Mks Instruments, Inc.

Santhi E Mathew

Claudia Quigley

Leonid Mindlin

James M Poulin

Philip J Maiorana

Donald K Smith

Stephen F Horne

J Robert Maxwell

Kerry S Lahey

Gardy St Paul

Eric R Taranto

Stephen D Blankenship

Claudia J Quigley

A system and method are described for maintaining power dissipation substantially constant across the sensor interface board of a capacitance pressure transducer. A shorted diaphragm level detector detects a shorting of the diaphragm onto one or more reference electrodes. A power dissipating resistor is placed near the oscillator that drives the capacitance detecting circuit in the capacitance pressure transducer. The resistor is switched across a power supply when the shorting is detected, causing current to flow through the resistor so that power can be added in an amount sufficient to maintain power dissipation by the oscillator substantially constant when the diaphragm shorts.

Constant power dissipation in capacitance pressure transducers

A heater is disclosed for use with pressure transducers. The disclosed heater includes a first heating element and a second heating element. The first heating element is characterized by a first electrical resistance. The second heating element is characterized by a second electrical resistance. In preferred embodiments, the first electrical resistance is different than the second electrical resistance. The disclosed heater can be used to accurately heat a pressure transducer to at least four different operating temperatures by selectively (a) connecting the first heating element to the transducer temperature control circuitry, (b) connecting the second heating element to the transducer temperature control circuitry, (c) connecting the first and second heating elements in series with the transducer temperature control circuitry, or (d) connecting the first and second heating elements in parallel with the transducer temperature control circuitry.

Multi-temperature heater for use with pressure transducers

A compensated sensor includes a sensor, a relatively fast feedthrough path, and a relatively slow compensation path. The relatively fast feedthrough path includes a summer and output circuitry, such as a summing amplifier. The relatively slow compensation path includes circuitry that produces one or more correction factors for such sensor deficiencies as temperature dependency, or nonlinearity effects, for example. These one or more correction factors are fed to the summer for summing with the uncompensated sensor output. Additionally, the output of the output circuitry (e.g., summing amplifier), is fed back to the compensation circuitry where it is compared to a compensated sensor output developed by the compensation circuitry. The difference between the compensated sensor signal developed in the compensation circuitry and the output signal fed back to the compensation circuitry is also provided to the summer for summing with the one or more correction factors and the uncompensated sensor output.

Apparatus and method for compensated sensor output

A capacitive pressure transducer including a heater shell, a capacitive pressure sensor, an electronics assembly and a thermal barrier is presented. The sensor and the electronics assembly are disposed in the heater shell. The thermal barrier is also disposed in the heater shell and is disposed between the sensor and electronics assembly.

Pressure transducer assembly with thermal shield

A method is disclosed for providing transient temperature compensation in a pressure transducer. The transducer includes a capacitive pressure sensor, the pressure sensor including a diaphragm, at least part of the diaphragm moving in response to changes in a pressure. The transducer may further include an electronic circuit which generates an uncompensated output signal representative of the pressure. The disclosed method generates a compensated output signal according to a function of the uncompensated output signal and a difference between a temperature of the pressure sensor and a temperature of the ambient environment.

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Londonderry, NH, United States of America

Santhi E Mathew