Distributed More Based On Rs - 485 Bus Communication System Design

Whether in the field of industrial control or signal test, the achievement of data fusion which is based on different communication protocol is urgent needed. However, in the current market, protocol converter can only achieve conversion between two protocols, such as RS-485to RS-232, USB to RS-485and so on.Because of a large of cases of coexistence of multiple data bus, it has great practical significance to develop an equipment for protocol conversion among different buses.Based on the reasons above, a high-speed RS-485-based multi-bus communication system is presented in this paper. The entire system which is used to realize the three categories of bus communication protocol conversion consists of some RS-485nodes, each node contains the communication interfaces including RS-232, RS-485and USB. In the practical application, the number of nodes can be changed as required to form system, for achievement of data fusion between a variety of bus communication protocol.An ARM chip LPC1756combining with an external of UART chip SC16IS762are used in high speed RS-485circuit of this system to achieve the highest rate of5Mbps. CRC-16algorithm is added to the Bus, and a set of simple and practicable error handing mechanism is put forward to ensure the correctness of the data communication process. Virtual serial port communication which is based on USB is used between upper moniter and the protocol conversion system, therefore a serial device connection status detection and automatic initialization method is proposed in this article.The characteristic of this system is the use of the bus structure to ensure the system’s flexibility, multi-device communication interface and speed versatility of optional guarantee system, the use of the checksum algorithm and various types of anti-interference measures to ensure system reliability.