is it possible to connect the function generator to the power supply? and if its possible what is the input source?

 

because of the voltage limitations (e.g. the DC offset of the function generator) the extension supply is being used at the application that produced the picture of the circuit layout . . . the simulator in question has a load of shortcomings and can't be used to predict the real world processes

 

No.
In the real world the function generator would be destroyed.