Communication circuit, relay connecting circuit, and communication network

摘要

A communication circuit, a relay connecting circuit, and a communication network transmit/receive contact signals usable for automatic control. A transmitting section transmits a contact signal input into an input/output section to a communication line, and a receiving section receives a signal via the communication line. An input/output circuit outputs the contact signal received by the receiving section via the input/output section and performs an interlocking function to prevent input of another contact signal via the input/output section. A time division communication control section switches a communication direction among the transmission section, the receiving section and the input/output circuit at a time-divided timing.

主权项

1. A pair of communication circuits, the pair of communication circuits being connected via a single communication line, the pair of communication circuits comprising:
an input and output section for inputting and outputting contact signals via the single communication line; a transmitting section for transmitting a contact signal input via the input and output section to the communication line; a receiving section for receiving the contact signal from the communication line; an input and output circuit for outputting the contact signal received by the receiving section via the input and output section and performing an interlocking function based on the outputting of the contact signal to prevent input of another contact signal via the input and output section in a state of outputting the contact signal via the input and output section; and a time division communication control section for switching a communication direction among the transmission section, the receiving section and the input and output circuit at a time-divided timing, wherein the input and output circuit further comprises a storage section that stores contact signal state information received by the receiving section; a logical sum operating section for calculating and obtaining a use state of the communication line based on a logical sum of ON states in the contact signal state information stored in the storage section; anda switch element that connects the input and output section to the transmitting section for outputting the contact signal and preventing the input of another contact signal via the input and output section based on the use state of the communication line,
wherein the input and output circuit further comprises a token call control section configured to issue tokens whose number is in accordance with a number of input and output sections at a predetermined time, and only an input and output section with a smallest node number is a master node that issues a token call that controls operations of the other input and output sections.