Automatic transceiving control RS 485 communication circuit

Abstract

The invention relates to the technical field of communication circuits, in particular to an automatic transceiving control RS 485 communication circuit which comprises a communication chip RS 485, wherein the enabling end RE of the data output end R0 of the communication chip RS 485 and the enabling end DE of the data input end DI of the communication chip RS 485 are connected with a transceiving control signal end E, a delay circuit capable of leading jump signals of the enabling end RE to delay and jump signals of the enabling end DE to lower is connected between the enabling end RE and the enabling end DE, generation of a section of interference signals caused by the fact that the communication chip RS 485 receives a small section of data to be transmitted due to data transmission delay when the communication chip RS 485 is converted from the transmitting state to the receiving state is avoided. The automatic transceiving control RS 485 communication circuit is simple in structure and low in cost, needs few elements, simultaneously is obvious in effect and is not affected by data frequency.

Description

technical field [0001] The invention relates to the technical field of communication circuits, in particular to an automatic transceiver control RS485 communication circuit. Background technique [0002] The RS-485 interface has the advantages of good anti-noise interference, long transmission distance and multi-station transmission capability, so it has become the preferred serial interface. The maximum transmission distance of the interface can reach 1200 meters, and can form a half-duplex or full-duplex network, using shielded twisted pair transmission, and the interface connector adopts DB-9 9-pin socket. Allows connection of up to 256 nodes. Common RS485 communication chips have the following pins: data output terminal R0, data input terminal DI, enable terminal / RE of R0, enable terminal DE of DI, and data input and output terminals A and B. At the same time, the RS485 chip adopts the principle of sending priority , as long as the DE terminal is high level, no matter...

AI Technical Summary

Problems solved by technology

To filter out this interference signal, the effect of general capacitor filtering is not very obvious. It is often necessary to use some devices such as triodes and optocouplers, which not only greatly increases the cost, but also is affected by the optocoupler when the data frequency to be transmitted is high. and transistor switching speed limitations

Images