Patent ID: 7209862

Claim:
A self-diagnosing system for an encoder, comprising: an encoder circuit for outputting information detected by an encoder; a data preparing section provided in said encoder circuit, said data preparing section preparing data representing a state of an abnormal-state judgment factor in connection with at least one of the encoder and an electric motor combined with the encoder; a signal generating section provided in said encoder circuit, said signal generating section generating an abnormal-state signal when said data prepared in said data preparing section represents an abnormal state of said abnormal-state judgment factor; and a storage section provided in said encoder circuit, said storage section storing said data representing a state of said abnormal-state judgment factor when said signal generating section generates said abnormal-state signal; wherein said storage section stores said data prepared in said data preparing section at a desired timing not later than an instant said signal generating section generates said abnormal-state signal.