Omron CX-PROGRAMMER V9 Operation Manual page 147

PART 1: CX-Programmer
CHAPTER 4 – Reference
Note:
In the symbol table, specify an address in one of the above areas as the first address of the data
structure.
• Symbol Tables in Which Structure Symbols Can Be Registered
Structure symbols can be registered in the following symbol tables.
Note:
• Size of Structure Symbols
The maximum size of one structure symbol is as follows:
• Maximum Number of Structure Symbols
The number of structure symbols that is created for one PLC must satisfy the following formula:
Number of structure symbols + Number of members in those structure symbols ≤ 4,000
Example: A data structure with three members must be counted as 4 elements in determining if the
maximum number of data structures has been exceeded.
• Nesting Levels for Data Structures within Data Structures
A data structure can be used as the member of another data structure.
Data structures can be nested to up to eight levels.
• Subscripts of Data Structure Arrays
Either constants or symbols*1 can be used as subscripts of data structure arrays.
Addresses and formulas cannot be used.
*1: Symbols can be used only for the first data structure array.
• Subscripts of Array Data Structures
The subscripts must be constants.
Symbols, addresses, and formulas cannot be used.
Precautions for Data Structure Symbols
• Character Restrictions for Structure Symbol Names, Structure Data Type Names, and
Member Names
CX-Programmer _Page 64
•
CIO
•
WR
•
HR
•
DM
•
EM
Automatic address allocation is not possible for structure symbols.
•
Global symbol table
•
Local symbol tables for ladder programs
•
Internal variables and input-output variables in symbol (variable) tables for function
blocks written in ladder diagrams
Structure symbols cannot be registered for the following items.
•
Local symbol tables for ST programs
•
Local symbol tables for SFC programs
•
Input variables, output variables, and external variables in symbol (variable) tables for
function blocks written in ladder diagrams
•
Symbol tables for function blocks written in the ST language
•
Internal variables: 32,000 words
•
Input-output variables: 2,048 words
•
Character Strings That Would Be Confused with Area Specifications
A, AC, AR, C, CF, CNT, D, DIFF, DM, DR, E, EM, E0_, E1_, E2_, E3_, E4_, E5_,
E6_, E7_, E8_, E9_, EA_, EB_, EC_, ED_, EE_, EF_, E10_, E11_, E12_, E13_, E14_,
OMRON