8-2SectionPower Interruptions
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8-1-2 Operational Characteristics and Precautions in Using Flash
Memory
1, 2, 3... 1. If the contents of read-only DM Area words (DM 6200 to DM 6599) or the
User Setup Area (DM 6600 to DM 6655) are changed in the Customizable
Counter Unit and the power is turned OFF without switching from PRO-
GRAM to RUN or MONITOR mode, the changed contents in RAM will not be
written to flash memory and will be lost if power remains OFF longer than the
capacitor backup period. Perform the following steps to write changes to the
above words to flash memory.
• Change the Customizable Counter Unit to MONITOR or RUN mode.
• Cycle the power supply to the PC.
2. If the contents of read-only DM Area words (DM 6200 to DM 6599) or the
User Setup Area (DM 6600 to DM 6655) are changed in the Customizable
Counter Unit, it will take 1,200 ms longer to start operation compared to
starting when changes have not been made. You must confirm that the addi-
tional time to start operation will not adversely affect the system the first time
the PC is started after changing the contents of these words.
3. The cycle time will be increased by 1,200 ms and the user program area and
Unit Setup Area will be rewritten with interrupts disabled when changing to
RUN or MONITOR mode and the under the following conditions.
• Program changes for online editing
• Changes to read-only DM Area words (DM 6200 to DM 6599)
• Changes to the User Setup Area (DM 6600 to DM 6655)
CYCLE TIME OVER errors will not occur for these conditions. You must
confirm that the longer cycle time and slower I/O response time will not ad-
versely affect the system before performing any of the above operations.
8-2 Power Interruptions
8-2-1 Operation at Power Interruptions
The following processing is performed if Customizable Counter Unit power is in-
terrupted.
The following processing will be performed if the CPU Unit detects a power inter-
ruption in RUN or MONITOR mode.
1, 2, 3... 1. The Customizable Counter Unit will stop.
2. Contact outputs from the Customizable Counter Unit will be turned OFF.
The following processing will be performed for a momentary power interruption.
1, 2, 3... 1. The system will continue to run unconditionally if the power interruption (i.e.,
the period during which the voltage is less than 85% of the rated voltage)
lasts less than 10 ms.
2. A power interruption may or may not be detected for a power interruption
that lasts more than 10 ms but less than 25 ms, i.e., the system may contin-
ue or it may stop.
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