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Power OFF Operation Section 10-3
The following processing will be performed if power drops only momentarily
(momentary power interruption).
1,2,3... 1. The system will continue to run unconditionally if the momentary power in-
terruption lasts less than 10 ms, i.e., the time it takes the minimum rated
voltage at 85% or less to return to 85% or higher is less than 10 ms.
Note When DC power supplies are used, less than 2 ms is required for the rated
voltage of a CJ1W-PD025 at 80% or less to return to 80% or higher or for the
rated voltage of a CJ1W-PD022 at 90% or less to return to 90% or higher.
2. A momentary power interruption that lasts more than 10 ms but less than
25 ms (when using a DC power supply, more than 2 ms but less than 5 ms
for CJ1W-PD025 and more than 2 ms but less than 10 ms for CJ1W-
PD022) is difficult to determine and a power interruption may or may not
be detected.
3. The system will stop unconditionally if the momentary power interruption
lasts more than 25 ms (when using a DC power supply, more than 5 ms for
CJ1W-PD025 and more than 10 ms for CJ1W-PD022).
Therefore, the time required to detect a power interruption is 10 to 25 ms
(when using a DC power supply, 2 to 5 ms for CJ1W-PD025 and 2 to 10 ms
for CJ1W-PD022) If operation stops under the conditions given in items 2 and
3 above, the timing used to stop operation (or the timing used to start execu-
tion of the Power OFF Interrupt Task) can be delayed by setting the Power
OFF Detection Delay Time (0 to 10 ms) in the PLC Setup. Operation, how-
ever, will always be stopped 10 ms after detecting a momentary power inter-
ruption regardless of the setting in the PLC Setup. The holding time for the
5-VDC outputs of CJ1W-PD022 Power Supply Units when a power interrup-
tion occurs is 1 ms, however, so bit 22515 (Power OFF Interrupt Task Disable
Bit) and bits 22500 to 22507 (Power OFF Detection Time (Power OFF Detec-
tion Delay Time) Bits) cannot be used.
Note The above timing chart shows an example when the power OFF detection
delay time is set to 0 ms.
0 to 10 ms
(PD025/PD022:
0 to 2 ms)
Time
10 to 25 ms
(PD025: 2 to 5 ms,
PD022: 2 to 10 ms)
25 ms and longer
(PD025: 5 ms, PD022: 10 ms)
10 ms 25 ms
Power supply
voltage
Power supply
voltage
Power supply
voltage
Momentary power
interruption not
detected and op-
eration continues.
85% of the rated voltage or less (DC power supply: 80% or less for PD025, 90% or less for PD022)
Operation will continue or
stop depending on
whether or not a
momentary power
interruption is detected.
Momentary power interruption detected
and operation stops.
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