An apparatus for calibrating a pressure sensing device having a pressure sensor and a temperature compensation device includes: a chamber for applying a variable temperature and a variable pressure to the pressure sensing device; a temperature regulation device for regulating the temperature in the chamber designed such that the temperature in the chamber respectively increases in a strictly monotonous manner or falls in a strictly monotonous manner during one or more time intervals; a pressure regulation device for regulating the pressure in the chamber designed such that the pressure in the chamber respectively monotonously increases or respectively monotonously falls in at least one of the time intervals during a plurality of sub-intervals of the one-time interval; a reference pressure sensor for sensing the pressure in the chamber during the time interval(s); and a data record generation device for generating corresponding data records.

Certain implementations of the disclosed technology may include systems, methods, and apparatus for a sealed transducer with an adjustment port. The sealed transducer may include one or more terminals. A first terminal may include electrical connections for connecting to an input voltage source, a ground, and for providing a transducer output signal. A second terminal, for example, may include an electrical port for connecting to an external and separately sealed adjustment network. In one example implementation, the adjustment network can include one or more components configured to couple with internal circuitry of the transducer to alter a response of the transducer.

In order to provide a vacuum monitor that, even if a sensing mechanism is exposed to an atmosphere into which various types of material gases are introduced, enables the deposition of matter on the sensing mechanism to be prevented, and enables the lifespan of the sensing mechanism to be extended, there are provided a sensing mechanism that is in contact with an atmosphere inside a measurement space, and outputs an output signal that corresponds to a pressure inside this measurement space, and a heater that adjusts a temperature of the sensing mechanism, wherein a set temperature of the heater is adjustable.

The invention is a method for determining an output value, which is equivalent to a pressure or a value proportional to the pressure, comprising a relative pressure sensor with at least one measured capacity formed between a basic body and a measuring membrane and at least one reference capacity formed between the basic body and the measuring membrane, with the determination of the output value comprising at least the following steps: (1) determining the measured capacity, (2) determining the reference capacity, (3) comparing a value of a first function F.sub.Z of the reference capacity to the measured capacity and (4) issuing
A=F.sub.Q(C.sub.M,C.sub.R) for C.sub.M=F.sub.Z(C.sub.R)
A=F.sub.CR(C.sub.R) for C.sub.M>F.sub.Z(C.sub.R)
A=F.sub.CM(C.sub.M) for C.sub.M<F.sub.Z(C.sub.R)
as the output value.

A method of driving a pump is used in a pressure-applying apparatus, the apparatus including a flow passage, a pump configured to impart pressure into the flow passage, an opening and closing valve configured to open and close the flow passage, a pressure detector configured to detect pressure in the flow passage, and an atmospheric air open valve configured to open an interior of the flow passage to atmospheric air. The method includes driving the pump after closing the opening and closing valve and opening the atmospheric air open valve, and evaluating a state of the pump, based on one of: the pressure detected by the pressure detector at a time at which a predetermined time period has elapsed after closing the atmospheric air open valve, and a time from closing of the atmospheric air open valve until detection of a predetermined pressure by the pressure detector.

A pressure measuring sensor having a ceramic pressure sensor includes a temperature transducer to provide a thermovoltage dependent on a temperature gradient. The temperature transducer includes two series-connected thermoelements, each of which has a galvanic contact between a wire of the thermoelement and a connecting conductor connecting the galvanic contacts of the two thermoelements to one another. The temperature transducer enables the compensation for a measuring error caused by a temperature gradient occurring along the pressure measuring sensor.

The present invention makes it possible to, even when a stainless steel is adopted in a diaphragm: prevent the diaphragm and a strain sensor from exfoliating from each other; be hardly susceptible to the influence of temperature in an operating environment; not allow the sensitivity of a pressure sensor to be dominated only by the mechanical characteristic of a material constituting the diaphragm; and increase the degree of freedom in design of members constituting the pressure sensor. A pressure sensor according to the present invention is, in order to solve the above problems, characterized in that: the pressure sensor has a diaphragm deforming by the pressure of a fluid, an elastic body covering the whole surface of the diaphragm and joining to the diaphragm on one side, and a strain sensor being arranged by joining on the other side of the elastic body and on an end side apart from a position corresponding to the center of the diaphragm and detecting the deformation of the elastic body working together with the deformation of the diaphragm as a strain; and the elastic body is formed of a material having a linear expansion coefficient close to the linear expansion coefficient of a material constituting the strain sensor.

A pressure change measuring unit causes a temperature control unit to operate and vary the temperature of a sensor chip in a predetermined temperature range, and measures changes in pressure value output from the sensor chip whose temperature is being varied. A temperature characteristic calculating unit calculates a temperature characteristic of the sensor chip from changes in the temperature of the sensor chip caused by the operation of the temperature control unit and changes in pressure value measured by the pressure change measuring unit.

A method for compensating a temperature shock at a capacitive pressure measuring cell is disclosed, the method employs a measuring capacitor and a reference capacitor, wherein in an evaluation unit a pressure measurement value p is obtained by forming the quotient Q from the capacitance values of the reference capacitor and the measuring capacitor and a pressure measurement value p.sub.M is obtained by use of the measuring capacitor, wherein the temperature shock is detected by comparing the pressure measurement values p and p.sub.M with each other and monitoring the gradient dD of the difference value D of the two values with respect to exceeding a predetermined threshold value. The intensity of the temperature shock is determined based on the gradient dD of the difference value D, whereby the influence of error can be counteracted very quickly and the duration of the influence of error is also very short.

A sensor interface circuit includes a continuous-time capacitance-to-voltage (C/V) converter having C/V input and output ends, the C/V input end being configured for electrical connection with first and second sense nodes of a capacitive sensor. A filter circuit is electrically coupled to the C/V output ends. The filter circuit has first and second resistors at corresponding first and second filter input ends of the filter circuit, a capacitor connected between first and second filter output ends of the filter circuit, and a chopper circuit interposed between the first and second filter input ends and the first and second filter output ends. A buffer circuit is electrically coupled with the first and second filter output ends of the filter circuit. The filter circuit applies low pass filtering of sense signals from the capacitive sensor before sampling and demodulation operations to reduce high-frequency interference in the sense signals.