ok, there is some confusion here.
first of all the code is doing exactly what you tell it to, though it is not what you would want.¨
my first question would be, why do you want to program objects when you can use the prebuilt objects that do exactly the same stuff? and if they don't do exactly what you want, then look at the code of those objects and take it from there.
to your example:
you are in fact outputting the value of the param_V added to the value of inlet_C to the outlets, so the incoming signal is not present in the output. you don't set the position of the dial with the inlet, they are separate controls. (you can of course add them to each other or subtract or whatever) look at the math/gain object on how a simple gain can be implemented. again, i am not sure, why you want to code your own object for such a basic task?