Patent ID: 6292524
Filing Date: 2001-09-18
Classification: G01D,G01P,G01R

Abstract:
A rotation stopped detection apparatus comprising:a counting apparatus comprising:pulse counting means for counting pulses of a pulse signal, and for generating an output when the number of pulses reaches a predetermined value;signal switching means for switching an input signal to said pulse counting means between said pulse signal and a high frequency pulse signal of a higher frequency than said pulse signal;control means for controlling said signal switching means so that a pulse signal to be input to said pulse counting means is switched to said high frequency pulse signal when said output from said pulse counting means is input to said control means;frequency discriminating means for receiving a dividing signal generated from said pulse counting means each time the number of pulses of said high frequency pulse signal to be input to said pulse counting means reaches said predetermined value, and for generating an acceptable judgment output indicating that the counting operation of said pulse counting means is acceptable only when said dividing signal is a predetermined frequency; anda rotation sensor for generating a rotation detection signal with a pulse interval which changes corresponding to the rotation speed of a rotating body;whereinthe pulse generation frequency of said rotation detection signal of said rotation sensor is measured by said counting apparatus, andan output indicating a rotation stopped condition is generated from said counting apparatus when said pulse generation frequency is equal to or less than a predetermined pulse generation frequency, and the counting operation of said pulse counting means is acceptable.