Numerical control system using I/O unit for time measurement

Patent metadata

Field	Value
Publication number	US-9377770-B2
Application number	US-201313761310-A
Country	US
Kind code	B2
Filing date	Feb 7, 2013
Priority date	Mar 19, 2012
Publication date	Jun 28, 2016
Grant date	Jun 28, 2016

Abstract

In a numerical control system in which a numerical controller and an I/O unit perform serial data communication through a communication line, a counter of the I/O unit starts time measurement with an input signal from an in-machine measurement device as a trigger and stops counting at the start of transmission of DI data. The I/O unit transmits a flag indicative of input of the input signal as a trigger and a value in the stopped counter to the numerical controller. Based on a time value measured by a timer and the counter value, the numerical controller calculates the time of input of the input signal.

First claim

The invention claimed is:

1. A numerical control system, which comprises a numerical controller and one or more I/O units connected to the numerical controller and transfers input and output signals between the numerical controller and the I/O units through serial communication,
wherein the I/O unit starts sending back to the numerical controller in the serial communication on receiving data from the numerical controller, and
each of the I/O units comprising:
a time measurement section configured to start time measurement with an input signal as a trigger; and
a serial communication section configured to transmit a flag indicative of input of the input signal and a measured value of the time measurement section at the start of sending back by the I/O unit to the numerical controller,
the numerical controller comprising:
an acquisition section configured to acquire the flag and the measured value input through the serial communication;
a timer configured to measure time; and
an input time calculation section configured to calculate the time of input of the input signal based on the time measured by the timer and the measured value acquired by the acquisition section.

2. The numerical control system according to claim 1 , wherein the input time calculation section calculates the time of input of the input signal based on a delay time of communication between the numerical controller and the I/O unit, as well as on the measured time and the measured value.

3. The numerical control system according to claim 2 , wherein the numerical controller comprises a delay time measurement section configured to measure the delay time of communication between the numerical controller and the I/O unit through the serial communication.

4. The numerical control system according to claim 2 , wherein the plurality of I/O units are connected in a chain to the numerical controller, and the input time calculation section calculates the time of input of the input signal based on the delay time of communication between any one of the I/O units and the I/O unit adjacent thereto, as well as on the measured time and the measured value.

5. The numerical control system according to claim 3 , wherein the plurality of I/O units are connected in a chain to the numerical controller, and the input time calculation section calculates the time of input of the input signal based on the delay time of communication between any one of the I/O units and the I/O unit adjacent thereto, as well as on the measured time and the measured value.

Assignees

• Fanuc Corp

Inventors

• Miyazaki Yoshito
• Ando Hiroshige

Classifications

• G05B19/414 Primary

  Structure of the control system, e.g. common controller or multiprocessor systems, interface to servo, programmable interface controller · CPC title

• G05B2219/34413

  Add time stamp to command message · CPC title

• G05B19/18 Primary

  Numerical control [NC], i.e. automatically operating machines, in particular machine tools, e.g. in a manufacturing environment, so as to execute positioning, movement or co-ordinated operations by means of program data in numerical form (G05B19/418 takes precedence) · CPC title