A fluid control and processing system comprising a cartridge and an instrument for operating the cartridge. The cartridge comprises a cylinder body comprising a cylinder and a fluid port. It further comprises dispensing ports to drive a fluid flow, each dispensing port being positioned to be connectable, when the instrument is operating the cartridge, with at least a fluid port by rotation of the cylinder body. The instrument comprises a piston driver for driving the piston. The system further comprises: reversible fastening means for fastening the piston when the piston driver is rotated with respect to the piston, so that the movement of the piston is controlled by the piston driver; and rotating means comprising a cylinder driver constitutive of the instrument for rotating the cylinder body around the axis A.