Electromagnetic flowmeter and self-diagnosing method of exciting circuit unit thereof
US9651411B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 21, 2012 |
| Grant date | May 16, 2017 |
| Priority date | — |
| Expiry date | Feb 14, 2036 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F15/00
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An electromagnetic flowmeter using a square wave excitation method includes a differential amplifier which outputs a detection signal; an analog-digital converter which converts the detection signal into a digital detection signal; a timing control circuit which generates a sampling signal for sampling the digital detection signal; an calculation unit which executes a flow rate calculation process and a abnormality judging process at a same time. The flow rate calculation process acquires a flow velocity output signal by sampling the digital detection signal in a flat portion in a positive/negative excitation section. The abnormality judging process acquires a differential output signal by sampling the digital detection signal in a rising/falling portion in the positive/negative excitation section, and obtains a differential noise from the flow velocity output signal and a differential output signal, and judges abnormality of the exciting current by comparing a differential noise with a detection threshold level.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.