Abstract: A method is provided for the control of valves for flow path control, in particular in a medical treatment machine, having a plurality of processes for the manufacture of flow paths by control of a group of valves, with each process claiming a group of valves suitable for its carrying out for itself so that other processes cannot change the switching state of these valves and with each process itself making a decision on the release of the valves claimed by it. In addition, a method is provided for monitoring the then current and/or scheduled state of a plurality of valves in the flow path control, determining the connections resulting from the switching state of the valves, and comparing the resulting connections with a predetermined number of non-permitted connections.

Abstract: A dialyzer having a hemo-dialyzer and/or a hemo-filter and an extra-corporal blood circulation with which a device for the adding of citrate to the blood is connected upstream and a device for the adding of a substitution solution containing ions to the blood is connected downstream of the hemo-dialyzer and/or of the hemo-filter. Ion concentration in the dialyzate downstream of the hemo-dialyzer and/or of the hemo-filter is detected with respect to the direction of flow of the dialyzate. The concentration of the ion, atom or molecule to be determined is reliably ascertained by preventing the complexing of the ion, atom or molecule, at least during the determination of the concentration, by the addition or withdrawal of a substance.