| 摘要 |
The invention relates to a counting apparatus having excellent fail-safe characteristics, and to a rotation stopped detection apparatus which uses the counting apparatus. With a first aspect of the invention, timing of a high frequency signal (P2) is carried out by a counter (1) after completion of counting of pulse signals (P1) of a signal to be counted. When the frequency of the timing output for the high frequency signal (P2) is a predetermined value, a judgment signal indicating that the counter is normal is generated from a frequency discriminating circuit (30). With a second aspect of the invention, a counter (100) is preset using a preset signal. Then, after verifying by an output from a self hold circuit (102) that the counter (100) has been reset, a counting output is generated from a self hold circuit (104). With a third aspect of the invention, the counting apparatus is used as timer circuits (203, 300, 400), and the generation frequency of a rotation detection pulse signal (Ip) based on a sensor signal, is obtained to thereby detect a rotation stopped condition of a rotation body. <IMAGE> |
