| 摘要 |
PURPOSE:To prolong the maintenance period of ion measuring electrodes and to provide a margin in the time for dealing with abnormality in the event of the abnormality of the electrode by excluding the ion measuring electrode which is decided to be abnormal and continuing the measurement by the remaining electrodes. CONSTITUTION:The measuring signals by the electrodes 3a to 3d are read successively via a switching device 4 into a computing part 5. The average value of the measured values obtd. by the electrodes 3a to 3d are computed in the computing part 5. The average value is converted to a pH unit and is inputted to an instructing part 6 when there is not abnormality in the electrodes 3a to 3d. Process control is executed in accordance with the signals outputted from the instructing part 6. On the other hand, an alarm section 7 emits a primary maintenance alarm and the electrode decided to be abnormal is simultaneously excluded if any electrode is decided to be abnormal. The measurement by the remaining electrodes exclusive of the abnormal electrode is then continued and the process control is continued in accordance with the signal of the average value outputted from the instructing part 6. |
