Device and method for identifying a malfunction in an extracorporeal blood circulation

A machine control method for identifying a malfunction in an extracorporeal blood circulation of an extracorporeal blood treatment machine, comprising:

• detecting at least one state parameter characterizing the extracorporeal blood circulation;
• determining a first state parameter evaluation criterion for identifying at least one malfunction in the extracorporeal blood circulation;
• using the first state parameter evaluation criterion, making a decision with respect to the presence of at least one malfunction in the extracorporeal blood circulation, generating a first error signal, and monitoring the detected state parameter;
• determining at least one further state parameter evaluation criterion;
• using the at least one further evaluation criterion, making a decision with respect to the presence of a malfunction in the extracorporeal blood circulation and generating a further error signal;
• and
• combining the first error signal and the at least one further error signal to result in a combined error signal, wherein at least one of an alarm or an emergency stop is triggered if the combined error signal exceeds a predetermined limit value in positive or negative direction or is within a predetermined value range.