| 摘要 |
PURPOSE:To prevent malfunctions and inoperativeness due to aged components and obtain accurate tripping characteristic with errors due to aged components being self-corrected CONSTITUTION:A microprocessor 154 functions to periodically switch an input changing circuit 151 to the zero potential side (GND side), to monitor error component (offset value) due to aged components, contained in the output of an A/D conversion circuit 153, and to determine whether the error component exceeds a specified range. In addition the microprocessor 154 subtracts the error component (offset value) from the actual output of the A/D conversion circuit 153 for correction. |
