Abstract: An improved diaphragm vacuum gauge including a sensor chip that includes a first electrode provided on a base and a second electrode provided on a diaphragm so as to face the first electrode, the diaphragm and the base being disposed with a gap therebetween, and in which a distance between the first electrode and the second electrode changes in accordance with displacement of the diaphragm caused by pressure of a measurement target medium. The diaphragm vacuum gauge further includes an operational amplifier that converts a current output from the first electrode to a voltage and amplifies the voltage, and a coaxial cable that connects the first electrode and the operational amplifier with each other. Further, the first electrode is connected to a virtual ground of the operational amplifier by a core wire of the coaxial cable.

Abstract: An improved diaphragm vacuum gauge includes a pressure receiving unit having an electrical property that changes in accordance with displacement of a diaphragm caused by pressure of a measurement target medium; a heater that heats the pressure receiving unit; a temperature sensor that measures a temperature of the pressure receiving unit; a pressure measurement unit that converts a change in the electrical property of the pressure receiving unit to a pressure measurement value; a storage unit that stores a plurality of heating temperature settings; a heating temperature setting unit that selects one heating temperature setting from among the plurality of heating temperature settings in accordance with a digital input signal that is externally input; and a controller that controls power supply to the heater based on the temperature measured by the temperature sensor and the heating temperature setting selected by the heating temperature setting unit.

Abstract: A diaphragm vacuum gauge includes: a sensor chip that includes a first electrode provided on a base and a second electrode provided on a diaphragm so as to face the first electrode, the diaphragm and the base being disposed with a gap therebetween, and in which a distance between the first electrode and the second electrode changes in accordance with displacement of the diaphragm caused by pressure of a measurement target medium; an operational amplifier that converts a current output from the first electrode to a voltage and amplifies the voltage; and a coaxial cable that connects the first electrode and the operational amplifier with each other. The first electrode is connected to a virtual ground of the operational amplifier by a core wire of the coaxial cable.

Abstract: A diaphragm vacuum gauge includes: a pressure receiving unit having an electrical property that changes in accordance with displacement of a diaphragm caused by pressure of a measurement target medium; a heater that heats the pressure receiving unit; a temperature sensor that measures a temperature of the pressure receiving unit; a pressure measurement unit that converts a change in the electrical property of the pressure receiving unit to a pressure measurement value; a storage unit that stores a plurality of heating temperature settings; a heating temperature setting unit that selects one heating temperature setting from among the plurality of heating temperature settings in accordance with a digital input signal that is externally input; and a control unit that controls power supply to the heater on the basis of the temperature measured by the temperature sensor and the heating temperature setting selected by the heating temperature setting unit.

Abstract: An electrostatic capacitive pressure sensor includes: a housing having an inlet portion for a fluid; a sensor chip that detects, as a change in electrostatic capacitance, a change in a diaphragm that flexes upon receipt of a pressure of the fluid, which has entered through the inlet portion; and a baffle that prevents deposition, onto the diaphragm, of a contaminating substance included in the fluid, provided within a flow path of the fluid that is subject to measurement between the inlet portion and the diaphragm. The baffle has a cylindrical structure that is closed on one end, disposed with the direction that is perpendicular to a pressure-bearing surface of the diaphragm as the axial direction. A plurality of flow paths, in which the fluid passes between the inner peripheral surface and the outer peripheral surface of the cylindrical structure, is provided in multiple layers in the axial direction.

Abstract: A capacitance-type pressure sensor for measuring a change in a physical volume of a medium to be measured, by measuring two capacitances wherein the capacitances vary differently from each other in accordance with a change in the physical volume of the medium to be measured, provided with a function for measuring independent values for each capacitance and determining that there is an disconnect failure when at least one of these capacitance values falls below a capacitance value that indicates the normal operating range of the capacitance-type pressure sensor, to thereby provide a pressure sensor with higher reliability through performing the disconnect detection robustly.

Abstract: In a capacitance type pressure sensor (1) including capacitance detecting portions formed in opposed regions in a capacitance chamber which is at least partially formed of a diaphragm, the capacitance detecting portions being a pressure-sensitive capacitance detecting portion (101) formed in a region of the diaphragm having large sensitivity with respect to a pressure and a reference capacitance detecting portion (102) formed in a region of the diaphragm having small sensitivity with respect to a pressure, there is provided the capacitance type pressure sensor which is entirely small in size and superior in reliability by independently detecting a signal output value of the reference capacitance detecting portion (102).

Abstract: In a capacitance type pressure sensor (1) including capacitance detecting portions formed in opposed regions in a capacitance chamber which is at least partially formed of a diaphragm, the capacitance detecting portions being a pressure-sensitive capacitance detecting portion (101) formed in a region of the diaphragm having large sensitivity with respect to a pressure and a reference capacitance detecting portion (102) formed in a region of the diaphragm having small sensitivity with respect to a pressure, there is provided the capacitance type pressure sensor which is entirely small in size and superior in reliability by independently detecting a signal output value of the reference capacitance detecting portion (102).

Abstract: Disclosed is an intrinsically safe sensor signal processing circuit, permitting lower cost installation and eliminating potential hazard. In the combination of a sensor which measures physical value as process variables in hazardous environment and a safety barrier which is mounted in non-hazardous environment, an intrinsically safe sensor signal processing circuit features the safety barrier for case of mounting, wherein current limiting resistances are connected in series with the sensor and these resistances are also connected to either an output or an inverting input of OP Amps that are considered as a driver or a feeder of the sensor signal. The safety barrier can adopt blocking capacitors instead of said current limiting resistors.

Abstract: Disclosed is an intrinsically safe sensor signal processing circuit, permitting lower cost installation and eliminating potential hazard. In the combination of a sensor which measures physical value as process variables in hazardous environment and a safety barrier which is mounted in non-hazardous environment, an intrinsically safe sensor signal processing circuit features said safety barrier for case of mounting, wherein current limiting resistances are connected in series with a sensor and these resistances are also connected to either an output or an inverting input of OP Amps that are considered as a driver or a feeder of a sensor signal. And/or said safety barrier can adopt blocking capacitors instead of said current limiting resistors.

Abstract: A sensor signal processing apparatus includes a sensor section, power supply section, switching section, and CPU. The characteristics of the sensor section change in accordance with a change in physical quantity to be measured. The power supply section supplies powers of two systems having different polarities to the sensor section. The switching section is connected between the power supply section and the sensor section to switch combinations of powers of the two systems from the power supply section while preventing mixing of powers of the two systems. The CPU obtains the ratio between the differences between a plurality of signals output from the sensor section for every switching operation of the switching section.