PLANT PROTECTION INSTRUMENTATION DEVICE

摘要

PROBLEM TO BE SOLVED: To avoid much trouble and time which cause to increase product cost because of needs of verification for ensuring reliability of software and the work for intactness confirmation in the case an instrumentation circuit of comparing process signal and set value is constituted of a microprocessor in a plant protection instrumentation device, and avoid increase in pattern number of digital input in the case of function confirmation test when using a hardware device for process signal only. SOLUTION: The instrumentation circuit is constituted of a logic integrated circuit of hardware electrically independent of a plurality of different process signals. The instrumentation circuit is multi-plexed for a single process signal. The output signal from the multi-plexed instrumentation circuit is logically decided using a majority decision circuit and operation signal is output. COPYRIGHT: (C)2004,JPO