| 摘要 |
PROBLEM TO BE SOLVED: To suppress unnecessary heat generation and power consumption of an input circuit of a protection controller. SOLUTION: The input circuit 2 which takes the on operation of a contact 1 as the secondary-side current of a photocoupler 3 is provided with a parallel circuit of a capacitor 4 and a resistor 5 for making the photocoupler 3 sense and maintain the on operation between the contact 1 and the primary side of the photocoupler 3. The values of the capacitor 4 and resistance 5 are so set that the maximum current in the beginning of the on operation of the contact 1 is about 30 mA and the minimum current at settlement time is about 2 mA. |
