In a hemodiafiltration apparatus, a control and command unit halts a replacement fluid supply pump and contemporaneously modifies the control mode of a blood pump passing from a control based on the pump velocity to a control based on the blood pressure measured by a sensor arranged downstream of a hemodiafilter. During a precharge period, a data driver applies a precharge voltage to a capacitor via a data line. The device that alters an oscillatory electric field includes a device that generates an oscillatory electric field that is phase-synchronized with an oscillatory electric field imposed on a conductive medium surrounding the implantable device. The front shell includes a frame portion enclosing the mating section and a retaining portion extending rearwardly from the frame portion and assembled to the base section. A second distortion compensating feature that provides amplification is found in the use of non-parallel legs used to connect the linkage loop to the housing. The robot moves to the location given by the person in response to the prompt.