A safety switch input diagnosis device includes a circuit formed from a series connection of an emergency stop switch and a line having a resistor. A connection state of the emergency stop switch and failure modes of the lines are diagnosed on the basis of a voltage value at one end of the circuit. Consequently, an operation of the switch and failure modes of a circuit relating to the switch can be diagnosed.

A motor driving circuit includes a stepping motor driving circuit that controls driving of a stepping motor, a DC motor driving circuit that controls driving of a DC motor, and a control circuit that controls the stepping motor driving circuit and the DC motor driving circuit. The control circuit, upon accepting a driving instruction for driving the stepping motor in the middle of the DC motor driving circuit performing driving of the DC motor, stops driving of the DC motor by the DC motor driving circuit, and starts driving of the stepping motor by the stepping motor driving circuit.

A motor driving circuit includes a stepping motor driving circuit that controls driving of a stepping motor, a DC motor driving circuit that controls driving of a DC motor, and a control circuit that controls the stepping motor driving circuit and the DC motor driving circuit. The control circuit, upon accepting a driving instruction for driving the stepping motor in the middle of the DC motor driving circuit performing driving of the DC motor, stops driving of the DC motor by the DC motor driving circuit, and starts driving of the stepping motor by the stepping motor driving circuit.

A controller is provided for driving a stepper motor with a magnetic rotor and at least one coil. The controller has a power stage for supplying the at least one coil with current, at least one analog Hall sensor for providing a signal as a function of the position of the magnetic rotor with respect to the Hall sensor, and a feedback line connecting the Hall sensor with the power stage to feed the signal of the Hall sensor back to the power stage.

A controller is provided for driving a stepper motor with a magnetic rotor and at least one coil. The controller has a power stage for supplying the at least one coil with current, at least one analog Hall sensor for providing a signal as a function of the position of the magnetic rotor with respect to the Hall sensor, and a feedback line connecting the Hall sensor with the power stage to feed the signal of the Hall sensor back to the power stage.

A control device for a stepper motor drives in a 1-2-phase excitation method in response to an input of a drive signal. The control device includes a control signal generating unit and a drive signal generating unit. The control signal generating unit generates a pulsed control signal. The drive signal generating unit generates the drive signal for rotating by a predetermined step angle every time the control signal is input. The predetermined step angle is a half of a step angle of a 2-phase excitation method. The control signal generating unit configures a higher pulse rate of a first to an n-th (n is an integer equal to or more than 2 and equal to or less than 3) control signals in an activation period of the stepper motor than a pulse rate of the control signals following the n-th control signal.

A control device for a stepper motor drives in a 1-2-phase excitation method in response to an input of a drive signal. The control device includes a control signal generating unit and a drive signal generating unit. The control signal generating unit generates a pulsed control signal. The drive signal generating unit generates the drive signal for rotating by a predetermined step angle every time the control signal is input. The predetermined step angle is a half of a step angle of a 2-phase excitation method. The control signal generating unit configures a higher pulse rate of a first to an n-th (n is an integer equal to or more than 2 and equal to or less than 3) control signals in an activation period of the stepper motor than a pulse rate of the control signals following the n-th control signal.

A motor control unit having a motor structure that rotates a rotor by voltage excitation includes a photo interrupter, a slit rotation plate, a comparator, and an encoder circuit in order to obtain a position detection signal corresponding to a rotational phase of an output shaft. During a period of time from the motor stopping to the change of the output of an encoder circuit after the supply of a drive voltage waveform, a CPU supplies a drive voltage waveform that is advanced by an advance angle amount that has been set in advance to the motor, and after the change of the output of the encoder circuit, a drive signal by which the advance angle amount is controlled based on the output of the encoder circuit is supplied to the motor.

A motor control unit having a motor structure that rotates a rotor by voltage excitation includes a photo interrupter, a slit rotation plate, a comparator, and an encoder circuit in order to obtain a position detection signal corresponding to a rotational phase of an output shaft. During a period of time from the motor stopping to the change of the output of an encoder circuit after the supply of a drive voltage waveform, a CPU supplies a drive voltage waveform that is advanced by an advance angle amount that has been set in advance to the motor, and after the change of the output of the encoder circuit, a drive signal by which the advance angle amount is controlled based on the output of the encoder circuit is supplied to the motor.

An object of the present invention is to prevent unnecessary driving stop of a stepping motor. A robot arm section includes a robot arm, a stepping motor 31a, a motor driver 31b, an encoder 31c and a step-out detection section 31e. The robot arm has a joint J1. The stepping motor generates power for operating the joint. The motor driver drives the stepping motor according to a target angle. The encoder outputs an encoder pulse every time a drive shaft of the stepping motor rotates by a predetermined angle. The step-out detection section detects a step-out of the stepping motor based on the target angle and a current angle of the stepping motor that is identified based on the encoder pulse. When the stepping motor does not recover from the step-out before a predetermined grace time elapses from a time at which the step-out is detected, the motor driver stops driving the stepping motor at the time point at which the grace time elapses.