摘要:
A magnetoinductive flowmeter and a method for operating same utilizing a measuring tube through which flows an electrically conductive medium, as well as two measuring electrodes and a magnet with two field coils positioned parallel to each other on mutually opposite sides of the measuring tube. The measuring electrodes are so positioned that their connecting line extends along an essentially perpendicular vector relative to the direction of flow and to the magnetic field as well as through the cross-sectional center of the measuring tube. For normal flow-measuring operation, the two field coils are so energized that an essentially homogeneous magnetic field is generated, permeating the medium flowing through the measuring tube, while for determining the flow rate the voltage present between the two measuring electrodes is collected at one or both measuring electrodes and measured against a reference potential. The normal flow-measuring operation is intermittently interrupted and the two field coils are energized in a manner as to generate an inhomogeneous magnetic field that permeates the medium flowing through the measuring tube, and the voltage present between the two measuring electrodes is collected. This permits a diagnosis of the flowmeter.
摘要:
A method for operation of several adjacent magnetic-inductive flow meters, each of which has a measurement tube through which an electrically conductive medium flows, a magnetic field generating apparatus for permeating the medium with a magnetic field having a component perpendicular to the longitudinal axis of the measurement tube, and a measurement apparatus for measuring the voltage induced into the medium and for determining the flow rate from the induced voltage. Each flow meter has a control apparatus. In order to prevent variations of mutual influences on the flow rate measurements by the magnetic fields of adjacent flow meters, measured flow rate values from individual measurement processes and synchronous measurement processes are used to determine the mutual influences on the flow rate measurements, and influences that are free of variations are compensated by the magnetic fields of the adjacent flow meters being synchronized.
摘要:
The magnetoinductive flowmeter measures the flow volume of a medium traveling through a measuring tube, with a magnet that serves to generate a magnetic field permeating the measuring tube that has a magnetic-field component that extends perpendicular to the direction of flow. The flowmeter also includes a first measuring electrode and a second measuring electrode for collecting a voltage induced in the medium, a reference electrode, as well as a preamplifier to which the potentials collected by the two measuring electrodes are fed. A control circuit element is provided for controlling the common-mode input voltage of the preamplifier and/or the potential span of the dynamic range of the preamplifier in such fashion that the said common-mode input voltage of the preamplifier corresponds to approximately half the maximum output voltage of the preamplifier. This concept also permits the use of preamplifiers that operate with a low supply voltage such as 0/5 V. A measuring method is also disclosed.
摘要:
A method for operating a magnetoinductive flowmeter of the type including a measuring tube through which flows an electrically conductive medium, at least two electrodes that are in direct conductive contact with the medium, and at least one magnetic field coil that serves to generate a magnetic field which permeates at least part of the medium and in which a predefined current is impressed between two electrodes that are in wet contact with the flowing medium, the voltage present between the two electrodes or between one of the two electrodes and another electrode that is in wet contact with the flowing medium is measured, and a resistance value is derived from the ratio of the impressed current to the measured voltage. This permits the determination and read-out of the conductivity of the medium flowing through the measuring tube, which constitutes an added benefit for the user of the magnetoinductive flowmeter.
摘要:
A method for operating a magnetoinductive flowmeter of the type including a measuring tube through which flows an electrically conductive medium, at least two electrodes that are in direct conductive contact with the medium, and at least one magnetic field coil that serves to generate a magnetic field which permeates at least part of the medium and in which a predefined current is impressed between two electrodes that are in wet contact with the flowing medium, the voltage present between the two electrodes or between one of the two electrodes and another electrode that is in wet contact with the flowing medium is measured, and a resistance value is derived from the ratio of the impressed current to the measured voltage. This permits the determination and read-out of the conductivity of the medium flowing through the measuring tube, which constitutes an added benefit for the user of the magnetoinductive flowmeter.
摘要:
A magnetoinductive flowmeter and a method for operating same utilizing a measuring tube through which flows an electrically conductive medium, as well as two measuring electrodes and a magnet with two field coils positioned parallel to each other on mutually opposite sides of the measuring tube. The measuring electrodes are so positioned that their connecting line extends along an essentially perpendicular vector relative to the direction of flow and to the magnetic field as well as through the cross-sectional center of the measuring tube. For normal flow-measuring operation, the two field coils are so energized that an essentially homogeneous magnetic field is generated, permeating the medium flowing through the measuring tube, while for determining the flow rate the voltage present between the two measuring electrodes is collected at one or both measuring electrodes and measured against a reference potential. The normal flow-measuring operation is intermittently interrupted and the two field coils are energized in a manner as to generate an inhomogeneous magnetic field that permeates the medium flowing through the measuring tube, and the voltage present between the two measuring electrodes is collected. This permits a diagnosis of the flowmeter.
摘要:
A non-intrinsically safely supplied measurement device (1) with a connecting device (3) having an “increased safety” type of protection for connecting the measurement device (1) to a feed connection (2) in order to supply the measurement device (1) with electricity, an electronic device (4) which contains electronic components of the measurement device (1), a display device (8), a sensor (7) made with “increased safety” or “intrinsic safety” type of protection, and an output circuit (9) that is without at least the “intrinsic safety” type of protection. The electronic device (4) has an “encapsulation” type of protection, the display device (8) has an “intrinsic safety” type of protection and the display device (8), the sensor (7) and the output circuit (9) are connected to the electronic device (4) via connections having an “increased safety” type of protection.
摘要:
The magnetoinductive flowmeter measures the flow volume of a medium traveling through a measuring tube, with a magnet that serves to generate a magnetic field permeating the measuring tube that has a magnetic-field component that extends perpendicular to the direction of flow. The flowmeter also includes a first measuring electrode and a second measuring electrode for collecting a voltage induced in the medium, a reference electrode, as well as a preamplifier to which the potentials collected by the two measuring electrodes are fed. A control circuit element is provided for controlling the common-mode input voltage of the preamplifier and/or the potential span of the dynamic range of the preamplifier in such fashion that the said common-mode input voltage of the preamplifier corresponds to approximately half the maximum output voltage of the preamplifier. This concept also permits the use of preamplifiers that operate with a low supply voltage such as 0/5 V. A measuring method is also disclosed.
摘要:
A magnetically inductive flowmeter for flowing media, with a measuring tube, with a magnet for generating a magnetic field passing essentially perpendicular to the axis of the measuring tube and to the direction of the magnetic field, with at least two measuring electrodes arranged along a connecting line passing essentially perpendicular to the axis of the measuring tube and to the direction of the magnetic field, with a reference electrode and with a difference amplifier having a reference potential connection connected with the measuring electrodes via measuring electrode connections and serving for amplification of the measuring voltage present on the measuring electrodes. The magnetically inductive flowmeter has lower demands for the measures for producing a reference potential because the reference potential connection of the difference amplifier is connected only with the reference electrode and the reference electrode is connected only with the reference potential connection of the difference amplifier and because the difference amplifier is not connected with a potential equalization.
摘要:
An electric device features a two-wire interface which two-wire interface serves to feed electric power to the electric device and also to transmit a signal, with the maximum power drawn via the two-wire interface in normal operation being restricted to a predefined upper limit. The permissible maximum power consumption of the electric device is automatically and temporarily increased beyond the predefined upper limit when the electric device is switched into a special operational function mode. The length of time in which the electric device is in the special operational function mode can thus be reduced.