When A Plc Is Reoperated After Stored With The Battery Over The Battery Life - Mitsubishi Q2ACPU User Manual

21. MAINTENANCE AND INSPECTION

21.6 When a PLC is Reoperated After Stored with the Battery Over the Battery Life

If a battery exceeded its guaranteed life is stored and reoperated, the memory contents of
CPU module and memory card may be undefined.
Therefore, when resuming the operation, clear the CPU module memory and format the
memory in the CPU module by peripheral device.
Afeter doing so, write the memory contents backed up before saving to each memory.
The relationship between the backed-up memory and the batteries is explained below.
Memory
Built-in RAM
CPU module
Device*
SRAM type
Memory card
SRAM + E2PROM
type
Before resuming the operation, clear/format the memory for which a battery is backed up
in the table above with a peripheral device.
For memory clear/format operations, refer to the following manuals.
• Type SW
• GX Developer Operating Manual
SRAM
2
E PROM
*As for device memory, also clear the latch range.
IVD-GPPQ GPP Software package Operating Manual (Online)
POINT
(1) Make sure to back up each memory contents before storing a PLC.
(2) When a PLC 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.
RAM data in built-in RAM
Breakdown history
Latch data (Latch relay (L), latch setting range device set in a parameter),
special relay SM900 to SM999, special register SD900 to SD999)
Sampling trace data
A6BAT installed in a CPU module
– (Battery back up is not required.)
:
Battery is backed up.
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Battery
Battery incorporates a memory card
: Battey is not backed up.