terminology
The terminology used in the interpretation and preparation of fibre optic test and measurement procedures shall be taken from IEC 60050-731.
Graphical symbols used for the preparation and interpretation of fibre optic test and measurement procedures shall be selected where possible from IEC 60617.BS/EN 61300-1-2016 pdf download.
BS/EN 61300-1-2016 pdf download
PS:Thank you for your support!
