Mitsubishi Electric MELSEC-Q Structured Programming Manual page 278

FXCPU Structured Programming Manual
[Device & Common]
Caution on setting the memory capacity
• When one block is set in each capacity setting, the memory capacity is reduced by 500 steps.
Each setting should satisfy the following expression:
Memory capacity
>
setting range capacity setting
1) With regard to the comment capacity, up to 50 device comments can be set in one block.
2) With regard to the file register capacity, up to 500 (16-bit) file registers can be set in one block.
3) In the special unit initial value setting, 8 blocks (4000 steps) are used.
4) In the positioning setting, 18 blocks (9000 steps) are used.
5) In the built-in CC-Link/LT setup, 1 block (500 steps) are used.
Cautions
1) After changing the memory capacity setting, make sure to write both programs and parameters together
to the PLC.
If only parameters are written to the PLC, program errors (such as parameter error, circuit error and
syntax error) may occur in the PLC.
2) When the memory capacity of the FX
and the total of the comment capacity and the file register capacity is limited to 12000 steps (24 blocks).
The comment capacity is automatically set when the file register capacity is set.
3) FX /FX
3G 3GC
in the standard mode when the program capacity is 16000 steps or less.
The instruction execution time is longer in the extension mode than in the standard mode.
Example: LD (basic instruction) execution time
Standard mode: 0.21 μs
Extension mode: 0.42 μs
4) The PLC can store symbolic information in the following capacity:
Make sure that the capacity of symbolic information to be stored does not exceed the available capacity.
- In the case of built-in memory, 16K memory cassette (FX
(FX -FLROM-64 and FX
3U
Symbolic information capacity = Maximum capacity of memory - Capacity of memory set by
parameters
- In the case of FX
Fixed to 1300 kB
It is recommended to use the FX
be stored.
It is possible to check the symbolic information capacity using the memory capacity calculation (offline)
of GX Works2.
5) When symbolic information is stored, it is deleted if the memory capacity set by parameters is changed.
After changing the memory capacity, write the symbolic information again.
276
Comment
+
PLCs operate in the extension mode when the program capacity is 16001 steps or more, or
-FLROM-64L)
3U
-FLROM-1M
3U
-FLROM-1M when there is a large amount of symbolic information to
3U
Special unit initial
+
value setting
PLC is 16000 steps, the program capacity is fixed to 4000 steps,
3S
-FLROM-16) and 64K memory cassette
3U
→ For datails, refer to the GX Works2 manual.
6 Types and Setting of Parameters
6.3 Memory Capacity Setting Range
Positioning
Built-in CC-Link/LT
+ +
setting
Setup