Abstract: An ignition device for internal combustion engines includes a monitoring device for a closing duration of a primary current circuit of at least one ignition coil, being set into motion simultaneously with an onset of closure of the primary current circuit and opening the primary current circuit again after a monitoring duration has elapsed, in the event that the circuit is still supposed to be closed at that time. The monitoring duration is adjusted as a function of the closing duration to be monitored.

Abstract: A process for generating a data structure of a computer model of a processed workpiece. The contours of the workpiece and the cross section of the tool, as well as the path movement of the tool, are analyzed in a grid such as is presented by a raster picture screen and associated image point memory of a microprocessor controlled graphic control unit of a numerically controlled machine tool. At each point of the coordinated grids the height of the workpiece is linked with the programmed processing depth of the tool and in this way the altered data structure of the workpiece is determined. The altered data structure can serve for the representation of the computer model thus determined on a picture screen. The linkage of the data from grid point to grid point is thus reduced to a number comparison for the Z coordinate, thereby maintaining both computer and apparatus capital expenses at a low level.