A check valve assembly for use in a plastic injection molding machine injection unit is disclosed. The function executing device may not execute the change process in a case where the state of the function executing device is determined as an error state. Thus, during the pumping cycle, a gas transfer from a bottom chamber to the case part above a piston and an oil transfer from the case part above the piston to the bottom chamber is established. A system according to the invention includes a first and a second cell, which have cell outgoing conductors that are connected and shaped in this way. The cell is mechanically refueled by expanding the soft pocket to allow easy removal from the cell of the spent anode and easy insertion into the cell of a fresh anode. The insertion position for the respective RPLM syntax element corresponds to a position in the ordered set of RPLM syntax elements of the respective RPLM syntax element.