MITSUBISHI ELECTRIC Mitsubishi Programmable Logic Controller QD75D - Manual (Page 600)

14 - 18
MELSEC-Q
14 DEDICATED INSTRUCTIONS
[Precautions]
(1) Do not turn ON the power and reset the PLC CPU while parameters, positioning
data and block start data are written to the flash ROM using the PFWRT
instruction.
A parameter error will occur or normal positioning start will become impossible
because the parameters, positioning data and block start data are not written
normally to the flash ROM.
If this occurs, restart the operation by the method shown below.
• For GX Configurator-QP, write the parameters, positioning data and block start
data again to the flash ROM.
• For a sequence program, write the parameters, positioning data and block start
data to the QD75 after initializing the parameters (PINIT instruction execution
and others).
Then execute the PFWRT instruction again.
(2) A writing to the flash ROM is up to 100,000 times.
If writing to the flash ROM exceeds 100,000 times, the writing to the flash ROM will
become impossible.
(3) After the power ON and PLC CPU reset operation, writing to the flash ROM using
a sequence program is limited to up to 25 times. (Not limited to up to 25 times
when writing to the flash ROM is carried out by peripheral device.)
If the 26th or more writing is requested after the power ON/PLC CPU reset
operation, a flash ROM write number error (error code: 805) will occur, and the
writing will be disabled. If a flash ROM write error occurs by one writing to the
flash ROM, check and correct the flash ROM writing program. Then reset the
error or turn ON the power and reset the PLC CPU again.
(4) The PFWRT instruction can only be executed when the QD75 READY signal (X0)
is turned OFF.
When the QD75 READY signal is turned ON, the PFWRT instruction cannot be
executed.
Before executing the PFWRT instruction, turn OFF the PLC READY signal (Y0)
and then turn OFF the QD75 READY signal.
(5) When the remote I/O station (Q Corresponding MELSECNET/H network remote
I/O module) is used, the dedicated instruction (PFWRT) is unusable.
: For details of the remote I/O station, refer to Q Corresponding MELSECNET/H
Network System Reference Manual (Remote I/O Network).