Flowmeter fault detection
AssigneeABB AB
InventorRay Keech
Life of this patent
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Abstract
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: first and second inputs for connection to potential sensing electrodes positioned to measure a potential difference across the fluid which potential is representative of flow; differential amplifier means coupled to the first and second inputs for producing an output signal indicative of said potential difference across the fluid as a measure of flow; characterised by at least one voltage sensing means for sensing a voltage of at least one of the first and second inputs relative to a ground reference; and fault detecting means for detecting a potential fault if the voltage is outside a predetermined range.
Claims33
Flowmeter sensing circuitry, comprising:
- first and second inputs for connection to potential sensing electrodes positioned to measure a potential difference across the fluid which potential is representative of flow;
- differential amplifier means coupled to the first and second inputs for producing an output signal indicative of said potential difference across the fluid as a measure of flow;
- characterised by
- at least one voltage sensing means for sensing a voltage of at least one of the first and second inputs relative to a ground reference;
- and
- fault detecting means for detecting a potential fault if the voltage is outside a predetermined range.
An analysis tool for detecting a potential fault in a flowmeter installation comprising means for receiving an input of the voltage of at least one potential sensing electrode of the flowmeter with respect to ground over a period of time and means for identifying from said input excursions of said voltage outside a predetermined range.
A method of detecting a potential fault in flowmeter sensing circuitry comprising first and second inputs for connection to potential sensing electrodes positioned to measure a potential difference across the fluid which potential is representative of flow and differential amplifier means coupled to the first and second inputs for producing an output signal indicative of said potential difference across the fluid as a measure of flow, the method comprising:
- sensing a voltage of at least one of the first and second inputs relative to a ground reference;
- and
- detecting a potential fault by detecting whether the voltage is outside a predetermined range.
Use of a measure of voltage with respect to a ground reference voltage of an input of a differential amplifier of flowmeter sensing circuitry to detect a potential fault condition.
Dependencies are inferred from the claim text.