JPS6468043A - Two-wire type information transmission equipment - Google Patents

Abstract

PURPOSE:To exactly and efficiently collect operational information from each slave station for every slave station by identifying a down signal from the master station to a slave station and an up signal from a slave station to the master station by means of a communication protocol. CONSTITUTION:In the master station 10, the following three are provided: a power supply circuit 18 to transmit a power supply pulse signal to the slave station 11, a slave station designating circuit 19 to transmit a slave station designating pulse signal coded for a group of plural slave stations which has a peak value different from that of the power supply pulse signal, and a reception circuit 20 to receive a response pulse signal from the slave station 11. In the slave station 11, the following are provided: signal selecting means 55, 56, a power supply receiving circuit 58 to store power supply pulse signals as power, a self-address decision circuit 59 to decided whether a pulse signal is a pulse that designates self-station or not, a response gate control circuit 60 to transmit the operational information of the self-station when a self-station- designating pulse signal is decided on, and a transmission circuit 63 to transmit a response pulse signal to the slave station 10. As a result, operational information from the slave station 11 can be exactly and efficiently collected in the unit of each slave station 11.