公开(公告)号：JPH07181161A

公开(公告)日：1995-07-21

申请号：JP34658793

申请日：1993-12-22

Applicant: TOA ELECTRONICS

Inventor： SHINNO TETSUHISA ,  OGAWA NOBUHIRO ,  UENO TADAAKI ,  KOBAYASHI KANEO

IPC: G01N27/26

Abstract: PURPOSE:To obtain the concentration meter which is operated stably in an automatic operation and whose reliability is enhanced by a method wherein the difference between an electromotive force in a calibrating operation at a low concentration and that in a previous calibrating operation, a generated electromotive force per pX in a calibrating operation, the stability of an electromotive force in a calibrating operation at a highconcentration and the responsivity in the calibrating operation at the high concentration are established as a rule and a fuzzy operation is performed. CONSTITUTION:Electric signals from individual electrodes 2, 4, 6 in a measuring cell 8 are amplified by an analog amplifier, they are converted into digital signals by an A/D converter 100, and the digital signals are input to a control part 102 provided with a microcomputer. The control part 102 controls a driver circuit 104, and it performs a fuzzy operation in order to obtain the sensitivity of the electrodes, the date and time of a calibrating operation and the like. Then, four elements, i.e., the difference between an electromotive force in a calibrating operation at a low concentration and that in a previous calibrating operation, a generated electromotive force per pX in a calibrating operation, the stability of an electromotive force in a calibrating operation at a high concentration and the responsivity of the calibrating operation at the high concentration, are established as a rule, a fuzzy operation is performed, the present sensitivity of the electrodes is found, a period of time during which reliable data can be measured on the basis of the sensitivity is estimated, and the date and time of a next calibrating operation is set.