Mitsubishi Electric MELSEC FX3U Programming Manual page 782

FX /FX /FX Series Programmable Controllers
3G 3U 3UC
Programming Manual - Basic & Applied Instruction Edition
3. Allowable number of writes to the memory
Note the following cautions on access to extension file registers.
• In FX /FX
3U 3UC
Data can be written to the memory cassette (flash memory) up to 10,000 times.
Every time the INITR (FNC292), RWER (FNC294) or INITER (FNC295) instruction is executed, it is
counted as a write to the memory. Make sure not to exceed the allowable number of writes.
When a continuous operation type instruction is used, data is written to the memory in every operation
cycle of the PLC. For preventing this, make sure to use a pulse operation type instruction.
Execution of the LOADR (FNC290), SAVER (FNC291) or LOGR (FNC293) instruction is not counted as a
write to the memory. However, it is necessary to initialize the writing target sector before executing the
SAVER (FNC291) or LOGR (FNC293) instruction.
Every time the INITR (FNC292)or INITER (FNC295) instruction is executed, it is counted as a write to the
memory. Make sure not to exceed the allowable number of writes.
• In FX PLCs
3G
Data can be written to the memory cassette (EEPROM) up to 10,000 times, and to the built-in memory
(EEPROM) up to 20,000 times.
Every time the RWER (FNC294) instruction is executed, it is counted as a write to the memory. Make sure
not to exceed the allowable number of writes.
When a continuous operation type instruction is used, data is written to the memory in every operation
cycle of the PLC. For preventing this, make sure to use a pulse operation type instruction.
Execution of the LOADR (FNC290)instruction is not counted as a write to the memory.
780
PLCs
33 Extension File Register Control – FNC290 to FNC299
33.5 FNC294 – RWER / Rewrite to ER