1. Press the position pos key (press the relative coordinate key to enter the current position if necessary) to enter the relative coordinate page, that is, display the current position value interface with U and W coordinates.

2. Press the U key or W key to make the U key or W key flash on the page, and then press the up key or down key repeatedly.

3. Each time the up button is pressed, the LCD gradually becomes darker; each time the down button is pressed, the LCD gradually becomes brighter.