Setra's Model 760 capacitance manometer is an absolute pressure transducer designed for accurate and repeatable vacuum measurements. Various full scale ranges are available from 10 Torr up to 1000 Torr. The units of measurement may be specified in Torr, mBar/hPa, kPa or PSIA. The Model 760 operates from a ±15 VDC power supply and provides a 0-10 VDC or 0-5 VDC signal output that is linear with pressure and independent of gas composition. The electrical connection can be either the industry standard 15 pin D-sub or 6 position terminal strip connector.
Superior EMI/RFI performance is achieved by the use of a metal case, in conjunction with surge and ESD suppression components and RFI filtering on the inputs and outputs. The Model 760 has an integrated sliding cover that provides easy access to multi-turn potentiometers for fine zero and span adjustments. Inconel is used for all wetted materials allowing the Model 760 to be used with corrosive gases. A wide range of pressure and vacuum fittings are available.
The high accuracy pressure sensing element used in the Model 760 is the VactronTM sensor, which has been developed from Setra’s patented variable capacitance sensor. A centrally located feed-through assembly supports a circular electrode in close proximity to the back surface of the diaphragm. Together the electrode and diaphragm form a variable capacitor within a small reference vacuum chamber maintained at very low pressure. As the pressure increases, the diaphragm deflects and the gap between the electrode and diaphragm decreases, causing an increase in the capacitance. This change in capacitance is detected and converted to a highly accurate linear DC electronic signal by Setra’s unique custom integrated circuit, which utilizes a patented charge balance principle.