| 摘要 |
PURPOSE:To obtain interpolation data in accordance with a correlation table previously written in an ROM, by A/D-converting the 2-phase output of an encoder into digital quantities and leading these signals as the address input of the ROM. CONSTITUTION:When a motor 1 makes one turn, sine wave signals of several hundreds-several thousands cycles are outputted from a rotary encoder 2 for one turn of motor shaft as two phase signals, A-phase signal and B-phase signal, between which a phase difference of 90 deg. exists. Extents of the A-phase and B-phase signals containing -V-+V are converted into digital quantities by means of A/D converter circuits 3 and 4 and the digital quantities are respectively designated as A<1> and B<1>. If a 4-bit A/D converter is used as the A/D converters, it can cope with 16-stage of digital quantities. Then data of the 4-bit digital signals A<1> and B<1> are combined to 8-bit data and led to the address selective input of an ROM 5. A correlation table is stored in the ROM 5 in advance and outputs 4-bit interpolation data. |
