changing cable

[knowledglikeanant]

Hello,

 

I have several problems with my project. I have to make a crane. The problem is that when I drive constrain the arm of the crane, the cable does not change its angle nor its size. see pictures

 

 

An other problem is that I want to drive constrain the assambly with excel or an add in program just like you can do with a joystick. Does anyone know how to do that?

 

Thanks for reading my message