Detailed Description
2.7 Structure and functions of the basic program
PLC Basic Program Solution Line (P3 sl)
Function Manual, 08/2005 Edition, 6FC5397-0BP10-0BA0
2-53
The structure of the machine data used is specified in a UDT:
TYPE UDT 20
STRUCT
UDInt : ARRAY [0 .. 3 ] OF INT ;
UDHex0 : ARRAY [0 .. 15 ] OF BOOL ;
UDReal : ARRAY [0 .. 0 ] OF REAL ; //Description as field, for
// later expansions
END_STRUCT;
END_TYPE
Note
ARRAY OF BOOL are always sent to even-numbered addresses. For this reason, an array
range of 0 to 15 must generally be selected in the UDT definition or all Boolean variables
specified individually.
Although only a REAL value is used initially in the example, a field (with one element) has
been created for the variable. This ensures that extensions can be made easily in the future
without the symbolic address being modified.
An entry is made in the symbol table to allow data access in symbolic form:
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