Abstract: A method for operating a magnetic field generator for a magnetic-inductive flowmeter is disclosed. The method involves setting, at a first reversal time, a target current value as target current and a first target voltage value as target voltage. The first target voltage value is greater than a second target voltage value, and the second target voltage value as target voltage effects the control voltage value of a current regulator voltage in a steady state of the magnetic field generator. The method further involves determining a first switching time. The current between a first reversing time and the first switching time reaches the target current value. A current regulator voltage at the first switching time is greater than a minimum voltage value and less than a control voltage value. At the first switching time, the second target voltage value is then set as the target voltage.

Abstract: A method for determining conductivity of a medium includes: generating a signal with first and second frequencies; feeding the signal to first and second electrodes; determining a first voltage between the first and second electrodes, a first current through the medium for the first frequency, and a first impedance from the first voltage and first current; determining a second voltage between the first and second electrodes, a second current through the medium for the second frequency, and a second impedance from the second voltage and second current; determining and comparing phases of the first and second impedances; determining a medium resistance with a first formula when the first impedance phase is smaller than the second impedance phase; determining a medium resistance with a second formula when the first impedance phase is equal to or greater than the second impedance phase; and determining conductivity of the medium using the medium resistance.

Abstract: A magnetic-inductive flowmeter includes a measuring tube for carrying an electrically conductive medium, a magnetic field generator for generating a magnetic field passing through the medium, two electrodes for tapping a measuring voltage induced in the medium, a ground element electrically connected to the medium, and an evaluation unit. The electrodes are connected to the evaluation unit via electrode lines. The ground element is connected to the evaluation unit via a first ground line for potential equalization between the medium and a reference potential of the evaluation unit. The ground element is connected to the evaluation unit at least indirectly via a second ground line. The first and second ground lines are part of a monitoring circuit for monitoring the connection between the ground element and the evaluation unit. The evaluation unit is designed such that it monitors the connection between the ground element and the evaluation unit.

Abstract: A magnetic-inductive flowmeter and a method for operating the flowmeter are disclosed. The flowmeter has a measuring tube, a magnetic field generator, and a controller with first and second measuring terminals. A medium is made to flow through the measuring tube. The controller performs the following steps: generating and feeding an emission signal and receiving a receive signal caused by the emission signal at the first measuring terminal and second measuring terminal; determining an impedance with an impedance amount and an impedance phase using the emission signal and the receive signal; and signaling a short circuit if the impedance amount is smaller than a first limit impedance amount and the impedance phase is larger than a limit impedance phase.

Abstract: A magnetic-inductive flowmeter includes a tube, electrodes in contact with a medium in the tube, a magnetic field generator, an impedance signal generator, and a control device. A first signal path interconnects the impedance signal generator and a first electrode, and a second signal path interconnects the impedance signal generator and a second electrode. A first switch and first and third capacitors are connected such that, in a first state, only the first capacitor and, in a second state, only the third capacitor is in the first signal path. A second switch and second and fourth capacitors are connected such that, in a first state, only the second capacitor and, in a second state, only the fourth capacitor is in the second signal path. The control device sets the switches to the first state during a positive magnetic phase and to the second state during a negative magnetic phase.

Abstract: A magnetic-inductive flowmeter for determining the flow of a medium, having a measuring tube for guiding the medium and having two electrodes for tapping a measuring voltage induced in the medium, wherein the measuring tube has an inflow section, a measuring section and an outflow section arranged one after the other in the flow direction of the medium, the inflow section having a cross section which decreases in the flow direction, the measuring section having a constant cross section and being symmetrical with respect to a measuring section symmetry plane which runs parallel to the longitudinal axis of the measuring tube, and the outflow section having a cross section which increases in the flow direction and is formed at least partially asymmetrically with respect to the measuring section symmetry plane in order to increase measuring accuracy.

Abstract: A method for determining conductivity of a medium includes: generating a signal with first and second frequencies; feeding the signal to first and second electrodes; determining a first voltage between the first and second electrodes, a first current through the medium for the first frequency, and a first impedance from the first voltage and first current; determining a second voltage between the first and second electrodes, a second current through the medium for the second frequency, and a second impedance from the second voltage and second current; determining and comparing phases of the first and second impedances; determining a medium resistance with a first formula when the first impedance phase is smaller than the second impedance phase; determining a medium resistance with a second formula when the first impedance phase is equal to or greater than the second impedance phase; and determining conductivity of the medium using the medium resistance.

Abstract: A magnetic-inductive flowmeter for determining the flow of at least one medium, having first and second parallel measuring tubes for guiding the at least one medium, a magnetic field generating device for generating a magnetic field permeating the measuring tubes perpendicular to the flow direction of the at least one medium, first and second electrode pairs for respectively tapping a first and second measuring voltage induced in the medium, and an evaluation unit for evaluating the measuring voltages. Increased reliability in functioning of the flowmeter and the determined flow and flow difference values is achieved by the first and second electrode pairs being formed together by a first, second and third electrodes, the second electrode being both part of the first electrode pair and part of the second electrode pair and being arranged between the two measuring tubes. The electrodes are arranged perpendicular to the flow and magnetic field directions.

Abstract: A magnetic-inductive flowmeter includes a measuring tube for carrying an electrically conductive medium, a magnetic field generator for generating a magnetic field passing through the medium, two electrodes for tapping a measuring voltage induced in the medium, a ground element electrically connected to the medium, and an evaluation unit. The electrodes are connected to the evaluation unit via electrode lines. The ground element is connected to the evaluation unit via a first ground line for potential equalization between the medium and a reference potential of the evaluation unit. The ground element is connected to the evaluation unit at least indirectly via a second ground line. The first and second ground lines are part of a monitoring circuit for monitoring the connection between the ground element and the evaluation unit. The evaluation unit is designed such that it monitors the connection between the ground element and the evaluation unit.

Abstract: A magnetic-inductive flowmeter having a measuring tube for guiding a conductive medium, having a magnetic field generator for generating a magnetic field passing through the measuring tube at least partially perpendicular to the medium flow direction, electrodes for tapping a measuring voltage induced in the medium and a conductivity measuring device for determining the conductivity of the medium. The conductivity measuring device has a measuring circuit with the electrodes, a voltage source and a measuring unit. In operation, the voltage source generates a voltage and the measuring unit measures the actual electrode voltage applied between the electrodes. The control unit sets the actual electrode voltage to a predetermined constant setpoint value and the evaluation unit determines the electrode current flowing between the electrodes and calculates the conductivity value of the medium or a variable related to the conductivity using the determined electrode current and the actual electrode voltage.

Abstract: A method for configuring a field device for use in custody transfer and such a field device, wherein the field device has a computing unit and a storage, wherein parameters and/or functions are stored in the storage, and wherein the parameters and/or functions are at least partially configurable. A more flexible configuration of the field device used for custody transfer is achieved by at least two blocking groups being provided, wherein each blocking group comprises at least one parameter and/or at least one function of the field device, at least one blocking group is chosen and evaluated by the computing unit, and the computing unit blocking the parameters and/or functions contained in the chosen at least one blocking group against a subsequent change.

Abstract: A measuring device with at least one sensor and at least one transmitter housing, the transmitter housing having at least one terminal space and an electronics space adjacent to the terminal space and connected via a partition wall, wherein at least a first electronic device for connecting supply and/or I/O lines is arranged in the terminal space and at least a second electronic device is arranged in the electronics space with electronics for controlling the sensor. The first and second electronic devices are electrically conductively connected to one another via a contacting unit. The second electronic device has a terminal unit which is connected to the contacting unit via a plug connection hat has a joining direction. The terminal unit is fixedly arranged in the joining direction and to float perpendicular to the joining direction such that it adapts to the position of the contacting unit when connecting to the contacting unit.

Abstract: A method is described for secure communication with a field measuring device of process measuring technology. A plurality of scopes of rights, and a plurality of public keys of a corresponding plurality of asymmetrical key pairs, are stored in the field measuring device. Each public key is assigned a scope of rights, and at least one private key of the corresponding plurality of asymmetric key pairs is stored in an external communicator. Upon establishing contact of the external communicator with the field measuring device, the external communicator identifies itself by a public-key authentication with the stored private key to the field measuring device. The field measuring device authenticates the external communicator using a suitable public key stored in the field measuring device. The field measuring device then opens an operating session in which the external communicator is granted access to the information technology content of the field measuring device.

Abstract: A device for receiving an electronics assembly having a closed housing with a housing wall, at least one electronic component, a holder and a fan with a fan housing, wherein the electronic component, the holder and the fan are arranged within the housing, and the fan is arranged in the holder. To provide a device for receiving an electronics assembly that enables an alternative cooling of the electronics assembly in a closed housing is achieved in that the fan is designed as a revolving blade fan and by the fact that the fan generates a continuous air flow for cooling the electronic unit during operation.

Abstract: A magnetic-inductive flowmeter having a measuring tube for guiding a conductive medium, having a magnetic field generator for generating a magnetic field passing through the measuring tube at least partially perpendicular to the medium flow direction, electrodes for tapping a measuring voltage induced in the medium and a conductivity measuring device for determining the conductivity of the medium. The conductivity measuring device has a measuring circuit with the electrodes, a voltage source and a measuring unit. In operation, the voltage source generates a voltage and the measuring unit measures the actual electrode voltage applied between the electrodes. The control unit sets the actual electrode voltage to a predetermined constant setpoint value and the evaluation unit determines the electrode current flowing between the electrodes and calculates the conductivity value of the medium or a variable related to the conductivity using the determined electrode current and the actual electrode voltage.

Abstract: A field measuring device includes a sensor, a measuring transducer, and interface electronics. The interface electronics include a measuring and control device, and first and second terminals for connecting an external electrical device. A current controller and a current measuring device are connected in series in a terminal current path between the first and second terminals. The interface electronics has a voltage source that can be switched on in the terminal current path and disconnected from the terminal current path, so that the voltage source can drive a current in the terminal current path in the switched-on state and in the case of a connected external electrical device. The measuring and control device actuates and reads the current controller, the current measuring device, and the voltage source such that a current signal is output or input via the first and second terminals when an external device is connected.

Abstract: A magnetic-inductive flowmeter and method in which a control circuit and/or evaluation circuit is designed/operated in such a manner that a measuring voltage tapped or tappable by measuring electrodes for flow measurement are evaluated only during a flow measuring time that is less than half the duration of the period of generation of the magnetic field and that the control circuit is designed/operated in such a manner that the measuring electrodes are impinged with conductivity measuring signals only during a conductivity measuring time that lies outside the flow measuring time.

Abstract: A magnetic-inductive flowmeter for measuring the flow of a conductive medium having a measuring tube, a magnetic field generator, a magnetic circuit device for guiding the measuring magnetic field, electrodes for detecting a flow-dependent electrical measuring voltage when the conductive medium flows through the measuring tube, and an electronic control and evaluation unit, and a method for operating the magnetic-inductive flowmeter. To make the magnetic-inductive flowmeter which smaller and cheaper, a sensor for detecting a physical disturbance variable acting on the magnetic circuit device is arranged on the magnetic circuit device, wherein the measuring magnetic field is influenced by the physical disturbance variable and wherein the control and evaluation unit is designed such that it detects and signals an exceeding or falling below of a pre-definable limit value of the physical disturbance variable and/or performs a correction of the effect of the physical disturbance variable on the flow measurement.

Abstract: A flowmeter for use in custody transfer, having a housing, at last one evaluation unit arranged in the housing and having an interface arranged in the housing for communication with an external control unit that can be written with data via the interface. Inadmissible influencing of the evaluation unit is prevented by at least two write protection sensor elements being arranged in the housing, by the outside of the housing having a receptacle for at least one write protection influencing element that sets the write protection sensor elements into a write protection state when inserted in the receptacle, and by the write protection state of the write protection sensor elements being detected by the evaluation unit. In detecting the write protection state of at least one of the write protection sensor elements by the evaluation unit, writing the evaluation unit with data via the interface is at least partially inhibited.

Abstract: A field measuring device includes a sensor, a measuring transducer, and interface electronics. The interface electronics include a measuring and control device, and first and second terminals for connecting an external electrical device. A current controller and a current measuring device are connected in series in a terminal current path between the first and second terminals. The interface electronics has a voltage source that can be switched on in the terminal current path and disconnected from the terminal current path, so that the voltage source can drive a current in the terminal current path in the switched-on state and in the case of a connected external electrical device. The measuring and control device actuates and reads the current controller, the current measuring device, and the voltage source such that a current signal is output or input via the first and second terminals when an external device is connected.