Abb Inc.

Abb Instrumentation Limited, Ltd

Ray Keech

David Lincoln

Peter Asquith

Phillip Stafford

Neil Coleman

Simon Draper

A method measures electrical impedance of electromagnetic flowmeter sensing electrodes includes intermittently injecting an impedance measurement signal to at least one sensing electrode while a coil excitation drive signal is applied to flowmeter field generating coils. During a first interval, when the coil excitation drive signal is applied to the coils and the impedance measurement signal is injected to a sensing electrode, a first measurement signal is obtained. The first measurement signal includes an electromagnetically induced flow measurement signal and an electrode impedance measurement signal. During a second interval, when the coil excitation drive signal is applied to the coils but the impedance measurement signal is not injected to the sensing electrodes, a second measurement signal is obtained that includes an electromagnetically induced flow measurement signal. The first and second measurement signals combine into an output signal including the electrode impedance measurement signal without the electromagnetically induced flow measurement signal.

Method and apparatus for electrode impedance measurement

A method and apparatus are for processing a periodic data-carrying signal to reduce periodic interference at either of a first fundamental frequency or a second fundamental frequency, the second fundamental frequency being different from the first fundamental frequency. The periodic data-carrying signal is derived from an excitation signal having an excitation frequency, the excitation frequency being a sub-multiple of the first fundamental frequency. The data-carrying signal is subjected to both a comb filter to reject interference at the first fundamental frequency, and an averaging/integrating filter to reject interference at the second fundamental frequency. A comb filter delay period is related to the first fundamental frequency and the averaging/integrating filter averages or integrates over a period related to the second fundamental frequency.

Method and apparatus for interference reduction

Methods and apparatus are for storing and retrieving data related to the installation, service, repair or performance of an industrial flow meter or other measurement instrument. Methods and apparatus are also for other processes associated with measurement instruments.

Methods and apparatus relating to measurement instruments

An insert for an electromagnetic flow meter is disclosed. The insert is arranged to be positioned within a flow conduit having a flow conduit cross-section to define a flow path for fluid, wherein the insert comprises an inlet, a measuring section with a measuring cross-section different from the flow conduit cross-section and having at least two substantially parallel sides over at least part of its length, and an outlet.

Electromagnetic flow meter insert

A meter for monitoring consumption of a resource, such as water or other fluids, and corresponding methods of configuring and operating the meter are disclosed. The meter includes processing and memory devices for determining and storing a supplier measure of consumption of the resource and a communication link for enabling a supplier to access the stored supplier measure. The supplier access is controlled by a first access control device, which prevents unauthorized access to the stored data. The meter further includes a consumer data memory for storing consumer data including a consumer measure of consumption and second access control device. The second access control device enables a consumer to access the stored consumer data without permitting the consumer to modify the stored supplier measure of consumption.

Consumption meter

A previously unidentified problem of clipping in the input stages of flowmeter sensing circuitry has been identified and addressed. A solution is provided by flowmeter sensing circuitry, comprising:

Flowmeter fault detection

An improvement over conventional electromagnetic flowmeters which signal a measure of flow rate by controlling the current in a current signalling loop (also known as a sensing loop) and in which power for the flowmeter is derived from the current in the signalling/sensing loop. Conventional electromagnetic flowmeters use a standard current range (typically 4-20 mA), in which zero flow is indicated by controlling the current in the loop to a minimum predeterimened value and maximum flow is indicated by controlling the current to a maximum predetermined value. In the improved flowmeter of the invention, minimum flow is signalled by maximum current in the signalling/sensing loop and maximum flow is signalled by minimum current. This has been found to enable improved accuracy to be obtained at low flow rates without requiring complex flowmeter circuitry.

Electromagnetic flowmeter deriving power from signalling loop current

In an electromagnetic flowmeter, the conventional derivation of flow velocity is corrected or replaced by an alternative calculation to take into account estimated non-linear dependence of field strength produced by the coil with applied coil current. This can be used to enable more accurate measurement, over a wider range of coil current. The improved accuracy allows the coil current to be adjusted to optimise power consumption; the adjustment of coil current in this manner is another aspect of the invention.

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Stonehouse, United Kingdom

Ray Keech