说明：  Modbus协议介绍 Modbus可编程控制器之间可相互通讯，也可与不同网络上的其他设备进行通讯，支撑网络有Modicon的Modbus和Modbus+工业网络.
(Modbus protocol description Modbus programmable controllers can communicate with each other, but also with other devices on different networks to communicate, support networks Modicon' s Modbus and Modbus+ industrial networks.)