STANDARD SIGNAL GENERATOR

摘要

To realize a stable operation and the suppression of heat generation in the case where an excitation current supplied from a converter is used to generate a power source voltage, a standard signal generator is provided. The standard signal generator includes an input circuit that includes: a rectification circuit that rectifies an excitation current; a resistor that is provided between a power source voltage output terminal for supplying a power source voltage and an output terminal of the rectification circuit; an amplification circuit that outputs an output voltage obtained by amplifying a voltage across both ends of the resistor; and a constant voltage circuit that performs control such that the power source voltage is constant. A power source voltage switch switches the power source voltage with the constant voltage circuit being controlled in accordance with the result of a comparison between the output voltage and a prescribed threshold value.

主权项

1. A standard signal generator that generates a reference flow-rate signal for calibrating an electromagnetic flowmeter, the standard signal generator comprising:
an input circuit that receives an excitation current from a converter of the electromagnetic flowmeter; a control unit configured to generate the reference flow-rate signal synchronized with the excitation current; and a power source voltage switch, wherein the input circuit comprises:
a first rectification circuit configured to rectify the excitation current;a first resistor that is provided between a power source voltage output terminal and configured to supply a power source voltage used by the standard signal generator and an output terminal of the first rectification circuit;an amplification circuit configured to output a first output voltage obtained by amplifying a voltage across both ends of the first resistor thereof; anda constant voltage circuit configured to perform control such that the power source voltage that is output from the power source voltage output terminal is constant,wherein the power source voltage switch is configured to switch the power source voltage with the constant voltage circuit being controlled in accordance with a result of a comparison between the first output voltage and a prescribed first threshold value.