Semantic Error (SEM1064): The function '...' expects at least ... input parameter(s).
In a code worksheet, too less parameters are specified for a function.
Error example in ST: MyVar := ADD( Value_a );
The IEC 61131 standard defines some basic functions where inputs can be duplicated, i.e., inputs of the same data type can be added. Expandable functions are, for example, AND, OR and ADD.
After expanding such a function in FBD/LD, the minimum required parameters must be connected (2 in case of AND, OR, ADD). Duplicated inputs may remain free.