ISPSoft User Manual In addition to the principles for the general data types described above, there are principles for the symbols whose data type is ARRAY. Basic principles for the symbols whose data types are ARRAY 1. The array type of P_Var must be the same as the array type of FB_Var. 2. If the array type of P_Var is the same as the array type of FB_Var, the size of the array for P_Var can be larger than the size of the array for FB_VAR. Special principles for the symbols whose data types are ARRAY 1. When the array types are compared, the first special principle for the general data types applies. 2.
If either the data type of P_Var or the data type of FB_Var is ARRAY, the system will regard the other symbol whose data type is not AARAY as a symbol whose data type is ARRAY, and the size of the array for the symbol will be one element. 3. If the array type of P_Var or the array type of FB_Var is WORD,INT, REAL or any other types, users can compare bothdata lengths by means of summation. For example, a symbol whose array type is DWORD is compatible with a symbol whose array type is INT and contains the length of two elements and for a symbol whose array type WORD and has a length of four elements is compatible with a symbol whose array type is LINT.
However, a symbol whose array type is INT and has a length of four elements is not compatible with a symbol whose array type is LINT, because both data types do not contain the array type of WORD and do not fit the principle. The following examples are: Example 1: The data type of P_Var (in the caller) is INT, and the data type of FB_Var (in the function block) is INT. The basic principle for the general data types is satisfied. As a result, the data types are legal. block) is INT. Example 2: The data type of P_Var (in the caller) is WORD, and the data type of FB_Var (in the function The first special principle for the general data types is satisfied.
As a result, the data types are legal. Example 3: The data type of P_Var (in the caller) is LWORD, and the data type of FB_Var (in the function block) is DINT 。 The first special principle for the general data types is satisfied. As a result, the data types are legal. ㄨ Example 4: The data type of P_Var (in the caller) is WORD, and the data type of FB_Var (in the function block) is LINT. Although the data type of P_Var is WORD, the data length of P_Var is less than that of FB_Var. As a result, the data types are illegal. 7-10