| 摘要 |
PURPOSE:To dispense with the offset adjustment and gain adjustment of an A/p converter, which need to be done in a conventional art, by determining a full-scale value from the error of the A/p converter before the input of monitoring data into a processing unit so as to obtain precise monitoring data. CONSTITUTION:A switch circuit 3 for the detection of correcting data is put in a third mode, the input signal to an analog/pulse converter 4 is made zero and a count signal from a counter circuit 8 is entered so that a processing unit calculates the offset error of the analog/pulse converter 4. The switch circuit 3 is put in a second mode, the input signal to the analog/pulse converter 4 is set at a reference value and the count signal from the counter circuit 8 is entered so that the processing unit calculates the gain error of the analog/ pulse converter 4. After that, the switch circuit 3 is put in a first mode, a monitoring analog signal is applied to the input terminal of the analog/pulse converter 4 and the count signal from the counter circuit 8 is entered. As a result, precise monitoring data can be calculated on the basis of the offset error and the gain error, and correction work for obtaining the precise monitoring data is not needed.
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