Chapter 5. Power Supply / CPU
5-6
2) Time-driven operation
In time driven interrupt operation method, operations are processed not repeatedly but at every preset interval. In the GM7U
series, interval time can be set between 0.001 to 4,294,967.29 sec. This operation is used to process operation with a
constant cycle.
3) Interrupt task operation
The existing PLC program can be interrupted if an operation is required to be urgently processed.
The signal which informs the CPU of the urgent conditions is called the interrupt signal. The GM7U CPU has
three kinds of interrupt operation methods. These are internal, external, and high speed counter interrupt signal me
thods.
5.3.2 Operation processing at momentary power failure
Momentary power failure occurs when the input voltage to the power supply falls below the rated voltage. If there
is momentary power failure under 10ms, the CPU maintains operation processing. If it exceeds 10ms, the CPU will stop
processing and all outputs will be turned off. When the power is restored, the operation will be executed again
automatically.
1) Momentary power failure under 10 ms
2) Momentary power failure exceeding 10 ms
REMARK
1) Momentary power failure?
The PLC defines power failure as a state when the voltage has been lowered over the allowable range. The power
failure with a short interval (several to tens ms) is called momentary power failure.
Momentary power failure
under 1Oms
Power
Input
Power failure exceedin
10m
y The operation is stopped.
y The operation is executed again when the
power is restored
y The operation is maintained.
Power
Input
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