摘要:
A method for the compensating temperature gradient influences on a pressure measuring transducer, comprising the steps of: registering a pressure signal Sp(t); registering a temperature signal T(t); ascertaining a pressure measured value ps(Sp(t), T(t)); determining the time derivative of the temperature signal dT/dt; correcting the pressure measured value with a correction function, which depends on the time derivative, wherein, as a function of the sign of the time derivative, another correction function is selected, or other coefficients in a function of equal type are selected.
摘要:
A method for manufacturing-side calibration of a measuring device for capacitive fill level measurement of a medium, wherein at least one probe unit of the measuring device is activated with an electrical, alternating voltage of a predeterminable frequency. As a function of the frequency of the activating signal, a conductivity range is determined, within which the fill level measurement is essentially independent of a change of the electrical conductivity of the medium; for such conductivity range, at least a first reference matching between a predeterminable, first fill-level value and a first capacitance value belonging to the first fill-level value is produced; and the first reference matching between the first fill-level value and the first capacitance value is recorded. Additionally, the invention relates to a corresponding measuring device.
摘要:
An apparatus for capacitive determining and/or monitoring of fill level of a medium in a container. The apparatus includes: A probe unit; a control unit, which supplies the probe unit with a drive signal; and an evaluating unit, which receives a response signal from the probe unit and which determines from the response signal a statement concerning fill level. Stored in the evaluating unit are at least a first and a second formula or a first and a second evaluating algorithm; and, in case accretion lies below a predetermined limit value, the evaluating unit determines the statement concerning fill level via a first formula and, in case accretion lies above the predetermined limit value, the evaluating unit determines the statement concerning fill level via a second formula.
摘要:
The invention relates to an electromechanical drive or a sensor element composed of piezoelectric elements arranged in the form of a stack. The drive or the sensor element is intended for measurement instruments and operates even at very high temperatures. The new drive or the new sensor element (10) for this purpose comprises a number of piezoelectric ceramic layers (12a-f), with electrode layers (16a-e) in each case being arranged between two mutually facing surfaces of directly adjacent piezoelectric ceramic layers. Connectors (18a,b) in the form of wires run in grooves (14a-d) in the electrode layers (16a-e) in order to make electrical contact with the electrode layers (16a-e), and are passed out of the electrode layers (16a-e).
摘要:
Sensing the level of a liquid in a vessel by the pulse transit time technique is done by means of an ultrasonic transducer mounted above the highest-permissible level in the vessel which emits ultrasonic transmission pulses to the surface of the liquid and receives the ultrasonic echo pulses reflected from the liquid surface. The level in the vessel is established from the transit time of the ultrasonic pulses. To detect an overfill when the ultrasonic transducer is immersed in the liquid the decaying output signal of the ultrasonic transducer generated by the ringing of the ultrasonic transducer following the end of the each ultrasonic transmission pulse is analyzed. In this arrangement the fact is exploited that due to the better coupling of the ultrasonic transducer to the liquid than to air the ringing duration is shorter when the ultrasonic transducer is covered by the liquid.
摘要:
A method for operating a pressure sensor, which includes a measuring membrane, at least one platform and a capacitive transducer having two pressure dependent capacitances between electrodes on the measuring membrane. The measuring membrane divides a volume pressure-tightly into two volume portions, wherein the second volume portion is enclosed in a measuring chamber between the measuring membrane and the platform. A deflection of the measuring membrane depends on a pressure measurement variable p, which is a difference between a first pressure p1 and second pressure p2 in the volume portions. The pressure measurement variable p follows from both capacitances, wherein, for an intact pressure sensor, the second capacitance is a predetermined function of the first capacitance and, in given cases, the temperature. The method has steps as follows: registering value pairs of both capacitances; testing whether the value pairs correspond within a tolerance range to the predetermined function; and determining a change, respectively damage, of the sensor, when this is too long not the case.
摘要:
A method for embossing a separating membrane of a pressure transfer means including a membrane carrier having a membrane bed. With the method, an optimal forming of the separating membrane matched to the form of the membrane bed is achievable. The method includes steps of: welding a planar, separating membrane blank onto the membrane carrier; filling with a lubricant a pressure receiving chamber enclosed by the welded, separating membrane blank and the membrane carrier; producing the separating membrane from the separating membrane blank by embossing the separating membrane blank by pressing it against the membrane bed while lubricant is present in the pressure receiving chamber.
摘要:
A pressure measuring device having a pedestal, an intermediate piece of semiconductor arranged on the pedestal and, connected with the pedestal and arranged on the intermediate piece and connected with the intermediate piece, a semiconductor pressure sensor having a support and a measuring membrane, or diaphragm. The pressure measuring device offers reliable protection of the sensitive measuring membrane, or diaphragm, against mechanical distortions. Provided extending in the interior of the i[ntermediate piece is an annular cavity, which surrounds a first cylindrical section and, pedestal end thereof, a second cylindrical section of the intermediate piece. The second cylindrical section has a greater outer diameter than the first cylindrical section. The cavity is open on an end of the intermediate piece toward the pedestal. The second cylindrical section has an end face facing the pedestal and lying on an end face of the pedestal, for forming a connecting area, via which the intermediate piece is mechanically connected with the pedestal.
摘要:
A method for manufacturing-side calibration of a measuring device for capacitive fill level measurement of a medium, wherein at least one probe unit of the measuring device is activated with an electrical, alternating voltage of a predeterminable frequency. As a function of the frequency of the activating signal, a conductivity range is determined, within which the fill level measurement is essentially independent of a change of the electrical conductivity of the medium; for such conductivity range, at least a first reference matching between a predeterminable, first fill-level value and a first capacitance value belonging to the first fill-level value is produced; and the first reference matching between the first fill-level value and the first capacitance value is recorded. Additionally, the invention relates to a corresponding measuring device.
摘要:
An apparatus for establishing and/or monitoring a pre-determined filling level in a container is provided, in which the reception signal (E) corresponds to the desired measurement signal and in which a fixed phase difference (.DELTA..phi..sub.R), which is independent of the oscillation quality of the apparatus, exists between the transmission signal and the reception signal (E) at the resonant frequency (f.sub.r) of the mechanical oscillatory structure (1). The apparatus comprises a mechanical oscillatory structure (1) and a piezoelectric element (2), which has at least three regions, a first region (I) having a transmission electrode (21), a second region (II) having a first reception electrode (22) and a third region (III) having a second reception electrode (23), the two reception electrodes (22, 23) having an identical form and being arranged symmetrically with respect to one another and to the transmission electrode (21), and in the first and in the second region (I, II), the piezoelectric element (2) having a polarization which is in the opposite direction to a polarization of the third region (III). The reception signal (E) is equal to the difference between a first signal (E.sub.1), which is present at the first reception electrode (22), and a second signal (E.sub.2), which is present at the second reception electrode (23).