Embodiments of the present invention are directed to a microcontroller which includes a Register Load Assist engine. The system has areas for displaying program schedule information. The apparatus includes an access plate at the bottom thereof allowing access to the interior of the enclosure of the apparatus through a ceiling. Two frame-mounted, double-sided slider crank mechanisms are vertically arranged in the pipetting unit. A cylinder head, which can be fastened to the cylinder block, can apply a clamping force to the annular flange to clamp or fix the cylinder to cylinder.