A motor driving apparatus comprises a motor including a rotor that is rotatable and has a magnet whose outer peripheral surface divided in a circumferential direction is magnetized in multiple poles with alternating different polarities, and a position detecting unit having a first detecting element, a second detecting element, a third detecting element and a fourth detecting element, each of which detects a magnet pole, a driving unit that drives the motor on the basis of signals output from the first to fourth detecting elements, and a controlling unit that obtains a rotational quantity of the motor on the basis of signals output from the first and second detecting elements and that outputs a control signal of the motor to the driving unit on the basis of the rotational quantity of the motor.

A control device for a servo motor system is provided. The control device includes a segment parameter storage circuit, a velocity superposing circuit, a velocity transferring circuit and a pulse comparison circuit. The segment parameter storage circuit is electrically connected with the velocity superposing circuit and the pulse comparison circuit. The velocity transferring circuit is connected between the velocity superposing circuit and the pulse comparison circuit. The velocity superposing circuit updates a present velocity value according to a target velocity value and an increment. The velocity transferring circuit generates a PWM signal according to the present velocity value. The pulse comparison circuit transfers the PWM signal into a signal of a command pulse wave group and judges whether a pulse number of the PWM signal reaches a predetermined pulse number.

A programmable discrete input module is described. In one or more implementations, the programmable discrete input module comprises a pulse width modulation module configured to generate a pulse width modulated signal based upon an input signal and a pulse width modulation module configured to generate a demodulated pulse width signal. An isolator is configured to isolate the pulse width modulation module and the pulse width demodulation module and to generate isolated modulated pulse width signal based upon the pulse width modulated signal for the pulse width demodulation module to generate the demodulated pulse width signal. The programmable discrete input module also includes first comparator and a second comparator for comparing the demodulated pulse width signal with a respective programmable reference and a digital filter configured to filter a comparison signal output by the first comparator or the second comparator to generate a discrete input signal.