Mitsubishi Electric D75D4, User Manual

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Appendix - 114
MELSEC-Q
APPENDICES
Appendix 10.9 Execution data backup function
When the QD75 buffer memory data is rewritten from the CPU module, "the data
backed up in the QD75 flash ROM" may differ from "the data (buffer memory data) for
which control is being executed". In cases like these, the data being executed will be
lost when the programmable controller power is turned OFF.
(Refer to CHAPTER 7.)
In cases like these, the "execution data backup function" backs up the data being
executed by writing it to the flash ROM. The data that was backed up is then written to
the buffer memory when the power is turned ON next.
The details shown below explain about the "execution data backup function".
[1] Execution data backup means
[2] Control details
[3] Control Precautions
[4] Execution data backup method
[1] Execution data backup (written to flash ROM) means
 The backup is executed with a program.

The backup is executed by GX Works2.
Refer to GX Works2 Version1 Operating Manual (Common) for execution data
backup method by GX Works2.
[2] Control details
The following shows the data that can be written to the flash ROM using the
"execution data backup function".
Buffer memory Flash ROM
Parameters ( Pr.1 to Pr.57 ,
Pr.70 , Pr.150 )
Parameters ( Pr.1 to Pr.57 ,
Pr.70 , Pr.150 )
Positioning data (No. 1 to No. 600)
Positioning data (No. 1 to No. 600)
Block start data (No. 7000 to 7004) Block start data (No. 7000 to 7004)
[3] Control Precautions
(1) Parameter initialization is only executed when the positioning control is not
carried out (when the PLC READY signal (Y0) is OFF). The warning "In PLC
READY" (warning code: 111) will occur if executed when the PLC READY
[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 an error "Flash ROM write error" (error code: 801) will occur.
(3) After one power ON/CPU module reset operation, writing to the flash ROM
using a program is limited to up to 25 times.
If the 26th writing is executed, an error "Flash ROM write number error" (error
code: 801) will occur. If this error occurs, carry out the power OFF ON/CPU
module reset operation again.
Refer to Md.19 of Section 5.1.7 "Types and roles of monitor data" for
details.
Important
Do not turn the power ON/OFF, reset the CPU module, during writing to the flash ROM. If the
power is turned OFF or the CPU module is reset to forcibly end the process, the data backed
up in the flash ROM will be lost.