Good morning to all,
I'm new and I'm starting to study the FBD language in codesys, I have a big doubt:
I understand that the RETURN command in FBD stops the execution of a POU.
If I create a POU-function that returns a value, such as a function that takes two INT inputs and returns their sum, how can I return a result?
For example In the example I attach, I would like to return the value of ret_sum.
I think that:
true --- RETURN
Is not correct.
Thanks to who will respond.

Originally created by: scott_cunningham

RETURN is a keyword for exiting a POU early, not for returning values like you find in other languages. In your example, the lines of code in your POU will be executed, ret_sum will be filled and you can access this value in your other POU that called the FB instance. VAR_OUTPUTs automatically work - just put a value into the variable.

PLCopen Programming guidelines recommends to not use the RETURN command. You can read more about it in the guidelines.

scott_cunningham hat geschrieben:
RETURN is a keyword for exiting a POU early, not for returning values like you find in other languages. In your example, the lines of code in your POU will be executed, ret_sum will be filled and you can access this value in your other POU that called the FB instance. VAR_OUTPUTs automatically work - just put a value into the variable.
PLCopen Programming guidelines recommends to not use the RETURN command. You can read more about it in the guidelines.

Thanks a lot for your answer scott_cunningham, I downloaded PLCopen Programming guidelines and I start to study.
I understand the use of return in a Program or in a Function Block, but it's still not clear for me how to return a value in a Function (that returns a value e.g. INT) in FBD language.
In my first example I did an error adding the Var_Output ret_sum, now my FBD box that represent my function have 2 output ,the returned value of the function itself and the output variable ret_sum.
What I try to do is a pure function that returns a INT value and I want, for example, call this function in a Program.
I attach the new example but something is surely wrong,in fact when I go in simulation mode my function return alway 0 (and not 3+2=5) when I call it from my Program PLC_Prg.
I'm almoust sure that this happens because I don't know how set the returned value in a Function in FBD language.
I try to find this information in Codesys help without success, sorry.

Use

MyFunc:=ret_value

Originally created by: scott_cunningham

Thanks Josep - I forgot to mention using the function name for the return...

@cassiel Here is what your function should look like in FBD:

Thanks a lot Josep and scott_cunningham for your hints! now I undertsand how to do a function that returns a value in FBD