Hi All, I'm a new AB programmer but I have experience in programming with Siemens. I want to use Add-on instruction in AB same as Function Block in Siemens, so that some inputs is not mandatory to write something and in this case it take their defined values. In AB, I found Add-on same as FB except that if you put it as required, so you should assign something to it and if not put it as required, you couldn't assign anything. Is there any way to have both together? Thanks