Abstract: The present disclosure relates to a biological fluid processing system and method. The system comprises a fluid processing device comprising at least one fluid path, a pump for providing a pressure in the at least one fluid path, a valve arranged along said fluid path and a first actuator arranged to control the valve to assume a desired opening state of said fluid path. The biological fluid processing system comprises further a processing interface comprising a pump drive for driving the pump of the fluid processing device, and a processing control element comprising a pump control system arranged to control at least the pump drive and a valve control system arranged to control the first actuator. The system is modular. The fluid processing device is comprised in a fluid processing device module having a predetermined fluid processing device configuration. The processing interfaces have a predetermined processing interface configuration.