Accurate and responsive weighing apparatus with drift compensation

摘要

In order to increase both the weighing accuracy and the weighing speed of a weighing apparatus, a deltaxsigma analog-to-digital converter (4) having a cut-off frequency higher than that of an analog filter (3) is connected with the output of the analog filter (3). Also, in order to perform a quick drift correction of an amplifier (2), the analog filter (3) is selectively switchable so as to perform a filtering function during a weighing mode and to perform a buffering function during a correction mode correcting means (52) is provided for storing the digital signal from the deltaxsigma analog-to-digital converter (4) as a drift signal (df) during the correction mode and for providing a corrected digital weight signal (d2) by subtracting the drift signal (dr) from the digital weight signal (d1) obtained from the deltaxsigma-type analog-to-digital converter (4) during the weighing mode.