
4. AnSHCPU MODULE
4 - 6
MELSEC-A
4.1.3
Operation processing when a momentary power interruption occurs
When voltage supplied to the power supply module is below the specified range,
the AnSHCPU detects a momentary power interruption.
When the AnSHCPU detects a momentary power interruption, the following
operations are executed :
(1)
Momentary power interruption within 20 msec
(a)
Program processing is stopped and the output is retained.
(b)
Program processing is resumed when the power is restored.
(c)
The watchdog timer (WDT) continues counting even while the operation
is stopped.
For example, if a momentary power interruption of 20 msec occurs when
the scan time is 190 msec, a watchdog timer error (200 msec) occurs.
(2)
Momentary power interruption over 20 msec
The AnSHCPU is reset and returns to the initial start status. The necessary
operations are the same as when the CPU power is turned ON or when the
CPU is reset.
Momentary power
interruption occurrence
Power supply
END 0
The AnSHCPU stops operating.
END 0
END
Fig. 4.2 Operation processing when a momentary power interruption occurs
Содержание A1SH
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