Transmission line disconnection detection method and slave station used for the method

摘要

A control/monitor signal transmission system that employs a transmission synchronization scheme in which a master station connected to a single control unit and a plurality of slave stations corresponding to a plurality of controlled apparatuses synchronize with each other through a transmission clock and data is transmitted therebetween over a common data signal line, a transmission line disconnection detection method that enables a disconnection of a transmission line to be detected precisely; and a slave station that is used for this method. A continuous pulse signal that the master station outputs to the common data signal line is provided with a management data region that includes a plurality of pulse signals and that differs from a control/monitor data region including data of a control data signal and data of a monitor data signal.

主权项

1. A slave station terminal connected to a common data signal line to which a master station is connected, the slave station comprising:
an address extraction device, the address extraction device counting pulses of a continuous pulse signal transmitted through the common data signal line using as a starting point a starting signal indicating the beginning of the continuous pulse signal, the address extraction device obtaining a control data signal at a timing when a count value matches an address of the slave station; a monitor data transmission device, the monitor data transmission device superimposing, on the continuous pulse signal, a monitor data signal as information from the slave station at a timing when the control data signal is transferred from the address extraction device; a management control data extraction device, the management control data extraction device extracting management control data superimposed by the master station on a management data region of the continuous pulse signal, the management data region being different from a region to be superimposed with the monitor data signal and including a plurality of pulse signals; a management monitor data transmission device, the management monitor data transmission device superimposing a management monitor data signal as information from the slave station in an input data period, the input data period corresponding to and having the same cycle as an output data period superimposed with a signal included in the management control data; and an individual identification data output device, the individual identification data output device obtaining address data from the management control data extraction device, and transferring, when the address data matches the address of the slave station, individual identification data of the slave station to the management monitor data transmission device, wherein the individual identification data is the matched address assigned to each slave station, and the management control data is a comparative data.