Controller for a stepping motor
AssigneeFujitsu Takamisawa Component Limited
InventorShukou Yamaji
Life of this patent
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Abstract
The present invention provides a controller with a function of detecting status to be losing synchronism for a stepping motor driven by constant-current system. A current controller 404 applies the driving-current to a stepping motor 401 in accordance with the command derived from a control unit 407. The applied current is observed by a current measuring unit 403, and stored in a current observing unit 409 in response to the sampling signals generated from a sampling signal generating unit 408. After an excitation has completed, the observing waveform is compared with a predetermined reference waveform in the control unit, and it is determined that a loss of synchronism occurs in the stepping motor when these do not agree within a predetermined tolerance.
Claims22
A controller for a stepping motor comprising:
- a stepping motor driving means for applying exciting pulses to the exciting coils of the stepping motor;
- a current measuring means for measuring a current though the exciting coils of the stepping motor in response to the exciting pulses derived from said stepping motor driving means;
- a sampling command generating means for generating sampling command every predetermined fixed period while said stepping motor driving means is applying a exciting pulse;
- a current waveform observing means for fetching and storing the exciting current measured by said current measuring means every time a sampling command is generated by said sampling command generating means;
- and
- a determining means for determining that the stepping motor has lost synchronism when the current waveform observed by said current waveform observing means does not agree with a predetermined reference waveform within a predetermined fixed tolerance after a exciting pulse has been derived from said stepping motor driving means.
Dependencies are inferred from the claim text.