| 摘要 |
<P>PROBLEM TO BE SOLVED: To eliminate the deficiency wherein, when starting measurement of a test piece, troublesome operation is required as a prestage, for calibrating the gain of an instrumentation amplifier each time, when turning on a power supply of a material testing machine. Ž<P>SOLUTION: A cable unit CU is equipped with impedances R<SB>3</SB>, C<SB>3</SB>for calibration for supplying electrically a virtual displacement output, without applying actual displacement to a differential transformer LVDT. An ROM in the cable unit CU stores data for electric calibration adapted to the differential transformer LVDT. When calibrating the gain of the instrumentation amplifier 10, a switch S1 is switched on, and the gain of the instrumentation amplifier 10 is adjusted so that measured values stored in the ROM can be acquired. Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž
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