Omron SYSMAC CX-Programmer 8.1, Operation Manual

Page: 54 / 154

Precautions When Creating SFC Programs Section 1-5
38
1-5-6 Memory Allocation
In CX-Programmer, the system allocates memory automatically to steps, transitions,
and actions. With the factory default setting, the “FB Non Retain” memory area (H512
and later) of the function block will be allocated.
This memory area may be insufficient, however, for larger SFC programs. In this case,
use the “SFC bit” and “SFC word” memory areas for SFC.
When using the “SFC bit” and “SFC word” memory areas for SFC, uncheck the Share
SFC with FB Memory checkbox.
Default Value Memory Area
First Address End Address Size
Allocable
Area
FB Non Retain H512 H1407 896 CIO, WR, HR, DM,
EM
FB Retain H1408 H1535 128 HR, DM, EM
FB Timer T3072 T4095 1024 TIM
FB Counter C3072 C4095 1024 CNT
SFC Bit N/A N/A N/A -
SFC Word N/A N/A N/A -
Note: DM or EM can be used for the "FB Non Retain" memory area. Uncheck the Share SFC
with FB Memory checkbox, since neither DM nor EM can be used as memory areas for
SFC.
Setting Procedure
1 Select Memory Allocation – Function Block/SFC Memory – Function
Block/SFC Memory Allocation from the PLC menu.
The Function Block/SFC Memory Allocation Dialog Box will be displayed.
2 Uncheck the Share SFC with FB Memory checkbox.
3 Select SFC Bit or SFC Word .
4 Click the Edit Button in the Function Block/SFC Memory Allocation Dialog Box.
The Edit Function Block/SFC Memory Range Dialog Box will be displayed.
5 Select Memory Area and input First Address and Size .
6 Click the OK Button in the Edit Function Block/SFC Memory Range Dialog Box.
7 Click the OK Button in the Function Block/SFC Memory Allocation Dialog Box.
Note: Set the memory areas for both "SFC bit” and “SFC word”.