Format in what way? As in the datatype, or the number of decimal places, or something like that? If you want to do customization, you can convert the Express VI to a regular VI and you can then modify it to your heart's content. To do so:
- Start off with placing the Express VI on the block diagram, and add the inputs that you want.
- Then, right-click on the Express VI icon on the block diagram and select "Open Front Panel". You will get a dialog asking you if you want to convert the Express VI to a regular VI. Click on the "Convert" button.
- A new VI will open, and you can modify the controls as you need.
- Save the new VI in your project's directory structure.
You will notice that the icon on the block diagram will have changed to an ugly shade of yellow and not look like a regular VI icon. Just right-click on it and select "View As Icon".