System for positioning an object at a predetermined point for a digital servo device

Claim 1

A system for positioning an object at a predetermined point in a digital servo device which has a mechanical driving device, a detector for producing an A-phase signal and a B-phase which are different in phase timing to each other and which are used for detecting the amount of the operation of the driving device and for producing a Z-phase signal for detecting the origin of said detector itself, a feedback circuit, and an interface circuit, said interface circuit having a clock generator for generating two clock signals whose timings at active levels are not coincident with each other, a receiving shift-register for receiving operating command pulses in synchronization with the clock signals, a first gate circuit for producing a positive and a reverse direction command pulses A and B on the basis of both the output from the receiving shift-register and an operating direction command signal at the rising edge of the level of one operating command pulse, a pair of receiving shift-registers for receiving the A-phase signal and the B-phase signal from the detector in synchronization with the clock signals, a second gate circuit for producing a positive and a reverse direction detecting pulses C and D on the basis of the outputs from the pair of receiving shift-registers, and an AND circuit for carrying out an AND operation among the outputs from one of said pair of receiving shift-registers, the Z-phase signal and a command signal for positioning an object at a predetermined point whereby the AND circuit produces as an output a predetermined point detecting signal, the improvement comprising: a position detecting flip-flop connect to be set by said predetermined point detecting signal, the flip-flop being connected such that the positive and the reverse direction command pulses A and B are inhibited from being produced by locking the first-mentioned receiving shift-register in response to the output from the flip-flop and the feedback circuit is reset by a reset signal having a pulse width which is wide enough for obtaining a resetting condition at the start of resetting but not so wide that the next positive and reverse direction detecting pulses C and D are extinguished.

Claim 2

A system for positioning an object at a predetermined point in a digital servo device which has a mechanical driving device, a detector for producing an A-phase signal and a B-phase which are different in phase timing to each other and which are used for detecting the amount of the operation of the driving device and for producing a Z-phase signal for detecting the origin of said detector itself, a feedback circuit, and an interface circuit, said interface circuit having a clock generator for generating two clock signals whose timings at active levels are not coincident with each other, a receiving shift-register for receiving operating command pulses in synchronization with the clock signals, a first gate circuit for producing a positive and a reverse direction command pulses A and B on the basis of both the output from the receiving shift-register and an operating direction command signal at the rising edge of the level of one operating command pulse, a pair of receiving shift-registers for receiving the A-phase signal and the B-phase signal from the detector in synchronization with the clock signals, a second gate circuit for producing a positive and a reverse direction detecting pulses C and D on the basis of the outputs from the pair of receiving shift-registers, and an AND circuit for carrying out an AND operation among the outputs from one of said pair of receiving shift-registers, the Z-phase signal and a command signal for positioning an object at a predetermined point whereby the AND circuit produces as an output a predetermined point detecting signal, the improvement comprising: a position detecting flip-flop connect to be set by said predetermined point detecting signal, the flip-flop being connected such that the positive and the reverse direction command pulses A and B are inhibited from being produced by locking the first-mentioned receiving shift-register in response to the output from the flip-flop and the feedback circuit is reset by a reset signal having a pulse width which is wide enough for obtaining a resetting condition at the start of resetting but not so wide that the next positive and reverse direction detecting pulses C and D are extinguished.