对于目前某些特殊设备只配备RS-422或LVDS串口而没有以太网口的情况,上位机与它们之间的数据透传只能依靠串口转换器实现,例如Moxa Uport系列USB转串口转换器等。这样的数据透传方式不仅传输距离近、效率低、成本高,而且不能够接入网络。针对这些问题,提出了一种基于LwIP TCP网口-串口数据透传设备设计方案,该数据透传设备使用ZYNQ-7020 SoC作为主控芯片设计了RS-422接口电路和LVDS接口电路,实现了网口数据与RS-422/LVDS串口数据的透传,最后在某地检设备上进行性能测试。测试结果表明该数据透传设备的RS-422和LVDS串口可实现在2 Mb/s以内的任意速率下无丢包、无误码的数据透传功能,为网口与串口之间的数据透传提供了一种可靠的实现方案。

For some special devices only equipped with RS-422 or LVDS serial port without an Ethernet port,the data transparent transmission between the upper computer and they can only be realized by the serial port converter on the market,such as Moxa Uport series USB to serial port converter.This data transparent transmission mode not only has short transmission distance,low efficiency,high cost,but also cannot access the network.To solve these problems,a design scheme of TCP netword-serial data transmittal device based on LwIP is proposed.The data transmittal device uses ZYNQ-7020 SoC as the main control chip to design RS-422 interface circuit and LVDS interface circuit,which realizes the transmittal of network data and RS-422/LVDS serial data.Finally,through the performance test carried out on a certain inspection equipment,it is proved that the serial ports of RS-422 and LVDS of the data transparent transmission equipment can realize the data transparent transmission function without packet loss and error at any rate less than 2 Mb/s,which provides a reliable implementation scheme for the data transparent transmission between the network port and the serial port.