Endress + Hauser Flowtec Ag

Other

Thomas Kung

Andre Spahlinger

Markus Rufenacht

A method for controlling coil current of a magneto inductive, flow measuring device with a first value representing an overvoltage Uand a second value representing a holding voltage U, wherein the first value is greater than the second value, characterized by steps as follows: setting a first switching point Ifor the electrical current level, up to which a coil should be supplied with the overvoltage U; applying an overvoltage Uuntil the electrical current level rises to the switching point IS set for the electrical current level; switching from the overvoltage Uto the holding voltage U, in order to hold the electrical current level at a constant electrical current end value I. Also intended is a magneto inductive, flow measuring device.

Method for controlling coil current of a magneto inductive, flow measuring device

A method for controlling excitation energy in a coil arrangement of a flow measuring device having an energy buffer system for storing energy and embodied as a two-conductor field device is provided for producing a magnetic field B passing through a medium as a function of the excitation energy. The wherein the flow measuring device has a plurality of operating states, between which it transfers and which describe an excitation current pulsed in a time interval. At least a first operating state is operated with a first power, in which the coil arrangement in a first period is excited with an excitation current with a first maximum electrical current level, wherein the period additionally has a first pulse pause, wherein the method is characterized by steps as follows: storing a fed-in excess power, which is beyond a minimum power for operating the device, for operating the coil arrangement during a period as a function of the supplied power in an energy buffer system; wherein an at least partial charging of the energy buffer system occurs in the first pulse pause and an at least partial discharging of the energy buffer system occurs during the excitation of the electrical current level; and changing into a second operating state, in which the coil arrangement is excited in a second period with an excitation current, wherein the second period has a second pulse pause, which is shorter than the first pulse pause.

Method for controlling excitation energy in a coil arrangement of a flow measuring device embodied as a two-conductor field device

A measuring electronics serves for ascertaining a potential difference (&#x394;&#x3c6;) between a first measuring electrode and a second measuring electrode. For such purpose, the measuring electronics comprises a reference electrode, an input circuit having two circuit inputs electrically connectable with the first, respectively second, measuring electrodes and two signal voltage outputs, a compensation circuit, a measuring and control circuit having two signal voltage inputs, two signal voltage inputs electrically and a compensation control output. The compensation circuit is adapted to provide on the first compensation voltage output a compensation voltage, namely an adjustable direct voltage referenced to the reference potential, and on the second compensation voltage output a compensation voltage, namely a direct voltage referenced to the reference potential. Additionally, the compensation circuit includes at least two operating modes selectable by means of a compensation control signal appliable on the control signal input, wherein in a first operating mode the compensation voltage is set at a predetermined voltage value, and in a second operating mode the compensation voltage is set at a predetermined voltage value. The measuring and control circuit, in turn, is adapted to provide on the compensation control output a compensation control signal for selecting one of the selectable operating modes of the compensation circuit.

Growing community of inventors

Basel, Switzerland

Thomas Kung