SYMINFOSTRUCT

TwinCAT PLC symbol information.

TYPE SYMINFOSTRUCT :
STRUCT
    symEntryLen  : UDINT;
    idxGroup     : UDINT;
    idxOffset    : UDINT;
    byteSize     : UDINT;
    adsDataType  : ADSDATATYPEID;
    symDataType  : T_MaxString;
    symComment   : T_MaxString;
END_STRUCT
END_TYPE

symEntryLen: The actual length in bytes of the symbol entry in the symbol table. The symbols are stored in a symbol table. The length of the individual entries is variable, and depends on the length of the symbol name, the type identifier and the comment.

idxGroup: The index group of the symbolic variables;

idxOffset: The index offset of the symbolic variables;

byteSize: The amount of memory, in bytes, actually occupied by the value of the symbolic variables. A boolean PLC variable, for instance, occupies one byte, while a string with 20 characters in fact occupies 21 bytes (20 bytes for characters plus one byte for the zero marking the end of the string);

adsDataType: The ADS data type ID. (Type: ADSDATATYPEID) This type identifier is used in ADS access to symbolic variables. All PLC structures and arrays (self-defined data types) have the ADS data type ID: ADST_BIGTYPE and cannot be identified via this data type constant. In order to be able to identify the user-defined data types, use the symDataType variable, or read the base type of the individual variables in the structure.

symDataType: The data type identification of the symbolic variable as a string. For instance this might be the type name of a PLC data structure defined by the user (type: T_MaxString, max. 255 characters).

symComment: A comment on the symbolic variable that the user has added to the PLC variable definition line (type: T_MaxString, max. 255 characters).