| 摘要 |
PURPOSE:To detect a fault of a rotary encoder and abnormality of a signal line such as wire breaking immediately by regarding leading edges of two 90 deg. out-of- phase rectangular output signals as a trigger and generating a one-shot pulse in each phase, and varying the output of AND between the both on binary basis according to an operation state. CONSTITUTION:An incremental type rotary encoder generates two out-of-phase rectangular waves proportional to the rotating speed of a motor shaft. Those are called phase phases A and B and 90 deg. out of phase with each other. Leading edges of the waveforms in the phases A and B are regarded as a trigger to generate one-shot pulses having some width. The width of the one-shot pulses is determined depending upon the resolution of the encoder and a controllable minimum rotating speed. The one-shot pulses generated with leading edges of the respective phases are ANDed to generate ''1'' all the time when the encoder is in normal operation and there is no break of a signal due to wire breaking. For the purpose, the AND result is checked to detect a fault of the encoder and the breaking of the signal line. |
