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Description of Operation Section 3-2
Continued and
stopped Loop
Controller operation
during momentary
power interruptions
The following information outlines whether or not Loop Controllers will con-
tinue or stop operation when a momentary power interruption has occurred in
the PLC (Power Supply Unit) power supply. The conditions are the same as
for CS-series CPU Units.
Operation conditions will change as indicated below when the momentary
power interruption to the PLC power supply voltage (85% or less of the rated
voltage) is of the following duration:
• Less than 0 to 10 ms for AC power supply or less than 0 to 2 ms for DC
power supply: Operation continues.
• Between 10 and 25 ms for AC power supply or between 2 and 5 ms for
DC power supply: Operation sometimes continues and sometimes stops.
• 25 ms or more for AC power supply or 5 ms or more for DC power supply:
Operation stops.
If the power interruption detection extension time (T) is set in the PLC Setup,
the time that operation will definitely continue after a power interruption can be
set to between 0 and (10+T). T can be set between 0 and 10 ms.
Operation conditions will change as indicated below when the momentary
power interruption to the PLC power supply voltage (85% or less of the rated
voltage) is of the following duration:
• Less than 0 to (10 +T) ms for AC power supply or less than 0 to (2 +T) ms
for DC power supply: Operation continues.
• Between (10+T) and (25+T) ms for AC power supply or between (2+T)
and (5 +T) ms for DC power supply: Operation sometimes continues and
sometimes stops.
• (25+T) ms or more for AC power supply or (5+T) ms or more for DC power
supply: Operation stops.
10 ms
25 ms
Power interruption
starts
Time
Power interruption time
where operation will
definitely continue: 10 ms
or less
Power interruption time where operation may
or may not continue:
10 ms or more and less than 25 ms
Operation may or may not
continue if power restored in
this time range.
Power interruption time where operation will definitely stop:
25 ms or more
Power interruption
time less than 10 ms
Operation continues.
Operation may or may not continue if
power restored in this time range.
Power interruption
time between 10 ms
and 25 ms
Operation may or may not continue.
Operation stops.
Power interruption time 25 ms or more
* For AC power supplies