US 5,621,292 A · Servo amplifier and servo system which reduce cable interface

Abstract

A servo system includes a communication cable which is disposed between a servo control circuit and a servo amplifier. A feedback cable and a power cable are each connected between the servo amplifier and a servo motor. The communication cable includes a command signal line from the servo control circuit to the servo amplifier and a feedback signal line. The command signal line includes three PWM signal lines instead of six PWM signal lines through the use of inverters in the servo amplifier, ground lines, an enable signal line, and other various signal lines. The feedback signal line transmits a position feedback signal, which is sent from the servo motor via the servo amplifier, to the servo control circuit. Thus, a number of signal lines between the servo control circuit and the servo amplifier become unnecessary and are used as feedback signal lines for transmitting position feedback signals from the servo motor. Therefore, three cables which have so far been necessary to connect a uniaxial servo motor to a servo control circuit can be simplified to one cable.

Claims11

Dependent claims

A servo amplifier for driving a servo motor through a power transmitting cable by receiving a PWM command signal from a servo control circuit through a control cable, and a feedback signal from a pulse coder through a feedback cable, comprising:

a first interface connected to the control cable for communicating the PWM command signal with the servo control circuit;
a second interface connected to the power transmitting cable for communicating an amplified PWM command signal with the servo motor;
a third interface connected to the feedback cable and to the first interface for communicating a detected position of the pulse coder to the servo control circuit through the first interface and the control cable;
three PWM signal lines for transmitting the PWM command signal from the first interface to a plurality of corresponding high-side PWM control devices;
and
three inverters connected to said three PWM signal lines for inverting and transmitting said PWM command signal to a plurality of corresponding low-side PWM control devices;
wherein the high-side PWM control devices and the low-side PWM control devices communicate the amplified PWM command signal to the servo motor through the second interface.

4 more elements

A servo motor system for reducing a servo interface comprising:

a numeric control apparatus having an electrically connected servo control unit and servo interface;
a servo amplifier including:
a power control circuit electrically connected to a power supply,
a first amplifier interface electrically connected to the power control circuit, and
a second amplifier interface electrically connected to the first amplifier interface;
a servo motor unit having a first motor interface which transmits a detected position of a servo motor as a feedback signal to the second amplifier interface;
and
a cable electrically connecting the servo interface and the amplifier interface including:
a command signal line for transmitting a command signal from the amplifier interface to the servo interface, and
a feedback signal line for transmitting the feedback signal from the servo interface to the amplifier interface.

7 more elements

Dependencies are inferred from the claim text.

Servo amplifier and servo system which reduce cable interface

Life of this patent

Servo amplifier and servo system which reduce cable interface

Life of this patent

Abstract

Claims11