Evaluation of a 500-N deadweight force standard machine at NIMT

摘要

A 500-N deadweight force standard machine (DWM) has been developed for calibrating force proving instrument of small force ranges at National Institute of Metrology, Thailand (NIMT). The DWM is able to generate calibration forces ranging from 2 N to 500 N with the relative expanded uncertainty of 5×10~(-5). This machine can be divided into six calibration ranges, which are 10 N, 20 N, 50 N, 100 N, 200 N and 500 N. To verify performance of the machine, this paper shows the evaluation of relative uncertainty in the range of 50 N to 500 N. The force transducer was calibrated by the machine according to ISO376:2011[1]. The calibration result of force transducers has shown repeatability and reproducibility. The relative deviation of the calibration errors were less than 5×10~(-5) at the 50% to 100% of the capacity of force transducer.