A Modbus Protocol Stack Compatible with RTU/TCP Frames and Embedded Application

摘要

Modbus communications are carried out by different frame formats on different physical links. As a result, to use Modbus on two distinct links, it's common to design two sets of protocol stack software. In this article a Modbus protocol stack compatible with RTU and TCP frames is proposed, which can be adopted on resource-limited micro controllers to greatly reduce software size, as well as speeding the system performance. Detailed layered model, as well as function descriptions and flow charts for each layer are given. In the end, we will examine an application case based on ST Semiconductor's STM32 micro controoler. The result shows it achieves the design expectation.