| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a protective control apparatus which can suppress heat generation in the components of a logic input circuit to cope with a wide range of logic signals different in a rated voltage. <P>SOLUTION: An analog conversion circuit 12 converts a current and voltage input from a power system through an input transformer 11 into an analog signal, and an A/D converting circuit 13 converts the converted analog signal into a predetermined digital signal. A logic input circuit 15 takes in an external voltage logic signal having a predetermined operation condition and an output condition, and a calculation processing circuit 14 performs a predetermined protective control calculation based on the digital signal in the A/D conversion circuit and the logic signal in the logic input circuit. A logic input control circuit 18 intermittently operates the logic input circuit at the timing for taking in the voltage logic signal from the outside in accordance with the command of the calculation processing circuit 14, while a power supply circuit 19 supplies a control power supply voltage to each circuit so that the control voltage becomes equal to the voltage of the external logic signal of the logic input circuit 15. <P>COPYRIGHT: (C)2011,JPO&INPIT |
