Yokogawa Electric Corporation

Wandong Li

Masakazu Saito

Ikuhiko Ishikawa

Toru Shimura

Junichi Iwashita

Yuichi Kaneko

Daisuke Harigane

A field device according to one aspect of the present invention includes a sensor, an analog-digital converter configured to continuously convert detected signals output from the sensor to digital signals, and a calculator configured to convert the digital signals to process values. The calculator starts acquisition of the digital signals output from the analog-digital converter at a first point in time that is delayed by a processing time required for the conversion process of the analog-digital converter from a start point of a timing signal defining a sampling section of the detected signals, and finishes the acquisition of the digital signals output from the analog-digital converter at a second point in time that is delayed by the processing time from an end point of the timing signal.

Field device

An electromagnetic flowmeter applies a magnetic field, which is generated by excitation current, to a fluid to be measured flowing in a measurement tube, and measures a flow rate of the fluid to be measured on the basis of a detection signal to be generated from an electrode provided in the measurement tube. The electromagnetic flowmeter includes an excitation circuit configured to generate the excitation current having a positive excitation period, a negative excitation period and a non-excitation period, and a diagnosis unit configured to detect an abnormality based on characteristics of the fluid to be measured, on the basis of a level of the detection signal in a non-excitation stable period, which is a period in which a differential noise of detection signal to be generated in the non-excitation period converges.

Electromagnetic flowmeter

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Tokyo, Japan

Wandong Li