| 摘要 |
<P>PROBLEM TO BE SOLVED: To solve a problem wherein processing made to memorize to a non-volatile memory for every battery exchange by live wire work and power down is required for retaining position data even if a battery for retaining the position data of an absolute value encoder is exhausted. <P>SOLUTION: The revolution number is usually detected by a detection circuit by power source-backing up the revolution number by the battery and a position is obtained by combining the revolution number data with an absolute position in one rotation. When the battery voltage is reduced at power down by a battery voltage detection means, the revolution number data are temporarily backed up at the non-volatile memory in the device and the position data are prepared by combining with the data in one rotation at next feeding of power source. When the battery is not exchanged, it is made abnormal in the case where the position data by combining with the data in one rotation at the next feeding of the power source and the position backed up by the encoder are compared and they are not largely consistent with each other. <P>COPYRIGHT: (C)2004,JPO |
