Patent ID: 6700382
Filing Date: 2004-03-02
Classification: H01H

Abstract:
A method for detecting a switched state of a switch, which comprises the steps of:electrically connecting the switch to a voltage source and, when the switch is in a closed switch position, a high electrical interrogation current flows which is higher than or equal to a first current threshold value; providing the high electrical interrogation current for reducing undesired layers that form on contacts of the switch; detecting the switched state of the switch by evaluating at least one of a voltage and a current at the switch; electrically connecting a low interrogation current which is lower than or equal to a second current threshold value to the switch after the closed switch position is detected, the low interrogation current being supplied for a pre-selected time period which starts at a time at which the closed switch position of the switch is detected, the first current threshold value being higher than the second current threshold value; and increasing the low interrogation current which flows when the switch is closed to a value which is equal to or higher than the first current threshold value only after the time period has expired, the time period being dependent on at least one of operating conditions and ambient conditions of the switch.