Mitsubishi MELSEC-Q QD77MS, User Manual

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Chapter 14 Common Functions
[3] Precautions during control
(1) Data can only be written to the flash ROM when the positioning control is not
carried out (when the PLC READY signal [Y0] is OFF).
A warning "In PLC READY (warning code: 111)" will occur if executed when
the PLC READY signal [Y0] is ON.
(2) Writing to the flash ROM can be executed up to 100,000 times.
If writing to the flash ROM exceeds 100,000 times, the writing may become
impossible, and a "flash ROM writing error (error code: 801)" will occur.
(3) After one power ON/PLC CPU reset operation, writing to the flash ROM
using a sequence program is limited to up to 25 times.
If the 26th writing is executed, a "flash ROM write number error (error code:
805)" will occur. If this error occurs, carry out the error reset or power
OFF ON/PLC CPU reset operation again.
Refer to "
Md.19
Number of write accesses to flash ROM
" of Section 5.1.9
"Types and roles of monitor data" for details.
Important
Do not turn the power ON/OFF or reset the PLC CPU during executing the flash
ROM writing. If the power is turned OFF or the PLC CPU module is reset to forcibly
end the process, the data backed up in the flash ROM/internal memory
(nonvolatile) will be lost.
[4] Execution data backup method
(1) Execution data backup (writing to the flash ROM/internal memory
(nonvolatile)) is carried out using the dedicated instruction "ZP.PFWRT".
(Refer to Chapter 15 "Dedicated Instructions" for details.)
(2) Refer to Section 7.2 "Data transmission process" for the data transmission
processing at the backup of the execution data.
(3) Execution data backup can also be carried out by the writing of the data
shown in the table below to the QD77MS buffer memory using the TO
command/intelligent function device.
The writing to the flash ROM/internal memory (nonvolatile) is executed at the
time point the data is written to the QD77MS buffer memory.
Buffer memory address
Setting item
Setting
value
Setting details
QD77MS2
QD77MS4
QD77MS16
Cd.1
Flash ROM write
request
1 Set "1" (flash ROM write request). 1900 5900
: Refer to Section 5.7 "List of control data" for details on the setting details.
When the writing to the flash ROM/internal memory (nonvolatile) is complete, "0"
will be set in "
Cd.1 Flash ROM write request" by the QD77MS automatically.