US 6,148,055 A · Counter and a revolution stop detection apparatus using the counter

Abstract

A counting apparatus having excellent fail-safe characteristics can be used in a rotation-stopped detection apparatus. As a first feature, timing of a high-frequency signal P.sub.2 is carried out by a counter 1 after completion of a counting of pulse signals P.sub.1. When the frequency of the timing output for the high-frequency signal is a predetermined value, a judgment signal, indicating that the counting is normal, is generated by a frequency discriminating circuit 30. As a second feature, 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. As a third feature, the counting apparatus is used as timer circuits 203, 300, 400, and the generation frequency of a rotation detection pulse signal I.sub.P based on a sensor signal, is obtained to thereby detect a rotation-stopped condition of a rotating body.

Claims10

Dependent claims

A counting apparatus comprising:

pulse counting means for counting the number pulses of a pulse signal being counted that is input thereto, and for generating an output when said number pulses of the pulse signal being counted reaches a predetermined value;
signal switching means for switching between said pulse signal being counted and a high frequency pulse signal of a higher frequency than said pulse signal being counted;
control means for controlling said signal switching means so that the pulse signal input to said pulse counting means is switched to said high frequency pulse signal when said output generated from said pulse counting means is input to said control means;
and
frequency discriminating means which is input with a dividing signal generated from said pulse counting means each time the number of said high frequency pulse signal input to said pulse counting means reaches said predetermined value, and which generates an output indicating that a counting operation of said pulse counting means is acceptable only when said dividing signal is a predetermined frequency.

2 more elements

A counting apparatus comprising:

pulse counting means made up of a plurality of frequency dividing circuits connected in cascade, for counting the number of pulses of a pulse signal being counted that is input thereto, and for generating an output when said number pulses of the pulse signal being counted reaches a predetermined value;
reset verification means for verifying, after input of a preset signal, that said output from said pulse counting means has become a low level and has been reset, and for then generating a reset verification signal;
output generating means for transmitting said output generated from said pulse courting means as an effective counting result output, under the proviso that said reset verification signal has been generated front said reset verification means;
and
a frequency discriminating circuit which generates an output signal, indicating that a counting operation of said pulse counting means is acceptable only when said output from said pulse counting means is a predetermined frequency.

2 more elements

Dependencies are inferred from the claim text.

Counter and a revolution stop detection apparatus using the counter

Life of this patent

Counter and a revolution stop detection apparatus using the counter

Life of this patent

Abstract

Claims10