17
Structure and Operation Section 1-3
2. Undetermined additional time
Power interruptions only slightly longer than the minimum power interrup-
tion time may not be detected.
Note If the power supply voltage fluctuates around 85% of the PC’s rated voltage,
PC operation may stop and restart repeatedly. When repeated stopping and
starting will cause problems with the controlled system, set up a protective cir-
cuit such as a circuit that shuts OFF the power supply to sensitive equipment
until the power supply voltage returns to the rated value.
85% of rated voltage
Program execution
CPU reset signal
Detection of
power interruption
Executing
Stopped
1. Minimum time 2. Additional
time
CPU Unit operation will
continue if voltage is
restored in this region.
CPU Unit operation may
continue if voltage is
restored in this region.