Multiplex transmission system

Abstract

A multiplex transmission system (100) in which any (N.sub.i) of a plurality of nodes (N.sub.1 -N.sub.n) connected loop-like with a bidirectional signal transmission path (1a, 1b) and each respectively connected to control one of a plurality of units of electrical equipment is adapted for transmitting, in a given order (i), a prepared signal (A.sub.i, D) to the signal transmission path (1a, 1b) and for receiving a prepared signal (A.sub.i, D; A.sub.x, D) from the signal transmission path (1a, 1b), wherein any (N.sub.i) of the nodes (N.sub.1 -N.sub.n) has a rise-timing timer (CNT.sub.2), on which a rise-timing time interval (t.sub.i3, t.sub.i4) of a length proper to this node (N.sub.i) is set at a predetermined time point (54, 62, 71, 84, 88), and is adapted for rising to start signal transmission when the rise-timing timer (CNT.sub.2) has timed out. The signal transmission path (1a, 1b) includes a pair of signal transmission lines (1a, 1b), and any (N.sub.i) of the nodes (N.sub.1 -N.sub.n) is adapted, when this node (N.sub.i) is at the order of signal transmission of its own, for transmitting the prepared signal (A.sub.i, D) to the signal transmission lines (1a, 1b) and receiving the prepared signal (A.sub.i, D; A.sub.x, D) from one (1a) of the signal transmission lines (1a, 1b) and for checking the signal (A.sub.i ', D') as thus received with the signal (A.sub.i, D) as transmitted, to thereby diagnose for abnormality of the aforesaid one (1a) of the signal transmission lines (1a, 1b).