Motorola Corporation

Landis & Gyr Metering, Inc.

Gordon R Burns

Kenneth R Burch

William A Szabela

An electronic demand register includes a microprocessor including a program clock for performing timekeeping functions for the register. A power supply connected across the AC voltage source provides power to the microprocessor through a voltage regulator. The program clock is maintained by the line frequency of the AC source. Electronic circuits are provided for calibrating the program clock to be compatible with either a 50 Hz or a 60 Hz line frequency. A detection signal corresponding to the line frequency is generated by a line frequency detector circuit in the power supply. A reference signal is generated by a quartz crystal clock. A frequency comparator circuit includes a microprocessor program that measures the time period between detection signal pulses. This time period is compared to the known period of a 50 Hz or a 60 Hz signal and respective counters are incremented accordingly. The microprocessor and program clock operating parameters are established for either 50 Hz of 60 Hz operation when one of the counters has reached a value of five, indicating that five zero crossings have been detected at the particular frequency. The electronic demand register also comprises a display including an array of LCD segments for continuous simultaneous display of the time and date. The display also includes an array of LCD segments, arranged in a pattern, that are sequentially illuminated corresponding to the rate of rotation of the shutter disk of the pulse initiator.

Program clock for an electronic demand register with automatic

First and second unused bits of a multi-bit mapped register are utilized to control a desired function. Each of the bits are capable of assuming first and second stable states. The control function is enabled when the first bit is in the first state and the second bit is in a second state. The function is disabled when the first bit is in the second state and the second bit is in the first state. The function remains unaltered when the first and second bits are each in the same state.

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Lafayette, IN, United States of America

Gordon R Burns