Vol.3 No.3 2010

Research paper : National electrical standards supporting international competition of Japanese manufacturing industries (Y. Nakamura et al.)−220−Synthesiology - English edition Vol.3 No.3 (2010) industrial sites through the calibration labs. In the current situation, the accreditation of the JCSS calibration labs for capacitance is progressing, and the standard dissemination system according to the initial scenario is being realized. However, the sites of production are where the metrological traceability is truly needed, and our goal is achieved only when the demands of the industrial sites are satisfied. Therefore, we thought a survey and analysis of the state of the metrological traceability system at the industrial sites were necessary. We surveyed the demand for standard dissemination system of the industries, and found that with the current dissemination system, it was difficult in terms of time and cost to guarantee the metrological traceability to each and every measuring device at the site of production. In the current system where the measuring device that must be calibrated is transported to the calibration lab for calibration (carry-in calibration), the production line where the measuring device is used must be stopped while the device is being calibrated, and this is not practical for the production line that is normally in operation 24 hours. Also, when all of the several hundred or several thousand measuring instruments used at a site of production were to be calibrated, the calibration fee will be enormous and is not realistic. Therefore, we determined that it was difficult to establish the metrological traceability system to the industrial site according to the initial scenario.Therefore, we conducted an R&D on a remote calibration method as a new dissemination method that may reduce the calibration time and cost[16]-[18]. Figure 10 shows the conceptual diagram for remote calibration of the capacitance standard. This calibration method uses an intermediate standard. Normally, to receive the calibration service, the clients must send or bring their instrument to be calibrated at their own expense and responsibility to the calibration lab. In the remote calibration shown in Fig. 10, the client uses the transfer standard and the measuring device sent by the calibration lab to conduct the measurements necessary for the calibration of the instruments on their own. Specifically, as shown in the figure, the transfer standard that has been previously calibrated by the calibration lab is sent to the client. At the same time, a switching device called the coaxial scanner is also sent. The client connects the commercial LCR meter, personal computer (PC), and the instrument to be calibrated to assemble the (remote) calibration system, starts up the measuring program installed in the PC beforehand, and conducts the measurement. The calibration system and the measurement program are designed to conduct the measurement automatically from beginning to end, and the client does not need any special training or skills. The measurement results obtained by the client are automatically sent to the calibration lab by e-mail. The data is analyzed by the calibration lab, and the result is returned to the client by e-mail. In remote calibration, the client does not have to transport the instrument outside to receive the calibration service. This will eliminate the cost needed for the transportation of the instrument, and can minimize the period during which the instrument cannot be used due to calibration. By incorporating the remote calibration method in the standard dissemination system, it will be possible to disseminate the standard to the sites of production directly from the upper-tier calibration labs, and this will rationalize the metrological traceability system as well as speed up the dissemination (Fig. 11).The external appearance of the developed remote calibration system is shown in Fig. 12. In developing this system, considering the diffusion to industry and the reduction of the Fig. 10 Conceptual diagram of the remote calibration for capacitance standardFig. 11 Quickening the service dissemination by remote calibration and rationalization of the traceability systemMeasurementprogramE-mailMeasurement data・LCR measurement value・Environmental temperature・…Coaxial scanner(switcher)LCR meterLCR meterCalibration labStandardClientInstrument tobe calibratedtransferstandardIntermediatestandardThermometerStartbuttonTransportationProgram key code・Customer ID・Measurement condition (frequency, etc.)・Measurement period・…National standard・Cost reduction・Speed upRemote calibrationRemote calibrationCalibration labIndustrial sites・Improvement of convenienceFig. 12 LCR standard remote calibration systemInstrument to be calibratedLCR meterPC (measurement program)Coaxial scanner (with built-in transfer standard)


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