Device and method for safely recognizing switch positions of a rotary switch
AssigneeSiemens Aktiengesellschaft
InventorsGunter Schwesig, Guido Seeger
Life of this patent
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Abstract
A device and method is described for safely recognizing a switch position angle of a rotary switch. Two redundantly configured computer units are provided to determine discrete switch positions of the rotary switch by evaluating two actual analog switch position signal values corresponding to the switch position angle, with each computer unit separately checking the actual analog switch position signal values for plausibility. Faulty switch position angles are identified by comparing the switch position angles determined by the first and the second computer unit.
Claims11
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 90°, 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.
A method for safely recognizing a switch position angle of a rotary switch, comprising the steps of
- digitizing two actual analog switch position signal values having a predetermined amplitude characteristic which reflects the switch position angle,
- providing the two digitized actual switch position signal values separately to two redundantly configured computer units in the form of sinusoidal signals having each a constant amplitude and being phase-shifted with respect to each other by 90°,
- evaluating in the two redundantly configured computer units actual the two digitized switch position signal values, with each computer unit checking the actual digitized switch position signal values for plausibility,
- determining discrete switch positions of the rotary switch from the evaluated two actual digitized switch position signal values, and
- performing a plausibility check such that the switch position angle is 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.
Dependencies are inferred from the claim text.