Patent ID: 7940057
Filing Date: 2011-05-10
Classification: G05B,H04L

Abstract:
1. A power discontinuity detection method for detecting a power discontinuity occurring in any one of a plurality of I/O units connected serially to one another via communication lines in a master-slave fashion, respectively, to a numerical controller, so as to communicate data between I/O units and the numerical controller the method comprising steps of: detecting the power discontinuity when the power discontinuity occurs in any one of the I/O units; transmitting the detection of the power discontinuity to a front I/O unit situated immediately before a rear I/O unit which is said I/O unit where the power discontinuity occurs, at a timing different from a timing of normal data communication, in the form of a communication packet having a data pattern different from a data pattern utilized during said normal data communication; and storing the communication packet, when the front I/O unit receives that communication packet, as a power discontinuity detection information.