| 摘要 |
PURPOSE:To detect accurately the magnitude and polarity of a rotating speed by deciding on the polarity of the speed detected value of the rotating machine quantitatively. CONSTITUTION:A generating circuit 2 counts a reference clock F and outputs a counter reset signal E and a data latch signal G at intervals of measured time T. A counter 4 counts a pulse train (A) and is reset with the signal E, and a latch 6 latches its counted value C right before the counter is reset in response to the signal G. A phase decision circuit 7 decides whether the rotation is forward or backward from the phase relation between two-phase pulse trains (A) and (B) and outputs a signal S at the time of backward rotation. A counter 3 counts the clock F only during the output of the signal S and is reset with the signal E. A latch 5 latches the counted value tau right before its resetting in response to the signal G. A CPU1 reads data out of the latches 5 and 6 at intervals of time T and calculates the speed according to specific algorithm. |
