how to bring of subvis to the front panel of main vi?

[Glnan]

I am working on a simulaton project where a PID control toolkit is used to controla process .How can I access the controls of this PID controller when I execute the main VI ?

[tst]

I'm not sure I understand. The PID VIs I know run within your code on a loop basis. In every iteration of the loop they run using the values you input and output the proper values. So, to input values, you simply wire controls into them. Regardless of this, to open the front panel of a VI, you need to get a reference to that VI (using open VI reference) and wire that reference into a property node (both can be found in the Application Control palette).
Select the Front Panel>>Open property, wire T into it and the FP will open. You can also set the VI to have its front panel open when called in File>>VI properties.