IoT Protocol -- Modbus
2021-02-20.
Category & Tags:
IoT,
Modbus,
RS232,
RS485,
RS422,
Serial,
COM,
CAN1939,
MQTT,
Emulator,
Simulator
OSI vs. Modbus Layers:
Tip:
- RS-485/RS485’s new name is EIA-485.
- UART usually (99%) means TTL in shops, not 232/485.
- DB9 physical port usually (90%) means 232 electrical signals level standards.
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.
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