1. A weighing system for weighing an article, the system including a spring scale for measuring the weight of the article as a function of the deflection of a load support for carrying the article, the scale comprising means for generating an optical cyclic pattern, the generating means including means moving the pattern as a function of the load support deflection, optoelectronic transducer means, the pattern being projected upon the transducer means, the transducer means generating a pair of cyclic waveforms as a function of the deflection of the load support, the system further including an interface and a processing unit, the interface being disposed in the system between the transducer means and the processing unit, the interface including digital wave shaping means, the digital wave shaping means receiving the cyclic waveforms and in response thereto providing a pair of shaped digital waveforms, sensing means, the sensing means receiving the shaped waveforms and sensing movement of the load support and to provide one series of pulses indicative of movement in one direction and another series of pulses indicative of movement in an opposite direction, counting means coupled to the sensing means to receive either one of said series of pulses, and in response thereto in one instance adding the pulses of one series and in another instance subtracting the pulses of the other series to provide counter information indicative of the measure of said load support movement, and register means, the register means receiving the counter information and storing and transferring the counter information to the processing unit, the processing unit receiving the counter information and in response thereto processing said counter information for determining article weight.