Patent ID: 6831820
Filing Date: 2004-12-14
Classification: G05B,H01H

Abstract:
A device for safely recognizing a switch position angle of a rotary switch, comprising:two redundantly configured computer units that determine discrete switch positions of the rotary switch by evaluating two digitized actual switch position signal values having a predetermined amplitude derived by A/D conversion from corresponding analog actual switch position signal values which reflect the switch position angle, with each computer unit separately checking the digitized actual switch position signal values for plausibility, wherein if the two digitized actual switch position signal values are provided to the first computer unit and the second computer unit in the form of sinusoidal signals having each a constant amplitudes and being phase-shifted with respect to each other by 90Â°, then the plausibility check is performed such that the signals are deemed to be plausible if the sum of the respective squares of the digitized actual switch position signal values supplied to the first computer unit or the sum of the respective squares of the digitized actual switch position signal values supplied to the second computer unit is located in a predefined range.