Abstract: In recent years, with the widespread application of Internet of Things systems in logistics, transportation, and retail fields, the next stage of the Internet of Things – the “Internet of Things” era is approaching. Traditional industries such as security control, industrial control, and medical electronics urgently require a large number of serial devices to be connected to Ethernet. The serial port networking server and system designed and implemented in this article serve as a bridge between serial devices and Ethernet, and are a cost-effective solution.

Introduction

In traditional industries, REC650 1MRK008514-AA, especially in the industrial control field, uses a large number of RS232 or RS485 serial ports to communicate with the host, such as CNC machine tools, digital water meters, digital electricity meters, and serial port terminals based on character interfaces. The main drawbacks of this type of device in serial communication are short distance and low speed, which cannot be centrally or remotely managed. The research and development of this project aims to provide a comprehensive solution for serial devices in the industrial control field to access Ethernet and the Internet. On the basis of not wasting existing device resources, industry users can seamlessly connect their existing serial devices to Ethernet and the Internet by setting up serial port networking servers, achieving centralized and remote control, and sharing host resources among all devices, greatly saving labor and time costs, and improving productivity.

2. System performance

Serial port server is a data communication product. REC650 1MRK008514-AA not only requires high hardware platform performance and low power consumption, but also extremely high stability and reliability. The machine must work continuously for 7X24 hours, and the hardware platform needs to integrate a watchdog circuit to prevent system deadlock. Structurally, it is required to be compact and aesthetically pleasing. On the software side, it is required to rely on a mature and stable operating system as the platform, customize serial port drivers and network drivers, modify hardware interrupt priority, and improve the real-time performance of the system. The system software platform needs to support TCP/IP, FTP, TELNET, and HTTP protocols simultaneously. The upper layer application core is the serial port service and network service program, which needs to design a comprehensive process communication mechanism to achieve the forwarding of serial port data to network data. It is required that each serial port works independently and does not interfere with each other. Each serial port works at a speed of 115.2KBPS without flow control. Users are required to be able to configure the parameters of the serial server through local ports, networks, web, and other means, monitor the machine’s operating status through centralized management software, and upgrade the core code. Maintenance and installation are required to be convenient.

3. Hardware design

To improve performance, in the actual design process, we need to fully control the underlying signals of the serial port and network, and improve the real-time performance of the entire system. We have chosen the X86 compatible platform RDC’s R8610 with a main frequency of Kodak 150MHz, which has a higher cost performance ratio. In addition, programming and assembly on this platform are relatively easy to learn, which can accelerate the product’s launch cycle. The main performance indicators of the hardware platform are shown in the table below:

The hardware structure diagram is as follows:

Figure 1 Hardware Platform Structure Block Diagram