Omron C200HE-CPU11 Installation Manual page 89

Wiring
Power Interruptions
This circuit prevents outputs MC1 and MC2 from ever both being ON at the same
time. Even if the PC is programmed improperly or malfunctions, the motor is pro-
tected.
A sequential circuit is built into the PC to handle power interruptions. This circuit
prevents malfunctions due to momentary power loss or voltage drops. A timing
diagram for the operation of this circuit is shown below.
The PC ignores all momentary power failures if the interruption lasts no longer
than 10 ms (no longer than 2 ms for a DC Power Supply). If the interruption lasts
between 10 and 25 ms (between 2 and 5 ms for a DC Power Supply), the inter-
ruption may or may not be detected. If the supply voltage drops below 85% of the
rated voltage for longer that 25 ms (less for the DC Power Supply), the PC will
stop operating and the external outputs will be automatically turned OFF.
Operation is resumed automatically when the voltage is restored to more than
85% of the rated value. The diagram below shows the timing of PC operation
and stopping during a power interruption. The time it takes to detect the power
failure is shorter when the power supply is DC. Also, the voltage value for which
the C200HX/HG/HE will stop due to a drop in the power supply voltage will be
lower than that for AC.
Power supply
Power failure detection signal
+5 V
CPU Unit operating voltage
Power supply reset
Power Power
interrupted restored
Time lapse until
detection
Section 3-2
77