| 摘要 |
PURPOSE:To improve resolution per bit without any change in the number of bits by converting analog signals from a position detecting means and a differential amplifier means to digital signals, and adding the signals for the calculation of a position. CONSTITUTION:As a fork 1 is elevated, for example, a position detecting sensor 2 outputs analog signals to an A/D converter 3a (10 bits), and differential amplifier circuits 4 and 5. As a result, the circuits 4 and 5 differentiate and amplify the signals on the basis of the prescribed reference voltage and analog signals. Furthermore, the amplified signals are outputted to A/D converters 3b and 3c. Also, a processing circuit 13 receives the digital signals outputted respectively from the converters 3a, 3b and 3c, and performs a process to add the signals for output to a position computing circuit 14a. Then, the circuit 14a computes the position of the fork 1 on the basis of the added signals. In this way, the addition of the digital signals differentiated and amplified with the circuits 4 and 5 can keep resolution per bit at 1.88m, when the position of the fork 1 changes within the range of 0 to 3,000mm. |
