3 CPU Unit Operation
3-6
CP1E CPU Unit Software User’s Manual(W480)
Ladder programs and the PLC Setup are automatically backed up to and restored from the built-in
EEPROM backup memory.
Backing Up Memory
Ladder programs and PLC Setup are backed up to the built-in EEPROM backup memory by trans-
ferring them from the CX-Programmer or writing them using online editing.
Restoring Memory
Ladder programs and PLC Setup are automatically transferred from the built-in EEPROM backup
memory to the RAM memory when power is turned ON again or at startup.
Precautions for Safe Use
The BKUP indicator on the front of the CPU Unit turns ON when data is being written to the built-
in EEPROM backup memory. Never turn OFF the power supply to the CPU Unit when the BKUP
indicator is lit.
I/O memory is backed up to the built-in EEPROM backup memory only when a bit in the Auxiliary Area
is turned ON to back up specified words in the DM Area.
* The values will be cleared to all zeros at startup if the Clear retained memory area (HR/DM/CNT) Check Box is
selected in the PLC Settings.
3-2-2 Backing Up Ladder Programs and PLC Setup
3-2-3 I/O Memory Backup
Area
Backup to built-in
EEPROM backup
memory
Status at startup
N/NA-type CPU Unit with
no Battery mounted or
E-type CPU Unit
N/NA-type CPU Unit with
Battery mounted
CIO Area Not backed up. Cleared to all zeros.
Work Area (W)
Timer Area (T)
Holding Area (H) Unstable when the power
supply is OFF for longer
than the I/O memory
backup time.
*
The values immediately
before power interruption
are retained.
Counter Area (C)
Auxiliary Area (A) Initialized (For N/NA-type
CPU Units, status of bits
related to clock functions
is unstable when the
power supply is OFF for
longer than the I/O mem-
ory backup time.
*
)
Initialized (For N/NA-type
CPU Units, status of bits
related to clock functions
are retained at their sta-
tus immediately before
power interruption.)
DM Area
(D)
Number of words start-
ing from D0 set in the
Number of CH of DM for
backup Box in the Star-
tup Data Read Area in
the PLC Settings.
The specified number of
words starting from D0 is
backed up by turning ON
A751.15 (DM Backup
Save Start Bit).
The specified number of words starting from D0 is
restored from the built-in EEPROM backup memory if
the Restore D0- from backup memory Check Box is
selected in the Startup Data Read Area in the PLC Set-
tings.
Ranges not given
above.
Not backed up. Unstable when the power
supply is OFF for longer
than the I/O memory
backup time.
The values immediately
before power interruption
are retained.
To Next Page
Loading...
