Proceedings

Traceability concept teaching by means of experimental procedures for chemistry undergraduate students at UNAM.

Activities designed to establish relationships between concepts as a didactic strategy in the metrology teaching process

The teaching of metrology in undergraduate courses includes concepts such as traceability, calibration and uncertainty. This paper proposes a certain activity that students will have to realize in the Metrology Laboratory. The purpose of this activity is that students understand the contribution that the traceability chain has in the estimation of the uncertainty of a measurement. The activity should be realized in three stages. The first one consists of the construction of a mass measuring device. In the second stage, the pupil realizes the calibration of the device with two different...

Measurement of gravitational acceleration values at the calibration laboratories in Korea

The most important conversion factor between mass and force is the value g of the acceleration due to gravity. This can be measured with an absolute or relative gravimeter. It depends on the latitude and height above sea level. Values of g at many calibration laboratories in Korea are measured with a relative gravimeter, Model G manufactured by La Coste & Romberg in USA. To improve the measurement performance of the gravimeter, we attached an optical magnifying system instead of microscope eyepiece, which consists of CCD camera and LCD display. This optical system showed to be sufficiently...

Analysis of Change of Mass Difference between Weight Support Plates during Subdivision of 1 kg

In the research a possibility was studied how to reduce a number of repetitions of measurements when performing dissemination of 1 kg mass standard and at the same time maintain the level of confidence of the measurement results. The method considered is designed for weighing schemes where a pair of support plates for weights is required to carry out comparisons of combinations of weights on comparators with automatic weight handler and the same pair of support plates is used for many of the compared weight combinations. The results of analysis indicate to minor relation between the changes...

Traceable Low Frequency AC Voltage Measurements

The International Organization for Standardization (ISO) has developed a set of standards for the calibration of vibration and shock transducers. Method 3 of ISO 16063 part 11, deals specifically with the primary calibration of accelerometers over the frequency range 1 Hz to 10 kHz. Many NMIs have implemented the method over a wider frequency range. One of the difficulties faced by said NMI, is the provision of traceable low frequency AC voltage measurements. This paper considers low frequency AC voltage traceability options and investigates in more detail a measurement option defined as DC...

Development of Shock Acceleration Calibration Machine in NMIJ

Calibrations of shock acceleration are industrially required from a view of human safety and product development. In NMIJ vibration group, a shock acceleration calibration machine (hereafter ‘calibration machine’) has been developed in response to much demand from Japanese industries, and can calibrate shock transducers in acceleration range from 200 m/s² to 5000 m/s². For primary calibration, accelerometer is calibrated by a combination of shock exciter and laser interferometer. In the shock exciter, shock acceleration is generated by rigid body collision between a hammer and an anvil. To...

Dynamic Structure Evaluation of Isolation Seismic Block for Primary Vibration Calibration System

According ISO 16063-11 the exciter and interferometer of primary vibration calibration system must be mounted on heavy seismic block so as to prevent unwanted vibration from having effects on the calibration results. To improve the current low frequency primary vibration calibration system National Measurement Laboratory (NML) design and manufacture a new heavy seismic block. The new block which is made of case iron and its mass is about 4000 kg. The block’s dimension is 2000 mm × 600 mm × 700 mm. In order to evaluate the block dynamic characteristic we apply experimental modal method and...

Comparison of the Calibration of a Heavy Multi-Component Vibration Transducer on Different Exciter Systems (Calibration of Heavy Triax-Transducer)

The performance specifications of a shaker may be strongly affected by the load which it is driving. When using a shaker for calibration purposes, the mass and mass distribution of the device under test as well as its mounting configuration may deteriorate seriously the purity of the motion of the shaker armature along the desired axis. In this paper the authors present an attempt to reduce the magnitude of parasitic movements by an improved mounting configuration. Although the resulting motion is significantly improved, transverse, bending and rocking acceleration could not be diminished to...

Development of charge amplifier calibration system employing substitution method

Charge amplifier is a key device for vibration metrology as well as an accelerometer itself. Reliability of vibration measurement heavily depends on the stability and frequency characteristics of charge amplifier. Especially, phase characteristic of charge amplifier becomes more important as many calibration sectors have adopted Sin-approximation method which enables calibration of accelerometer phase shift. In this paper, development of charge amplifier calibration system both for amplitude (gain) and phase is reported. The calibration system consists of standard capacitor, inductive...

The development of a new primary calibration system for laser vibrometers at INMETRO

The laser vibrometer (LV) is a powerful non-contact transducer capable of accurately measuring point motion quantities by means of interferometric techniques. According to the requirements in standard ISO/IEC 17025, measurement traceability to the International System of Units (SI) is to be established through an unbroken chain of calibrations, linking measuring and testing equipment to the national or international measurement standards. At present, standard procedures specifying how to calibrate a laser vibrometer are still an open issue. As laser vibrometers are becoming more and more a...