According to the IEC 61131-3 standard, functions can have additional outputs. You declare the additional outputs
in the function between the keywords VAR_OUTPUT and END_VAR. The function is called according to the following syntax:
<function> (<function output variable1> => <output variable 1>, <function output variable n> => <output variable n>)
Example
The fun function is defined with two input variables in1 and in2. The output variable of the fun function is written to the locally declared output variables loc1 and loc2.
fun(in1 := 1, in2 := 2, out1 => loc1, out2 => loc2);