The needle movement is driven by a stepper motor connected to the spindle assembly by a toothed belt. The circular motion of the motor is converted to linear motion by the drive nut on the spindle assembly. The upper and lower needle positions are detected by reflection sensors on the needle station board, while the needle-in-vial position is determined by counting the motor steps from the upper needle-sensor position.
base-id: 3714634507
id: 3714634507