An optical watthour meter digitizer

An optical watthour meter digitizer was developed which meets these criteria. Based on the induction-type watthour meter, the digitizer provides an output pulse for a fixed amount of energy use. The digitizer senses the motion of the rotor disc of the meter by optically detecting passage of a nonreflective area painted on the underside of the disc. The passage of such area initiates a logic compatible output pulse that can be used to measure power or energy usage in a variety of ways. The accuracy of the measurement is determined by the watthour meter. The resolution of the measurement is determined by the K/sub h/constant (in watthours per revolution) of the meter and the number of equally spaced targets painted on the disc. The resolution of this device can be as small as a fraction of a watthour; the resolution of the manually read register on a watthour meter is typically a fraction of a kilowatthour. Several digitizers were fabricated, bench tested, and installed in the field for long-term performance testing. All are performing satisfactorily.