Understanding arguments
Where return types are a function’s output, arguments are a function’s input(s). Arguments are optional, as we saw with the Addition function, where no inputs were required. However, for many functions, especially for functions that do math like our Addition function, arguments are usually necessary to provide reusability to a function. For example, our Addition function only added two hardcoded values. For the most part, this function is useless unless we want to add 4 and 3 every time the function is called. As such, a better approach would be to modify our function to take values as inputs.
The first step in creating functions with arguments is declaring variables in the VAR_INPUT section of the file that was automatically generated by the POU wizard. For our modified Addition function, we are going to have the function take two inputs, a and b. As such, we’re going to modify that section of code to match the following. These are the...