SCALE READING AND COUNTING DEVICE

PURPOSE:To make it possible to divide a general purpose-digital scale into multiple parts and to read the scale at a high speed, by providing a circuit, which divides the pitch of the scale coarsely and counts the divided parts, a circuit, which divides the inside of the pitch finely and counts interpolated values, and a circuit, which detects the speed of displacement. CONSTITUTION:When a length X is measured, a starting point Ps is located at a position separated by M1 from a coarse divided point of a scale signal, which has passed at the last time. The value of M1 is read at the time of measurement by a phase modulation dividing method and memorized. Then, by the displacement along the scale, a scale signal in a sine waveform is detected. The number (n) of pulses, which are generated every time the coarse dividing point is passed is counted and stored. At a final point Pe of the measurement, the value M2 from the coarse dividing point, which is passed at the last time, is read by the phase modulation dividing method. Depending on whether the signal from a speed detecting circuit 5 is at a high speed or at a low speed, carry-out and carry-down pulse signals are made to be a B signal from a coarse system (b) or to be an A signal from a fine system (a). This is selected by an A.B signal-switching circuit 12. The measured counted value is displayed based on the counted values stored in a counted (n) pulse value memory circuit 9 and an M1.M2 memory circuit 7.