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10. MAINTENANCE AND INSPECTION
10.4 Operating a CPU Module After Being Stored Over the Battery Life
When a CPU module is operated again after being stored over the battery life, data in the 
CPU module (built-in RAM, device data) and a memory card may be undefined.
Before operating the CPU module again, clear data in the built-in RAM using a peripheral 
(PC memory clear operation) and also clear data using the RESET/L.CLR switch of the 
CPU module (latch clear operation).
After all data are cleared, write the backed-up data in the CPU module or the memory 
card.
The relationship between the backed-up memory and the batteries is explained below.
: Battery is backed up.  : Battery is not backed up.
If data in the memory are backed up with the battery (refer to the table above), clear and 
format the memory using a peripheral before operating the CPU module.
For memory clear/format operations, refer to the following manuals.
GX Developer Operating Manual
Type A6GPP/A6PHP Operating Manual
Type SW IVD-GPPA Operating Manual
The relationship between the backed-up memory and the batteries
Memory
Battery
Battery of the QCPU 
Module
Battery Incorporated in a 
Memory Card
CPU module
Built-in RAM
Built-in ROM – (Battery back up is not required.)
Device memory
Memory card SRAM card
POINT
(1) Make sure to back up each memory contents before storing a programmable 
controller.
(2)  When a programmable controller power supply is on or CPU module reset is 
cancelled, a CPU module reviews the status of data below, and initializes all 
the data if detecting an error.
 • Latch data (latch relay (L), devices in latch setting range set in the 
parameter)
 • Sampling trace data
 • Status latch data
 • Special relay M9102 (SFC program continue start)