ANALYSIS OF PERFORMANCE PARAMETERS OF ILLUMINANCE METERS PER CIE DS 023 QUALITY INDICES FOR SPECIFIC FIELD MEASUREMENTS

摘要

Illuminance meters and luminance meters are widely used instruments for many types of field measurements. Characterization of performance of these devices was formerly made according to CIE 69:1987 recently updated by the draft standard CIE DS 023/E:2012 which if would be approved by the CIE national commities, it will be published as a CIE Standard and later on as a joint ISO/CIE standard. But the problem of user as describe this draft standard is the characteristics of these photometers alone do not allow the estimation of the measurement uncertainty for a specific measurement task even if on the other hand it describes that instruments with "better" characteristics in most cases allow smaller uncertainties than instruments with "worse" properties. Often users do not know according to quality indices evaluate measurement uncertainties of their measurement especially in the field photometric measurements of illuminance or luminance. This ambiguity appears in the at the verification measurements of lighting systems after realisation of lighting project or others specific measurements in the field. This paper concerns about analysis of measurement uncertainties for specific field measurements of illuminance with different classes of illuminance meters defined by the draft standard CIE DS 023/E:2012. The main aim of research work was made about field measurements for indoor workplaces under well-known conditions. Lighting system parameters according to EN 12464-1 indoor work places (i.e. average maintained illuminance level E_m, uniformity U_0 etc.) and spectrum of used light sources (in luminaires) in the measured rooms was known to compare results of measurements with stated expanded uncertainties for 95% confidance interval (k=2) assuming of normal distribution. Uncertainties of measurement in this specific field measurement was investigated for different types of illuminance meters from worse classes to the best classes of quality assuming quality indices prescribed in the draft standard. From results of this work can be in some level to be helpful to predict the accuracy of measurement of used illuminance meters with concrete class to avoid ambiguity for user who performs field measurements with them.