Using a single microprocessor to control several relays

In modern power systems, from generators to the final load points, there are several electrical equipment and machines of various ratings. Each of them must have an effective protective system. This book describes the implementation of several relays using single microprocessor, the 8085. Here abnormal conditions are sensed by suitable sensors, and it is converted into suitable voltage level and fed into the microprocessor through an analog-to-digital converter. After checking the severity of the condition, using the multitasking concept, the microprocessor energizes the driver circuit to trip the suitable breakers. Here each relay is implemented by a combination of a lookup table and a counter. A two-relay microprocessor system is described here.