DATA TRANSMISSION SYSTEM FOR ELECTRIC AND HYDRAULIC CONTROL OF A MINE ROOFSUPPORT

摘要

A data transmission/reception system usable for bi-directional data transmission in electro-hydraulic control systems between two adjacent supports of a mine installation which each have their own transmitting and receiving stations in a control unit. Bi-directional data exchange takes place via a single wire data bus which is used for simultaneous transmission and reception and forms the summation point for adding the transmitted signals from two transmitters. Each transmitting and receiving station is provided with a subtraction circuit connected to a receiver of the respective transmitting and receiving stations and to which the transmitted signals from its own transmitter are supplied in each case at the subtraction circuit input. The other input of the subtraction circuit is connected to the bi-directional data bus. In this way, a duplex connection between the two transmitting and receiving stations is created in which the transmitted signals from one transmitter is subtracted from two-way transmissions at the associated receiver.