| 摘要 |
PURPOSE: To eliminate the error produced in the present position data without returning a mobile part to its original point. CONSTITUTION: The number of pulses of a sensor signal consisting of the A- phase and B-phase signals outputted from a rotary encoder 2 undergo the addition/subtraction with a present position counter 4. This count value is defined as the present position data. When the moving direction of a mobile part 21 is fixed, the expressions (Pz-Iz)÷P... (a) and P×N+Iz... (b) are successively calculated based on a fact that a Z-phase signal is outputted every time the sensor signal is outputted in a fixed frequency. Then, the count value of the counter 4 is corrected into the calculation result value of the expression (b). In both expressions (a) and (b), Pz shows the count value of the counter 4 at a relevant time point together with P showing a fixed frequency, Iz showing the initial value of the counter 4, and N showing the quotient of the calculation result of the expression (a) respectively.
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