Setting the range of the pitch bend joystick

[Wallirec]

Hello, thank you for the best midi library, I made several controllers that are ideal for me and that you can't buy in a store! I assembled a pitch bend controller on the JoyStick Shield board (I bought three from different manufacturers), but the joystick gives out the final values ​​already at half the stroke. Please tell me how to set the extreme positions of the values ​​for the pitch bend?