A compensation system for calibrating an amplifier having a compensation input including a sigma delta converter, a counter, a memory, adjust logic, a DAC, a pair of compensation capacitors, and a pair of current to voltage converters. The syringe carrier includes at least one rearward facing abutmer member to abut at least one forward facing surface on a syringe. The door provides and restricts access to the space in respective open and closed positions. The pair of brake discs rotate freely relative to the driving wheels. The distance across the bounded portion in the longitudinal direction of the board is greater than in the transverse direction.