High temperature density measurement cell with a pcmcia-interface

One of the most precise and reliable measurement methods for density measurement of liquids and gases depends on the principles of a mechanical oscillator. With this method the density is determined by measuring the natural frequency of the oscillator. Measurement devices using this method can be categorized in two groups. The first type incorporates the mechanical oscillator in the housing of the device and is mainly used in laboratories. The second type of measurement devices could be defined as evaluation units, because the sensor e.g. mechanical oscillator is external and only connected by means of electrical connections. These types are used in the field of process data control or data acquisition. The reason for separating the sensor from the evaluation unit lies in the fact that such external cells are used on remote locations in the process or the sensor is exposed to extreme physical conditions (e.g. high pressure, high temperatures). The first part of this article gives an overview about the functionality of such a high temperature measurement cell. The second part of this paper is intended to introduce a sophisticated PCMCIA interface which acts as an interface between the external density measurement cell and several hosts like PCs, PDAs or modern density measurement devices.