Patent classifications
G01D3/0365
TEMPERATURE COMPENSATED MTJ-BASED SENSING CIRCUIT FOR MEASURING AN EXTERNAL MAGNETIC FIELD
Disclosed is a MTJ sensing circuit for measuring an external magnetic field and including a plurality of MTJ sensor elements connected in a bridge configuration, the MTJ sensing circuit having an input for inputting a bias voltage and generating an output voltage proportional to the external magnetic field multiplied by the bias voltage and a gain sensitivity of the MTJ sensing circuit, wherein the gain sensitivity and the output voltage vary with temperature; the MTJ sensing circuit further including a temperature compensation circuit configured to provide a modulated bias voltage that varies as a function of temperature over a temperature range, such that the output voltage is substantially constant as a function of temperature. Also disclosed is a method for compensating the output voltage for temperature.
METHOD FOR IDENTIFYING MODAL FREQUENCY OF BEAM BRIDGE BY CONSIDERING INFLUENCE OF ENVIRONMENTAL TEMPERATURE
The disclosure provides a method for identifying a modal frequency of a beam bridge by considering influence of environmental temperature. The method includes the following steps: installing a sensor on a newly-built beam bridge without damage, measuring a dynamic response of the nearn bridge cinder ambient excitation, recording temperature data, processing by a modal parameter identification method to obtain a modal frequency value at the temperature, and titarling from a modal frequency corresponding to the temperature, carrying out iterative calculation to obtain the modal frequency at any temperature. The modal frequency value at any temperature is obtained by arranging a small number of sensors and canying out a small number of tests, so that the influence of the temperature on the modal frequency is quantified, furthermore, the part of environmental influence is eliminated in future damage evaluation of the beam bridge, which allows for a more accurate isamage evaluation rttsult,
Stray Field Immune Angle Sensor
A sensor, comprising: a substrate having a reference crystal orientation and a plurality of vertical Hall element pairs that are formed on the substrate. Each vertical Hall element pair includes: (i) a respective first vertical Hall element that is oriented at a respective first angle relative to the reference crystal orientation of the substrate and (ii) a respective second vertical Hall element that is oriented at a respective second angle relative to the reference crystal orientation of the substrate. The substrate has a rectangular shape, and each of the vertical Hall element pairs is disposed in a different respective corner of the substrate.
DEVICES AND METHODS FOR MEASURING A MAGNETIC FIELD GRADIENT
A method of determining a gradient of a magnetic field, includes the steps of: biasing a first/second magnetic sensor with a first/second biasing signal; measuring and amplifying a first/second magnetic sensor signal; measuring a temperature and/or a stress difference; adjusting at least one of: the second biasing signal, the second amplifier gain, the amplified and digitized second sensor value using a predefined function f(T) or f(T, ΔΣ) or f(ΔΣ) of the measured temperature and/or the measured differential stress before determining a difference between the first/second signal/value derived from the first/second sensor signal. A magnetic sensor device is configured for performing this method, as well as a current sensor device, and a position sensor device.
Sensor temperature sensing
Sensor assemblies incorporating a temperature varying resistor provide information regarding the temperature of the operating environment for a sensor or protect the sensor from extreme temperatures. The assembly includes only two conductors—one transmitting current from a power source and another transmitting an output signal. In one embodiment, the assembly includes a sensor and a temperature varying resistor in parallel between the conductors with the output signal including information regarding a value of a variable measured by the sensor and information regarding a temperature of an operating environment for the sensor. In another embodiment, the sensor and temperature varying resistor are in series between the conductors with the output signal including information regarding a value of a variable measured by the sensor and the temperature varying resistor preventing delivery of current to the sensor when a temperature of the operating environment for the sensor meets a predetermined condition.
Reducing stray magnetic field effects using a magnetic field feedback
In one aspect, a magnetic-field sensor includes main coil circuitry configured to generate a first magnetic-field signal at a first frequency; a first channel; a second channel; a subtractor circuit configured to subtract a second channel output signal from a first channel output signal to form a subtraction signal; an adder circuit configured to combine the first channel output signal and the second channel output signal to form a summation signal; processing circuitry configured to receive the summation signal and to provide a magnetic-field sensor output signal indicating a position of the target; feedback circuitry configured to receive the subtraction signal and to provide a first feedback signal to the processing circuitry, and a second feedback signal; and a secondary coil circuitry configured to receive the second feedback signal and to generate, based on the second feedback signal, a second magnetic-field signal to reduce the first magnetic-field signal received.
MEASURING APPARATUS WITH A HOUSING AND CORRESPONDING USE
A measuring apparatus including at least one housing part including a shaped body made from a foam material.
Process variable transmitter
A process variable transmitter provides an output representing a process variable. The process variable transmitter includes a process variable sensor that provides an analog sensor signal representing a process variable, an analog to digital converter that receives the analog sensor signal from the process variable sensor and converts it to digital sensor signal values, and a compensation processor. The compensation processor calculates, in a first mode, a compensated process variable value at a first slow rate. The compensation processor calculates a compensation factor relating the compensated process variable value to an initial digital sensor signal value. The compensation processor calculates, in a second mode, a process variable estimate as a function of an updated digital sensor signal value and the compensation factor. The process variable estimate is calculated at a second rate faster than the slow rate.
TRANSIMPEDANCE AMPLIFIER-BASED REDUCTION OF HALL SENSOR PARASITIC IMPEDANCE
A high bandwidth Hall sensor includes, for example, a Hall element for generating a first polarity Hall-signal output current. An amplifier receives, at a first input, the first polarity Hall-signal output current and outputs a feedback current of a second polarity opposite the first polarity in response. The feedback current is coupled to the first input, and the feedback current suppresses an instantaneous voltage generated by the first polarity first Hall element output current at the first input. In an embodiment, the feedback current suppresses the instantaneous voltage generated by first polarity Hall element output current such that the effects of the Hall element source impedance are reduced.
POSITION SENSING SYSTEM WITH ERROR DETECTION AND CORRECTION
An actuator position sensing system for sensing a position of an actuator. The actuator position sensing system includes a first sensor for detecting a position of a first moveable portion of the actuator; a plurality of second sensors each being configured for detecting a position of a second moveable portion of the actuator; and a controller connected to the first sensor and the plurality of second sensors. The controller is configured to calculate a difference between (i) a position of the second movable portion as calculated based upon the data transmitted from the first sensor, and (ii) a position of the second movable portion as calculated based upon the data transmitted from one or more of the plurality of second sensors. A motor is connected to the first movable portion and the controller, and the motor is configured to move the first moveable portion based upon the calculated difference.