
Сообщение от
https://www.modbus.org/file/secure/modbusprotocolspecification.pdf;стр.7
4.4 MODBUS Addressing model
The MODBUS application protocol defines precisely PDU addressing rules.
In a MODBUS PDU each data is addressed from 0 to 65535.
It also defines clearly a MODBUS data model composed of 4 blocks that comprises several elements numbered from 1 to n.
In the MODBUS data Model each element within a data block is numbered from 1 to n.
Afterwards the MODBUS data model has to be bound to the device application (IEC-61131 object, or other application model).
The pre-mapping between the MODBUS data model and the device application is totally vendor device specific.