You can enter anything you want into a front panel. The program would have to wait for an input from an operator. Since it seems you're struggling a lot with LabVIEW and the hardware, I would recomend you keep it simple and use the Express VI called Prompt User for Input. Define an Input as RPM and have the Input Data Type as Numeric. Put this in your program were you need it. When the operator enters a value into the dialog box and clicks the OK button, it will return the entered value. The only interference is that whatever code you have running in the same loop as the Prompt User will be paused while it is waiting for input.
