A refrigerating machine (1) is equipped with a condenser (3) through which a low-pressure refrigerant flows inside, an intermediate cooler (4), an evaporator (5), and a sensor of the atmosphere open type which is attached to at least one of the condenser (3), the intermediate cooler (4), and the evaporator (5) to measure the pressure inside at least one of the condenser (3), the intermediate cooler (4) and the evaporator (5), and a correcting unit which is configured to correct an atmospheric pressure which is a reference value of the sensor by acquiring the atmospheric pressure of a location in which the refrigerating machine (1) is installed.

A refrigerating machine (1) is equipped with a condenser (3) through which a low-pressure refrigerant flows inside, an intermediate cooler (4), an evaporator (5), and a sensor of the atmosphere open type which is attached to at least one of the condenser (3), the intermediate cooler (4), and the evaporator (5) to measure the pressure inside at least one of the condenser (3), the intermediate cooler (4) and the evaporator (5), and a correcting unit which is configured to correct an atmospheric pressure which is a reference value of the sensor by acquiring the atmospheric pressure of a location in which the refrigerating machine (1) is installed.

Described herein are techniques to enable a mobile device to perform multi-source estimation of an altitude for a location. A baseline altitude may be determined at ground level for a location and used to calibrate a barometric pressure sensor on the mobile device. The calibrated barometric pressure sensor can then estimate changes in altitude relative to ground level based on detected pressure differentials, allowing a relative altitude to ground to be determined. Baseline calibration for the barometric sensor calibration can be performed to determine an ambient ground-level barometric pressure.

Multiple calibration results for calibrating a barometric pressure sensor based on data received from a device containing the sensor are determined and stored in a table. The table is updated based on rules regarding a relationship between each calibration result and a current calibration value. The calibration results are weighted and combined to determine a combined calibration result. The calibration value for calibrating the sensor is selected from the calibration results, the combined calibration results, or the current calibration value based on a selection criteria.

In accordance with an embodiment, a sensor includes: a signal source with a first signal source terminal and a second signal source terminal; a bridge circuit connected to the first and second signal source terminals, the bridge circuit including: a first branch including: a first reference impedance element; and a first sensor impedance element configured to transduce a magnitude to be measured into a first impedance-related parameter; and a second branch including: a second reference impedance element; and a second sensor impedance element configured to transduce the magnitude to be measured into a second sensor impedance-related parameter.

A calibration system for calibrating pressure sensor comprises communication pipe, base, inlet valve, outlet valve, pump, inlet pipe, heater and reference pressure sensor. The communication pipe has first and second openings. The base comprises chamber body and outlet being disposed at the chamber body. The inlet valve is disposed at the first opening. The chamber body is connected to the second opening so as to define a space between the inlet valve and the outlet valve. The heater is to heat a fluid in the space. The reference pressure sensor is configured to measure a pressure of the fluid. The at least one target pressure sensor is detachably mounted on the chamber body via the base so as to measure the pressure of the fluid in the space.

A sensor module that includes an inertial sensor and an abnormality determination unit that determines that the inertial sensor is abnormal when a structural resonance frequency at the first time point and a structural resonance frequency at the second time point are separated by a predetermined value or more.

A pressure transmitter includes a housing and a pressure sensor having an electrical characteristic that varies with applied pressure. The pressure sensor is configured to generate a sensor signal indicative of process fluid pressure. A transmitter isolation diaphragm is configured to couple to a process barrier seal to convey pressure to the pressure sensor. A flange is coupled to the transmitter isolation diaphragm. The flange includes at least one gas pathway extending inwardly from an outer diameter of the transmitter isolation diaphragm. Electronics are coupled to the pressure sensor to receive the sensor signal and to generate an output indicative of the pressure.

A pressure sensor with calibration function includes a casing, a diaphragm, a sensing element, a medium, and at least one calibration element. The diaphragm is disposed on the casing, wherein the casing and the diaphragm define an accommodating space. The sensing element is disposed in the casing. The medium is filled in the accommodating space and in contact with the sensing element. The at least one calibration element is adjustably disposed at the casing and extended into the accommodating space to be in contact with the medium, wherein when the at least one calibration element is moved relative to the casing, the at least one calibration element changes the pressure applied to the medium.

The technology relates to techniques for lighter than air vehicle redundant pressure sensor calibration. A lighter than air (LTA) vehicle can include a redundant pressure sensor calibration system, including a high precision pressure sensor onboard the LTA vehicle and two or more additional pressure sensors onboard the LTA vehicle, where the two or more additional pressure sensors are each redundant with the high precision pressure sensor. The two or more additional pressure sensors can be calibrated based on pressure measurements from the high precision pressure sensor and the two or more additional pressure sensors at two or more altitudes, wherein the high precision pressure sensor is calibrated before a flight of the LTA vehicle.