IoT Protocol -- Modbus

OSI vs. Modbus Layers: Tip: RS-485/RS485’s new name is EIA-485. Modbus Protocol # See Also： 【strongly recommend！】 a nice intro to Modbus and Modbus Enron. (Simply Modbus 软件收费，但是这个 Modbus 入门文档非常好) 一文看懂 Modbus 协议 Complete Modbus Guide. a good intro to Modbus. Each Modbus Slave has 4 tables with 9999 values in each table. Coil/Register Number (//≈index) Data Addresses RW Type Table (//Abbreviation &) Name 1-9999 0000 ~ 270E Read-Write (DO) Discrete Output Coils 10001-19999 0000 ~ 270E Read-Only (DI) Discrete Input Contacts 30001-39999 0000 ~ 270E Read-Only (AI) Analog Input Registers 40001-49999 0000 ~ 270E Read-Write (AO) Analog Output Holding Registers 注意！ Output is writable, input is read-only. ...