Chapter 5 CPU Module
5-
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2) Time driven interrupt operation method
In time driven interrupt operation method, operations are processed not repeatedly but at every pre-set interval. Interval, in the
MK80S series, can be set to between 0.001 to 6 sec. This operation is used to process operation with a constant cycle.
3) Event driven interrupt operation method
If a situation occurs which is requested to be urgently processed during execution of a PLC program, this operation method
processes immediately the operation, which corresponds to interrupt program. The signal, which informs the CPU of those
urgent conditions is called interrupt signal. The K7 CPU has two kind of interrupt operation methods, which are internal and
external interrupt signal methods.
5.2.2 Operation processing at momentary power failure occurrence
The CPU detects any momentary power failure when the input line voltage to the power supply falls down below the defined value.
When the CPU detects any momentary power failure, the following operations will be executed:
1) Momentary power failure within 20 ms
2) Momentary power failure exceeding 20 ms
REMARK
1) Momentary power failure
The PLC defining power failure is a state that the voltage of power has been lowered outside the allowable
variation range of it. The momentary power failure is a power failure of short interval (several to tens ms).
Input power
Momentary power failure
exceeding 2Oms
(1) The operation processing is stopped with the output retained.
(2) The operation processing is resumed when normal status is restored.
(3) The output voltage of the power supply retains the defined value.
(4) The watchdog timer (WDT) keeps timing and interrupt timing normally while the
operations is at a stop.
Input power
Momentary power failure
exceeding 2Oms
The re-start processing is executed as the power is applied.
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