Abstract: A pressure sensor that is particularly suitable inter alia for the food industry and the measuring accuracy of which is stable over a long time, having a diaphragm seal (3, 45) with a separating diaphragm (7, 53) on which a pressure (P) to be measured acts and having a ceramic measuring cell (9, 57) which is connected to the diaphragm seal (3, 45) exclusively by inorganic materials, is provided, in which sensor the separating diaphragm (7, 53) and all further sensor components coming into contact during measurement with a medium of which the pressure (P) is to be measured are metallic.

Abstract: A pressure sensor that is particularly suitable inter alia for the food industry and the measuring accuracy of which is stable over a long time, having a diaphragm seal (3, 45) with a separating diaphragm (7, 53) on which a pressure (P) to be measured acts and having a ceramic measuring cell (9, 57) which is connected to the diaphragm seal (3, 45) exclusively by inorganic materials, is provided, in which sensor the separating diaphragm (7, 53) and all further sensor components coming into contact during measurement with a medium of which the pressure (P) is to be measured are metallic.

Abstract: A description is given of a measuring instrument to be connected to a higher-order unit having at least a first and an identical second pair of terminals, which can be connected electrically, very simply and without errors, to the higher-order unit, the measuring instrument comprising: a first pair of lines, to be connected to the first pair of terminals, via which a signal current flows during operation, the signal current being a measure of an instantaneous measured value, and a second pair of lines, to be connected to the second pair of terminals, via which a supply current flows during operation, whose value is greater than or equal to a minimum signal current and less than or equal to a maximum signal current.

Abstract: A pressure sensor that is particularly suitable for the food industry and the measuring accuracy of which is stable over a long time, having a diaphragm seal with a separating diaphragm on which a pressure to be measured acts and having a ceramic measuring cell which is connected to the diaphragm seal exclusively by inorganic materials, is provided, in which sensor the separating diaphragm and all further sensor components coming into contact during measurement with a medium of which the pressure is to be measured are metallic.

Abstract: A description is given of a measuring instrument to be connected to a higher-order unit (57, 75) having at least a first and an identical second pair of terminals, which can be connected electrically, very simply and without errors, to the higher-order unit, the measuring instrument (61) comprising: a first pair of lines (1), to be connected to the first pair of terminals, via which a signal current flows during operation, the signal current being a measure of an instantaneous measured value, and a second pair of lines (3), to be connected to the second pair of terminals, via which a supply current flows during operation, whose value is greater than or equal to a minimum signal current and less than or equal to a maximum signal current.

Abstract: A pressure sensor that is particularly suitable inter alia for the food industry and the measuring accuracy of which is stable over a long time, having a diaphragm seal (3, 45) with a separating diaphragm (7, 53) on which a pressure (P) to be measured acts and having a ceramic measuring cell (9, 57) which is connected to the diaphragm seal (3, 45) exclusively by inorganic materials, is provided, in which sensor the separating diaphragm (7, 53) and all further sensor components coming into contact during measurement with a medium of which the pressure (P) is to be measured are metallic.

Abstract: Evaluation unit of a differential-pressure sensor An evaluation unit of a differential-pressure sensor is provided which supplies an output signal which corresponds to a differential pressure (.DELTA.P) which has been corrected with respect to a measuring error due to the static pressure (P.sub.S). The differential-pressure sensor has a capacitive single-chamber differential-pressure measuring cell with two capacitors (4, 5) as sensor element (1), and a temperature sensor (6) is arranged at the sensor element (1). The differential-pressure measured value is corrected by means of a first correction value (.DELTA.K) which is a measure of the static pressure (P.sub.S) at a reference temperature (T.sub.R). This correction value (.DELTA.K) is determined from the difference between a sensor temperature (T.sub.S) determined by means of the temperature sensor (6) and a sum of a temperature discrepancy (T.sub.0) and an internal temperature (T.sub.i) assigned to the sum (.SIGMA.

Abstract: For measuring the level of a material in a container on the basis of the radar principle, microwaves are radiated downwards and reflected microwaves received by means of the antenna of a ranging device arranged above the highest level anticipated. In the normal measuring operation the received microwaves are evaluated in the distance range up to empty distance corresponding to the distance of the antenna from the bottom of the container for determining the echo waves reflected from the surface of the material, for measuring the transit time of the echo waves and for computing the distance of the material surface from the antenna of the ranging device from the measured transit time.

Abstract: A level measuring device using microwaves comprises an antenna for sending transmitted waves toward the surface of a material whose level is to be measured, and for the reception of echo waves resulting from reflection at the surface, and a receiving and evaluating circuit which derives from the echo waves received by the antenna an echo function representative of the echo amplitudes as a function of the distance and determines from the echo function the transit time of the microwaves from the antenna to the surface of the material and therefrom the distance of the surface of the material from the antenna.

Abstract: Provision is made for a pressure sensor with a ceramic sensor element (1) which is introduced in a gas-tight manner, having a metallic housing (2) and having a metallic adapter (3) which is arranged between the sensor element (1) and housing (2) and which is connected in a gas-tight manner both to the housing (2) and to the sensor element (1).

Abstract: In a method of level measurement on a radar basis, microwaves are emitted by means of an antenna to the surface of a material in a container and the echo waves reflected from the surface thereof are received. An actual echo function representing the echo amplitudes as a function of the distance is formed from the echo waves received by the antenna for each measurement, the probable useful echo and the transit time thereof are established from the actual echo function, and the distance of the material surface from the antenna is determined therefrom. To recognize the formation of a deposit and/or other trouble, such as e.g. damage to or loss of the antenna, an undisturbed echo function corresponding to an undisturbed measurement is obtained and stored prior to performing the measurements. In each measurement the actual echo function is compared to the stored undisturbed echo function.

Abstract: The differential pressure measuring apparatus comprises a single chamber differential pressure sensor having two resilient sensor diaphragms which enclose a volume filled with a fluid. In the single chamber differential pressure sensor two measuring capacitors are formed whose capacitances vary in opposite senses in response to the sensor differential pressure between the pressures acting on the two sensor diaphragms. The single chamber differential pressure sensor is connected to an adaptor comprising a volume filled with a fluid which is closed on the one hand by one of the two sensor diaphragms and on the other hand by an elastic adaptor diaphragm. An evaluation circuit calculates the sensor differential pressure from the capacitances of the measuring capacitors.

Abstract: The differential pressure measuring apparatus comprises a single chamber differential pressure sensor filled with a fluid and having two measuring capacitors whose capacitances vary in opposite senses in response to the differential pressure to be measured and in the same sense in response to the temperature said capacitances being transformed by means of associated capacitance measuring circuits into measurement signals which are supplied to a calculation circuit for calculating the temperature and the differential pressure. A temperature measuring means which comprises a temperature sensor mounted on the differential pressure sensor and a temperature measuring circuit connected to the temperature sensor measures directly the temperature of the single chamber differential pressure sensor.