Abstract: Systems and methods related to a flow meter and/or flow meter operation can include one or more sensors and be capable of detecting parameters of the fluid flowing the flowmeter. One or more sensors can include capacitive sensors having a plurality of electrodes and configured to detect capacitive properties of a fluid flowing through the flow meter. Detected changes in detected properties of the fluid can be evidence of important changes in the fluid, such as an out of product event or a contamination of the fluid.

Abstract: A method for compensating for a dielectric absorption effect in a measurement configuration during measurements by an instrument having measurement terminals includes providing a feedback loop in the instrument, the loop having a gain adjustment and a simulation impedance and being adapted to provide a signal counter to the dielectric absorption at the measurement terminals; applying a transient calibration signal to the test terminals for at least two values of the gain adjustment; measuring a response to the calibration signal for each of the at least two values; and determining an operating value of the gain adjustment based on the measured responses. The operating value is used for subsequent measurements by the instrument, the simulation impedance modeling the dielectric absorption characteristics of the measurement configuration.

Abstract: A gas sensing device that includes differential temperature compensation.

Abstract: In a capacitance detecting device including an offset adjustment circuit for removing offset from charge transmitted to an integrator from a charge reading mechanism, the offset adjustment circuit includes a variable capacitance element switching the number of capacitative elements connected in parallel to a charge transmission line made up of a plurality of the capacitative elements and setting the number to a predetermined capacitance value; and a capacitative element for adjustment connected in parallel to the variable capacitance element and parallel, and having a capacitance value corresponding to the minimum value of the capacitative elements constituting the variable capacitance element. Driving is controlled so that offset removal is performed only N times (M>N; M and N are natural numbers) in the capacitative element for adjustment while offset removal is repeated M times in the variable capacitance element.

Abstract: A capacitive sensor device includes first and second sensor capacitors coupled in series, a clock signal generating part, an operational amplifier, a feedback capacitor, a compensating capacitor, and a compensating signal generating part. The clock signal generating part generates a first clock signal and the second clock signal applied to the first and second sensor capacitors, respectively. The compensating signal generating part generates a compensating signal applied to the compensating capacitor. The first clock signal and the second clock signal have the same frequency and the same amplitude and have phases being opposite each other. The compensating signal has a frequency same as the first clock signal and the second clock signal, has a phase same as one of the first clock signal and the second clock signal, and has an amplitude that is adjustable.

Abstract: Disclosed is method for compensating for variation in the capacitance between multiple capacitive sensors. Prior to sensing operations, baseline capacitance values can be acquired for all sensors. A correction factor can be calculated based on such baseline values. During sensing operations (run-time), variations in capacitance from baseline values can be modified by appropriate correction factors. Sensitivity between sensors can thus be made more uniform.

Abstract: Capacitive gauge for fuel tank comprising a measurement capacitor, a reference capacitor and at least one standard capacitive device, fed by and connected to an electronic interpretation circuit comprising switches for charging and discharging the capacitors and the capacitive device at a certain frequency; an integrator to which the charges of the measurement or reference capacitor can be transmitted and accumulated before being discharged into the standard capacitive device; a comparator for comparing an output value of the integrator with a threshold value; a counter; and a processor or computation unit for calculating the level of liquid in a fuel tank according to the equation: h=[nref,empty/(nref?nref,empty)]·[(nmeas?nmeas,empty)/nmeas,empty], where n are the values read by the counter respectively for the capacitance of the reference capacitor when empty (nref,empty), for the capacitance of the reference capacitor immersed in the fuel (nref), for the capacitance of the measurement capacitor when empt

Abstract: Disclosed is method for compensating for variation in the capacitance between multiple capacitive sensors. Prior to sensing operations, baseline capacitance values can be acquired for all sensors. A correction factor can be calculated based on such baseline values. During sensing operations (run-time), variations in capacitance from baseline values can be modified by appropriate correction factors. Sensitivity between sensors can thus be made more uniform.

Abstract: A capacitive rain sensor for activating automotive window wipers includes: capacitive plates, electronic circuitry for sensing the capacitance between said plates, processing the sensed capacitance signal, and generating wipe commands. The capacitive plates are protected from water adsorption and condensation by means of a hermetic enclosure. The interconnection between the inside and outside of the enclosure is optionally implemented by means of conductors printed on the window. Wiper-induced and other parasitic signals are rejected by means of an adaptive filter Optional radiation sensor is utilized to suppress solar induced fast temperature variations. An optional far-field cancellation plate is utilized to minimize false wipes due to nearby objects.

Abstract: A longitudinal balance measuring bridge circuit includes a common mode signal injection circuit in the form of a center tapped, 4:1 balanced matching transformer. The signal injection circuit is coupleable to an item under test (IUT) and to a source of common mode signal, and provides the common mode signal to the IUT. The common mode signal injection circuit includes balanced outputs. A common mode filter is coupled to the balanced outputs of the common mode signal injection circuit and attenuates the common mode signal. The common mode filter also includes balanced outputs on which are provided a transverse signal resulting from the common mode signal provided to the IUT. A signal output balun is coupled to the balanced outputs of the common mode filter and converts the transverse signal to an unbalanced signal.

Abstract: The present invention relates to a system for nulling drive feedthrough error in a sensor having first and second drive electrodes which impart vibratory motion to first and second proof masses in response to first and second opposite phase drive signals, and having first and second capacitances defined between the drive electrodes and their associated proof masses. A mismatch between the first and the second capacitance is measured. Drive feedthrough caused by the measured capacitance mismatch is nulled by adjusting the relative amplitudes of the first and second opposite phase drive signals, whereby the ratio of the amplitudes is proportional to the ratio of the first and second capacitances. A servo loop may adaptively effect the ratio of amplitudes.

Abstract: A capacitance measurement circuit and probe includes a drive circuit couplable to a constant-current source, a threshold detector, a probe capacitor, and a reference capacitor. The circuit includes a plurality of switches being actuatable to alternately couple the current source to the probe capacitor and to the reference capacitor. The drive circuit is configured to alternately generate a signal of linear ramp waveform having a slope that is proportional to the magnitude of capacitance of the probe capacitor and of the reference capacitor. The voltage differential between the probe capacitor and reference capacitor are actively nulled to nominally eliminate a parasitic capacitance therebetween.

Abstract: The device for measuring the capacitance of electrical wires has a first and a second measuring tube both connected to a voltage source of high frequency. The first measuring tube has a conventional length while the second measuring tube is significantly shorter. With the first measuring tube the capacitance of the wire can be measured in a conventional manner. The second measuring tube allows the measurement of local changes of the capacitance.

Abstract: A capacitive sensor for detecting raindrops on the external surface of a vehicular windshield, relying for its operation on the compensation of the capacitive signals which are due to variation of the dielectric constant of the windshield's glass with temperature, and on the elimination of capacitive signals which result from electrostatic interference or moisture deposition occurring at the inner surface of the windshield. The sensor includes electrodes printed on the internal surface of the windshield and is shielded by a grounded conducting enclosure. Another embodiment of the invention simultaneously senses raindrops on the external side of the window and moister on the internal surface of the windshield.

Abstract: A detection circuit which is capable of outputting a voltage proportional to a static capacitance of a sensor is provided, which comprises a voltage input terminal connected to receive an input voltage and an operational amplifier. The input voltage received at the voltage input terminal is changed between two different reference voltages. An inverting input terminal of the amplifier is connected to the voltage input terminal through a resistor, and a non-inverting input terminal of the amplifier is connected to the voltage input terminal through the sensor capacitance and to one of the reference voltages through a switch. An output voltage of the amplifier is connected to the inverting input terminal through a feedback circuit including a resistor and a switch. The switches are closed and the one of the reference voltages is supplied to the input terminal during an initialization cycle. The switches are opened and the other reference voltage is supplied to the input terminal during a measurement cycle.

Abstract: A measuring transmitter assembly using the same lines for power input and for output signals and using a single power supply, has a first power input and signal output loop coupled to the power supply, a second power input and signal output loop coupled to the power supply, a first sensor for providing a first input signal in response to the value of a first parameter and a second sensor providing a second input signal in response to the value of a second parameter, and a controller coupled to the first and second sensors. The controller is also coupled to the first and second power input and signal output loops and provides a first output signal on the first power input and signal output loop in response to the first input signal and a second output signal on the second power input and signal output loop. The second output signal may be in response to only the second output signal or it may be in response to the first and second input signals.

Abstract: A time varying excitation current (413) is provided to one side of a capacitive sensor (417), and two signal paths (420,430) are provided between the other side of the capacitive sensor (417) and signal conditioning circuitry (412), each signal path differing from the other according to its polarity. The signal paths conduct monopolar signals from the capacitive sensor the magnitude of which are directly related to the capacitance of the sensor, and bi-polar signals the magnitude of which are directly related to the stray capacitance in the signal lines. The combined monopolar and bi-polar signal currents on each signal line are converted into voltage signals (422,433), and the voltage signals are thereafter differenced (460) to provide a null bi-polar output while providing a constant monopolar voltage level the magnitude of which is directly related to the probe capacitor current.

Abstract: An instrument system provides compensation for signal processing errors by processing both sensor signals and reference signals in a common signal processor. Reference signals may be provided which enable zero compensation, gain compensation, or both. The system outputs compensated signals to a two wire signal loop in either analog or digital form, and selects the form of output signal in accordance with digital input signals received from the signal wires. The system may be embodied as a radio frequency admittance instrument system for monitoring the condition of materials.

Abstract: An apparatus and method are provided for calibrating a measuring transmitter which provides an output signal proportional to a parameter of interest measured by a sensor in the measuring transmitter without removing the measuring transmitter from its normal operating position. The apparatus includes a housing, a calibration sensor element located in the housing for sensing said parameter of interest, and a tube for coupling the housing to the measuring transmitter, thereby exposing the calibration sensor to the same parameter of interest as the measuring sensor in the measuring transmitter.

Abstract: Digital tilt level sensing probe system comprising a set of multiple capacitor elements in a fluid container arranged along an axis of measurement where each multiple capacitor element represents a discrete level increment in dielectric material fluid to be measured. Individual capacitors in each element are horizontally spaced to reflect a level differential upon tilting of the fluid container from its normal attitude. In the case of a probe for sensing tilting in a single plane, a one-piece body is employed to include integral capacitor elements, mounting pad, connector, custom IC pad, and circuitry molded into such body. Alternative references may be employed for comparison with each capacitor assigned a unique time slot in a switching sequence.

Abstract: Apparatus and method for determining the water content of an oil and water mixture such as is transported by pipelines and which oil and water may vary in density from time to time. A densitometer measures the density of the oil and water mixture in the pipeline and a value for the dielectric constant of the oil is obtained from the density measurement by correlating the density reading with a capacitance or dielectric constant reading from an empirically generated chart. A basal sediment and water instrument measures the dielectric constant of the same mixture. The difference between the two dielectric constants is then obtained. This result is converted directly into a water based percentage by volume of the oil-water mixture being carried by the pipeline.

Abstract: A moisture sensitive device includes a polymer capacitive moisture sensitive element and a heater. The polymer capacitive moisture sensitive element is formed by sequentially stacking a lower electrode, a moisture sensitive film made of an organic polymer resin material, and an upper electrode on an insulating substrate. The heater serves to heat the moisture sensitive film to restore the original characteristics thereof.

Abstract: A test apparatus for determining a given property, by weight, such as moisture content, of a material such as a grain or the like, comprises a chamber for receiving a sample of material to be tested, having an open top portion through which the material may be introduced therein for testing. An electrical circuit is operatively coupled with the chamber for producing an electrical measurement signal corresponding to the property to be determined and an indicator provides an observable indication of the given property of material in accordance with the corresponding electrical measurement signals. A measurement initiating control in responsive to the accumulation of a predetermined measurement weight of material in the chamber for initiating the operation of the circuit. A further warning control is responsive to the weight of material in the chamber reaching a second, predetermined warning weight slightly less than the predetermined measurement weight for producing a warning signal.