Hitachi, Ltd.

Kouji Saito

Masao Fukunaga

Tamio Ishihara

Yutaka Sakurai

An electromagnetic flow meter for industries includes a transducer and a signal processor provided separately from the transducer. The transducer having an exciting circuit, an amplifying and calculating part and a transmitting part outputs an analog flow rate signal and digital signals which are superimposed to the an analog flow rate signal to the signal processor. The analog signal sent to the signal processor is passed through the signal processor without receiving any signal processing and the digital signals are sent into the transducer or taken into the signal processor through alternating current coupling means. The data transmission is diagnosed by checking the conformity between the data stored in the signal sending part and the received data. Data set in a data setting part provided in the signal processor are sent to the transducer through a transmitting cable in which the flow rate data are also transmitted.

Electromagnetic flow meter

An ultrasonic Doppler flowmeter in which a received signal processing part includes a reference signal generator for generating a reference signal corresponding to the magnitude of a received signal, and a comparator for comparing the received signal with the reference signal. The reference signal varies in accordance with the magnitude of the received signal, and further may possess a hysteresis width corresponding to the output of the comparator. Therefore, a noise signal is effectively removed from the received signal at the comparator, and only a Doppler shift frequency is detected.

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Mito, Japan

Kouji Saito