Dear Mr. Henkel,
I need a help to implement Fractional Order PID Controller using control builder F. I already make big effort and reading lot of papers to do that, what I could do till now that I make discretization for the controleer equation and used the user function block to implement this transfer function. But in this case I can't change controller parameters, so I need another method. if you can help me it will be very appreciated.
I'm not clear about your question so I will answer in a broad sense how to create parameters for User Function Blocks.
In order to create parameters for a user function block [UFB] you need to declare them in the UFB-interface specification. If you double click on the FB-Class object in the P-Tree the interface specification opens for editing.
In order to create a configurable parameter you need to create an interface element with the storage type of PARA_DPS or PARA_EXP. You find the Storage types explained in the section 10 User Function Blocks of the Engineering Manual IEC 61131-3 Programming manual. The PARA_DPS values can be referenced inside the UFB and thus influence the calculation.
The UFB comes with a default configuration dialog which only allows specification of the FB name, short- and long description. A dialog editor is available that allows customization of the configuration dialog, adding any of the declared interface parameters. With the so modified configuration dialog, UFB instances can be provided with configurable parameter values.
The dialog editor is available from the Interface Specification (FB-Class) via menu Edit/Dialog Editor. It is described in the same manual and section as mentioned above.
Let me know any specific questions you have to the process of creating parameters for User Function Blocks.