| 摘要 |
PURPOSE:To make it possible to perform calibration tests in any exciting method, by inputting a reference voltage for calibration corresponding to the direction of an exciting current for the converter of an electromagnetic flowmeter into the converter. CONSTITUTION:Input terminals 50a and 50b are connected to the output terminals of an exciting current for the converter of an electromagnetic flowmeter. Output terminals 90a-90c are connected to the input terminals of the detected signal of the converter. Then the exciting current having both polarities is supplied to the terminals 50a and 50b from the converter. When the directions of the exciting current are X and Y, the logical values of operation amplifiers 52 and 54 becomes a ''1''. When the logical value of the amplifier 1 becomes a ''1'', a switch 66 is closed and a calibrating voltage is generated across a resistor 86 by a DC power source 82. The voltage is applied to the input terminals of the detected signal of the converter through the terminals 90a and 90c. When the logic value of the amplifier 54 becomes a ''1'', a switch 68 is closed and a calibrating voltage in reverse plurality is generated across a resistor 88. The voltage is applied to the input terminals of the detected voltage of the converter through the terminals 90b and 90c. Since the calibrating signal voltages are given to the input terminals of the detected signal of the converter at the same timing as the actual signal of the detector, the calibration test of the converter can be performed. |
