UNIVERSAL CONTACT INPUT APPARATUS AND METHOD FOR OPERATING THE SAME

摘要

At a contact input circuit, a voltage at a switching device is sensed and the voltage is associated with a status of a switching device. The contact input circuit is operated according to the sensed voltage regardless of the value of the sensed voltage. The power usage of the contact input circuit is maintained to be within a predetermined range of power consumption values regardless of the value of the sensed voltage. Wetting voltages can be continuously monitored and the approaches described herein can monitor open contact, closed contact, and open field wire conditions.