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Appendices
Power OFF Timing Chart
Power supply
voltage: 85%
Power OFF
detected signal
Program execution
status
CPU Unit reset signal
Power OFF Detection Time:
Power Holding Time:
Description of Operation
The power interruption will be detected if the 100 to 240 VAC power supply falls below 85% of the
minimum rated voltage for the power OFF detection time (10 ms minimum for AC power supply and
2ms minimum for DC power supply, not fixed).
The CPU reset signal will turn ON and the CPU Unit will be reset immediately.
Instruction Execution for Power Interruptions
The power OFF detection time of CP1E CPU Units is 10 ms minimum for AC power supply and 2ms
minimum for DC power supply. If the power interruption is detected when operating in RUN or MONI-
TOR mode, the instruction currently being executed will be stopped and then the CPU Unit will be reset.
Malfunction Countermeasures
If only a couple of Expansion I/O Units or Expansion Units are connected to the CPU Unit resulting in a
light power supply circuit load and a small current consumption, the time required by the CPU Unit to
detect a power interruption will be longer. For this reason, inputs may be incorrectly identified as being
OFF if external power supply used for an input turns OFF before the power interruption is detected. If
an external NC contact input is used or the ladder program counts the number of ON to OFF transitions,
a malfunction may occur if the external power supply turns OFF.
A-86
Operation always stopped at this point
Holding time for 5 V internal
power supply after power OFF
detection: 1 ms
Power OFF detection
Power OFF Detection Time
AC: 10ms
DC: 2ms
Cyclic task or interrupt task
The time from when the power supply voltage drops to 85% or less the rated voltage until the
power interruption is detected.
The maximum amount of time (fixed at 1 ms) that 5 V will be held internally after power shuts
OFF.
Stop
CP1E CPU Unit Software User's Manual(W480)
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