Mitsubishi Electric MELSEC-Q Structured Programming Manual page 112

FXCPU Structured Programming Manual
[Device & Common]
2) Initialization using GX Works2
Select [Online] → [Clear PLC memory ...] in GX Works2, and clear [Data device].
Note that this operation initializes the contents of timers, counters, data registers, file registers and
extension registers.
3. Allowable number of times of writing data to the program memory
Pay attention to the following points when accessing extension file registers
• In the case of FX
The allowable number of times of writing is 10,000 or less in a memory cassette (flash memory).
Every time the INITR, RWER or INITER instruction is executed, each execution is counted as one time of
writing. Make sure that the allowable number of times of writing is not exceeded.
When a continuous execution type instruction is used, data is written to the memory in each operation
cycle of the PLC. For preventing this, make sure to use a pulse execution type instruction.
Even if the LOADR, SAVER or LOGR instruction is executed, each execution is not counted as one time of
writing.
However, it is necessary to initialize sectors to be written in advance before executing the SAVER or
LOGR instruction.
When initializing registers using the INITR or INITER instruction, note that each execution of the INITR or
INITER instruction is counted as one time of writing. Make sure that the allowable number of times of
writing is not exceeded.
• In the case of FX
The allowable number of times of writing is 10,000 or less in a memory cassette (EEPROM), and 20,000 or
less in the built-in memory (EEPROM).
Every time the RWER instruction is executed, each execution is counted as one time of writing. Make sure
that the allowable number of times of writing is not exceeded.
When a continuous execution type instruction is used, data is written to the memory in each operation
cycle of the PLC. For preventing this, make sure to use a pulse execution type instruction.
Even if the LOADR instruction is executed, each execution is not counted as one time of writing.
110
/FX PLCs
3U 3UC
/FX PLCs
3G 3GC
2.9 Extension Register [R] and Extension File Register [ER]
2 Devices in Detail