IEC 61757:2018 pdf download

IEC 61757:2018 pdf download.Fibre optic sensors – Generic specification
1 Scope
This document is a generic specification covering optical fibres, components and sub- assemblies as they pertain specifically to fibre optic sensing applications. It has been designed to be used as a common working and discussion tool by the vendors of components and subassemblies intended to be integrated in fibre optic sensors, as well as by designers, manufacturers and users of fibre optic sensors independent of any application or installation. The objective of this document is to define, classify and provide the framework for specifying fibre optic sensors, and their specific components and subassemblies. The requirements of this document apply to all related fibre optic sensor standards which belong to IEC 61 757 (all parts). Standards of IEC 61 757 (all parts) contain requirements specific to sensors for particular quantities subject to measurement, and for a particular style or variant of such a fibre optic sensor.
3 Terms and definitions
For the purpose of this document, the terms and definitions given in IEC TR 61 931 , ISO/IEC Guide 99 (VIM), and the following apply. ISO and IEC maintain terminological databases for use in standardization at the following addresses: • IEC Electropedia: available at http://www.electropedia.org/ • ISO Online browsing platform: available at http://www.iso.org/obp 3.1 accuracy <of a fibre optic sensor> quality which characterizes the ability of a measuring instrument to provide an indicated value close to a true value of the measurand Note 1 to entry: This term is used in the “true value” approach. This is a value that would be obtained by a perfect measurement. Note 2 to entry: Accuracy is all the better when the indicated value is closer to the corresponding true value. 3.2 analogue signal interface signal interface which provides analogue output signals in a form directly usable for control or measurement purposes, and which is generally electrical Note 1 to entry: Output schemes should preferably comply with existing interface standards such as those existing for electrical analogue signals. Output schemes can be, for example, 4 mA to 20 mA, 0 mA to 20 mA, 0 V to 5 V, etc. A fibre optic sensor with a photodetector or other square-law detector, or with integrated signal processing electronics is a representative application example. 3.3 characteristic curve calibration curve expression of the relation between indication and corresponding measured quantity value Note 1 to entry: A characteristic curve/calibration curve expresses a one-to-one relation that does not supply a complete measurement result as it bears no information about the measurement uncertainty. [SOURCE: ISO/IEC Guide 99:2007, 4.31 , modified – The term “characteristic curve” has been added as a first preferred term, as well as in the note.] 3.4 communication interface digital interface of a fibre optic sensor which provides digital output signals in a form directly usable for control or measurement purposes, or which enables digital communication with other digital devices (e.g. personal computer) Note 1 to entry: It is usually designed to a specific standard (e.g. USB, RS-232) and used for transmitting control and measurement data. 3.5 distributed fibre optic sensor fibre optic sensor which provides a spatially resolved measurement of a measurand over an extended region by means of a continuous sensing element3.6 drift change in the metrological characteristics of a measuring instrument (and/or fibre optic sensor), generally slow, continuous, not necessarily in the same direction and not related to a change in the measurand 3.7 durability ability of a fibre optic sensor to perform a required function under defined conditions of use and maintenance, until a limiting state is reached Note 1 to entry: A limiting state of an item may be characterized by the end of the useful life, unsuitability for any economic or technological reasons or other relevant factors. 3.8 extrinsic fibre optic sensor fibre optic sensor in which the characteristics of the light are affected externally to the optical fibre(s) by the measurand