IEC 60746-1:2003 pdf – Expression of performance of electrochemical analyzers – Part 1: General
3.8 conventional true value value approximating to the true value of a quantity such that, for the purpose for which that value is used, the difference between the two will be regarded as negligible NOTE 1 Since the “true value” cannot be known exactly, for the sake of simplicity and where no ambiguity exists, the term “true value” may be used where the term “conventional true value” is meant. NOTE 2 See 3.1.13 of IEC 60359. 3.9 performance characteristic one of the quantities assigned to an apparatus in order to define its performance by values, tolerances, ranges, etc. 3.10 influence quantity any quantity, which is not the subject of the measurement but which influences the indication of the measuring equipment NOTE Influence quantities may interact in their effect on the measuring equipment. 3.11 variation difference between the values indicated by an analyzer for the same value of the property being measured when a single influence quantity assumes successively two different values 3.12 rated value value assigned to a performance characteristic of the analyzer by the manufacturer NOTE See 3.3.8 of IEC 60359. 3.13 range domain between the upper and lower limits of the quantity under consideration NOTE 1 The term “range” is usually used with a modifier. It may apply to a performance characteristic or an influence quantity, etc. For example, the Rated Measuring Range is the set of values of the property to be measured, corresponding to the Output Signal Range of the analyzer (for example 4 mA – 20 mA, etc). NOTE 2 See 3.3.2 of IE 60359. 3.14 span difference between the upper and lower limits of the rated measuring range 3.15 performance quality with which the intended functions of the equipment are accomplished 3.16 reference conditions appropriate set of influence quantities, with reference values with their tolerances and reference ranges, with respect to which intrinsic uncertainty is specified
3.19 specified operating range range of values of a single influence quantity which forms part of the rated operating conditions 3.20 specified measuring range set of values of the property to be measured for which the uncertainty of the analyzer is intended to lie within specified limits NOTE 1 An instrument can have several specified measuring ranges. NOTE 2 The specified measuring range can be smaller than the range of values which can be indicated, for example, on the scale. NOTE 3 This term used to be known as “effective range”. 3.21 rated operating conditions set of operating ranges for influence quantities and associated ranges of performance characteristics within which the variations of an analyzer are specified by the manufacturer 3.22 limit conditions of operation extreme conditions which an operating instrument can withstand without resulting in damage or degradation of performance when it is afterwards operated under rated operating conditions 3.23 storage and transport conditions extreme conditions which an non-operating instrument can withstand without resulting in damage or degradation of performance when it is afterwards operated under rated operating conditions 3.24 uncertainty (of measurement) dispersion of values that may be attributed to the measured quantity NOTE See 3.1.4 of IEC 60359. 3.25 intrinsic uncertainty uncertainty when used under reference conditions (see 3.16) NOTE See 3.1.10, 3.1.11, 3.1.12 of IEC 60359. 3.26 operating uncertainty uncertainty when used under rated operating conditions (see 3.21) NOTE See also 3.2.11 of IEC 60359. 3.27 relative uncertainty ratio of the uncertainty to the conventional true value (when expressed in the same units) NOTE See 3.3.4 of IEC 60359. 3.28 interference uncertainty uncertainty caused by substances other than those affecting the measured property being present in the sample
3.29 linearity uncertainty maximum deviation between indicated values and a linear function of indicated value versus the true value of the property being measured, which includes indicated values near the upper and lower limits of the rated range NOTE Linearity is a property of the electronic unit and may be verified with a simulator (see 3.4). 3.30 limits of uncertainty maximum values of uncertainty assigned by the manufacturer to the indicated values of an analyzer operating under specified conditions NOTE See 3.3.6 of IEC 60359. 3.31 repeatability spread of the results of successive measurements at short intervals of time of identical test material, carried out by the same method, with the same measuring instruments, by the same observer, in the same laboratory, in unchanged environmental conditions and with no adjust- ments made by external means to the analyzer under test NOTE 1 The spread of results should be included in the intrinsic uncertainty (see 3.25). NOTE 2 A time interval equal to about ten times the 90 % response time of the analyzer may be considered a short interval between successive measurements. 3.32 hysteresis difference in indicated values when the same value of the property being measured is applied but preceded by a lower then a higher value NOTE If repeatability is specified or measured using approaches from both upscale and downscale direction, it may include an amount due to hysteresis, i.e., which is not a truly random event. However, the contribution may be considered to be random when the analyzer is to be applied to applications where the indicated value may be approached from either direction with equal probability.