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FX3S/FX3G/FX3GC/FX3U/FX3UC Series
Programming Manual - Basic & Applied Instruction Edition
33 Extension File Register Control – FNC290 to FNC299
33.2 FNC291 – SAVER / Save to ER
2. Initialization of extension file registers
Execute the INITER (FNC295) or INITR (FNC292) instruction to target extension file registers (ER) before executing
the SAVER instruction. If the SAVER instruction is driven before the INITER (FNC295) or INITR (FNC292) instruction
is executed, an operation error (error code: K6770) may occur.
To avoid this an operation error, make a program executing the SAVER instruction as shown in the following
sequence:
• If the FX
3U/FX3UC PLC is Ver. 1.30 or later
[1] When storing sectors of 2,048 extension registers (R) to extension file
registers (ER)
1) Execute the INITER (FNC295) instruction to the target extension file registers (ER) specified as targets in
the SAVER instruction.
2) Execute the SAVER instruction.
[2] When storing an arbitrary number of extension registers (R) to extension file registers (ER)
Use the RWER instruction.
→ For RWER (FNC294) instruction, refer to Section 33.5.
• When the FX
3UC PLC is before Ver. 1.30
[1] When storing sectors of 2,048 extension registers (R) in one sector to
extension file registers (ER)
If the extension registers (R) have data to be stored in extension file registers (ER), use the procedure [2].
1) Execute the INITR (FNC292) instruction to extension registers (R) and extension file registers (ER)
specified as targets of the SAVER instruction.
2) Store data to extension registers (R) specified as targets.
3) Execute the SAVER instruction.
[2] When storing sector of 2,048 extension registers (R) in one sector to extension file registers (ER)
1) Temporarily withdraw the data of the extension registers (R) specified as targets of the SAVER instruction
to data registers or 2048 unused extension registers (R) by using the BMOV (FNC 15) instruction.
2) Execute the INITR (FNC292) instruction to extension registers (R) and extension file registers (ER)
specified as targets of the SAVER instruction.
3) Return the data of 2048 points temporarily withdrawn in step 1) to extension registers (R) specified as
targets by using the BMOV (FNC 15) instruction.
4) Execute the SAVER instruction.
3. 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. To prevent 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.