Method and control units monitor

A method of monitoring data and the data transmission between at least either first and second control unit, wherein at least two control units have a leading programs which programs are associated calculating function and a second control plane programs monitoring the proper operation of programs in the foreground programs, the first control unit being connected to at least one component used for data entry, in particular quantities of data commande.Les entered or calculated by the components is transmitted from the first to the second control unit in a protected manner by a single bond, and are protected, separately, the data and the transmission data in the first and the second plane of programs, to recognize the defect data and transmission data.