This paper deals with measurement and control of the standard gas cylinder. In CMS (Center of Measurement Standard), the mass measurement technology is used to calibrate the concentration of standard gas cylinders. This measurement method is based on the mass change of gas cylinder before and after filling. By using balance and calculating air buoyancy the mass difference of gas cylinder before and after filling could be obtained. In order to understand stability of the gas cylinder, we use statistical control techniques to monitor the change of concentration of the standard gas cylinders, to take immediate measures when the concentration of the standard gas cylinders is changed.

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Specifying and reducing the uncertainty is very important to all kinds of measurements. In order to have a better understanding of the noise mechanism responsible for lowering the quality of mass/force measurements, the Allan variation method is applied to investigate the noise performance of a commercial ultra-microbalance installed on different noise reduction platforms. It turns out that the marble table provides a better noise isolation environment for mass measurements than an optical table. The optimal integration time is found to be 100 sec ~ 200 sec, with a lowest deviation of 0.07 µg. A different data treatment simulating the ABA load/unload cycle is also applied with or without a delay time for signal integration. The consistency between Allan deviation and the ABA simulation plots points out that the optimal integration time is applicable either in single or cyclic mass measurements.

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