Research Of Universal Long-Distance Display LED Screen Based On RS485 Communication

This paper aims to study on remote data display in LED screen based on RS485 communication, the research related to design of Printed Circuit Board on Single chip microcomputer(SCM),the software program design,SCM serial communication,RS485 universal transmission protocol design,RS485 interface circuits design, anti-interference and improving the stability of measures when data transmission and LED display circuit design. Meanwhile, the paper also completed the communication between SCM and XK3101 weighing instruments, the weighing sensor of electronic balance connected with the weighing instrument, the real-time data was transmitted to SCM by the RS485 bus, and then display synchronous and accurate data in the LED large screen by SCM processing.And large screen realize the general data display of different weighing instrument based on the Lab VIEW program written by the host computer. This thesis is a practical application project, according to most of remote data LED display screen of weighing instrument use 20mA current loop as communication interface in the current domestic, This transmission mode is influenced by the transmission distance, Long distance transmission leading to the attenuation of current will cause the data display inaccurate and it is need to be compensated.But because of the protocol restriction of RS485 serial communication,The large display screen using RS485 communication interface can only display the certain types of weighing instrument’s data,so the generality is not good.The screen introduced in this topic use RS485 communications.It have overcome the disadvantages of 20mA current loop communication.This paper put forward new ideas and practices in anti-interference circuit of RS485 and the program design of serial communication on the general display of large screen, further discussion and reflection on the research method of this topic.The experimental results show that the weighing instrument can synchronously transmit remote weighing data to the LED screen by the RS485 bus, but the operation of SCM and the large screen are, still very stable. It can be proved that the research and system design is in a right direction, achieving the purpose of project.Firstly,I introduce the development status of RS485 communication and the display of LED screen and also introduce the significance of the present research in this paper.Then I describe the system from hardware and software design ideas in detail based on the needed function of system. Finally, I do a further study on the realization of the universal display of large screen based on the Lab VIEW program on the host computer,...