Mitsubishi Electric MELSEC FX3U Programming Manual page 787

FX /FX /FX Series Programmable Controllers
3G 3U 3UC
Programming Manual - Basic & Applied Instruction Edition
2. Allowable number of writes to the memory
Note the following cautions on access to extension file registers.
• 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.
Errors
An operation error is caused in the following cases; The error flag M8067 turns ON, and the error code is
stored in D8067.
• When any device number other than the head device number of a sector of extension file registers (ER) is
set to (error code: K6706)
S
• When a device number to be initialized exceeds "32767" (error code: K6706)
In this case, devices up to R32767 (ER32767) are initialized.
• When the protect switch of the memory cassette is set to ON (error code: K6770)
• When a memory cassette is not connected (error code: K6771)
Program example
In the program example shown below, the extension file registers ER0 to ER2047 in sector 0 are initialized.
X000
• Extension file registers (ER) [inside the memory cassette]
Device number
ER0
ER1
ER2
ER2047
FNC 07
WDT
FNC295
R0 K1
INITER
FNC 07
WDT
END
Current value
Before execution After execution
H1234 HFFFF
H5678 HFFFF
H90AB HFFFF
HCDEF HFFFF
33 Extension File Register Control – FNC290 to FNC299
33.6 FNC295 – INITER / Initialize ER
31
32
33
34
35
36
37
38
A
B
785