Testable, fault-tolerant power interface circuit for controlling plant process equipment

摘要

A power interface circuit periodically which receives test pulses to test the operation and connections thereof. Voltage and current sensors detect the result of the testing and may be used for zero-crossing detection when AC powered devices are controlled by the power interface circuit. Preferrably, asymmetrical pulses, such as those representing an ASCII character, are used as the test pulses. Three input signals are received by the power interface circuit which performs two out of the three voting on the input signals to generate a control signal for two power switches. The power switches may be connected in parallel or in series to provide additional fault tolerance.