1-3SectionStructure and Operation
15
1-3-4 PC Operation at Startup
The time required for startup initialization depends on several factors, such as
the operating conditions (including power supply voltage, system configuration,
and ambient temperature) and the program contents.
Power OFF Operation Minimum Power Supply Voltage
The PC will stop and all outputs will be turned OFF if the power supply voltage
falls below 85% of the rated value.
Momentary Power Interruption
A power interruption will not be detected and CPU Board operation will continue
if the power interruption lasts less than 2 ms for a DC power supply.
A power interruption may or may not be detected for power interruptions some-
what longer than 2 ms for a DC power supply.
When a power interruption is detected, the CPU Board will stop operating and all
outputs will be turned OFF.
Automatic Reset
Operation will restart automatically when the power supply voltage is restored to
more than 85% of the rated voltage.
Timing Chart of Power OFF Operation
The power interruption detection time is the time required for a power interrup-
tion to be detected after the power supply voltage drops below 85% of the rated
value.
1, 2, 3... 1. Minimum power interruption detection time
Power interruptions that are shorter than 2 ms will not be detected.
2. Undetermined additional time
Power interruptions only slightly longer than the minimum power interrup-
tion time may not be detected.
85% of rated voltage
Program execution
CPU reset signal
Detection of
power interruption
Executing Stopped
1. Minimum time 2. Additional
time
CPU Board operation
will continue if voltage is
restored in this region.
CPU Board operation
may continue if voltage
is restored in this region.
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 circuit such
as a circuit that shuts off the power supply to sensitive equipment until the power
supply voltage returns to the rated value.
Time Required for
Initialization