| 摘要 |
PURPOSE:To prevent a malfunction of a sequence controller regardless of a fault of the power supply, by using a relay to the control of load of a device to be controlled and obtaining the driving power supply of the relay from the input of a stabilized power supply for memory. CONSTITUTION:The power supply input E1 is connected to a stabilized power supply REG as well as to the coils of the relays REL0-RELn. Then the power supply is applied, the input E1 increases gradually. The output voltage of the REG is stabilized when the input E1 reaches about 50% its rated voltage. Then +5V is applied to a memory M as the power supply voltage, and the memory M can have a normal operation. Thereafter, the E1 increases continuously up to about 70% its rated voltage. Thus the relays REL0-RELn become active. In other words, these relays never operate before the memory M starts a correct operation. The loads Z1-Zn are never controlled by the erroneous data output of the memory M due to the insufficient voltage of the power supply although a start switch SW is turned on. The malfunction is also completely prevented when the voltage drops. |
