The IEC operator is used as a multiplexer.

‎OUT := MUX(K, IN0,...,INn)‎

That means: ‎OUT = IN_K‎

Permitted data types for ‎K‎: ‎BYTE‎, ‎WORD‎, ‎DWORD‎, ‎LWORD‎, ‎SINT‎, ‎USINT‎, ‎INT‎, ‎UINT‎, ‎DINT‎, ‎LINT‎, ‎ULINT‎ ‎UDINT‎

‎IN0‎, …, ‎INn‎ and ‎OUT‎: any identical data type

Make sure that variables of the identical type are used at all three positions, especially when using user-defined data types. The compiler checks for type identity and returns any compile errors. The assignment of function block instances to interface variables is specifically not supported.

‎MUX‎ selects the K-th value from a set of values. The first value is K=0. If ‎K‎ is greater than the number of other inputs (n), then CODESYS passes on the last value (‎INn‎).

NOTICE

For runtime optimization, CODESYS computes only the expression which precedes ‎IN_K‎. However, in simulation mode, CODESYS computes all branches.

Var1 := MUX(0,30,40,50,60,70,80);