There is a gap between the screw axis and ball bearing or nut. Therefore, the nut does not move even after the screw axis begins to shift until the gap distance is traveled. This mechanical allowance along the direction of the slider movement is called “backlash”.
●BCD（Binary Coded Decimal）
One of measures to deal with decimal numbers in computers. A one-digit decimal number (0 to 9) is represented by a four-digit binary number.