46
FX
3G
/FX
3U
/FX
3UC
Series Programmable Controllers
Programming Manual - Basic & Applied Instruction Edition
2 Overview (Sequence Program)
2.7 Types and Setting of Parameters
2.7.3
Memory capacity setting range
~
Built-in memory capacity
3
Can be set by changing parameter.
Cautions 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:
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
*1
, 8 blocks (4000 steps) are used.
4) In the positioning setting
*2
, 18 blocks (9000 steps) are used.
5) In the built-in CC-Link/LT setup
*3
, 1 block (500 steps) are used.
*1.
This item is supported only in FX
3U
/FX
3UC
PLCs, and can be set using GX Developer Ver. 8.24A or later.
*2.
This item can be set using GX Developer Ver. 8.24A or later in FX
3U
/FX
3UC
PLCs, and using GX Developer
Ver. 8.72A or later in FX
3G
PLCs.
*3.
This item is supported only in the FX
3UC
-32MT-LT-2, and can be set using GX Developer Ver. 8.68W or later.
Caution
• After changing the memory capacity setting, make sure to write both the programs and parameters to the PLC.
If only the parameters are written to the PLC, program errors (such as parameter error, circuit error and grammar
error) may occur in the PLC.
• FX
3G
PLCs operate in the extension mode when the program capacity (which is available for sequence programs,
and excludes the comment capacity, file register capacity, etc.) is 16,001 steps or more, and operate in the
standard mode when the program capacity is 16,000 steps or less. The instruction execution time is shorter in the
standard mode than in the extension mode.
Example:
Time required to execute the basic instruction "LD"
Standard mode: 0.21
μ
s
Extension mode: 0.42
μ
s
• The FX
3U
/FX
3UC
PLC can store symbolic information in the following capacity:
- The FX
3U
-FLROM-1M (memory cassette) has an area dedicated to the storage of symbolic information, and can
store up to 1300 kB.
- When storing the symbolic information in any memory cassette other than the FX
3U
-FLROM-1M or to the built-in
memory, make sure that amount of the symbolic information to be stored does not exceed the available memory
capacity.
It is recommended to use the FX
3U
-FLROM-1M when there is a large amount of symbolic information to be
stored.
Symbolic information capacity = Maximum capacity of memory cassette - Memory capacity set by parameters
It is possible to check the symbolic information capacity using the memory capacity calculation (offline) of GX Works2.
→
Refer to the GX Works2 Version 1 Operating Manual (Common) for details.
• 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.
Memory capacity setting
Comment
capacity setting
Unit: Block
File register
capacity setting
Unit: Block
Special unit
initial value
setting
*1
Unit: Block
Positioning
setting
*2
Unit: Block
Built-in CC-Link/
LT Setup
*3
Unit: Block
Number of
steps
FX
3U
FX
3UC
FX
3G
2000 steps
3
3
0 to 3
0 to 3
–
–
1
4000 steps
3
3
0 to 7
0 to 7
–
–
1
8000 steps
3
3
0 to 15
0 to 14
8
–
1
16000 steps
3
3
0 to 31
0 to 14
8
18
1
32000 steps
3
~
0 to 63
0 to 14
8
18
1
64000 steps
~
–
0 to 127
0 to 14
8
18
1
Memory capacity
setting range
Comment
capacity setting
≥
File register
capacity setting
Special unit initial
value setting
*1
Positioning
setting
*2
*3
+
+
+
Built-in CC-Link/LT
Setup
+
