Title:
Modbus_over_serial_line_V1_02
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Description: This document describes the MODBUS over Serial Line protocol. MODBUS Serial Line protocol is a Master-Slave protocol. This
protocol takes place at level 2 of the OSI model.
A master-slave type system has one node (the master node) that issues explicit commands to one of the "slave" nodes and processes
responses. Slave nodes will not typically transmit data without a request from the master node, and do not communicate with other
slaves.
At the physical level, MODBUS over Serial Line systems may use different physical interfaces (RS485, RS232). TIA/EIA-485 (RS485)
Two-Wire interface is the most common. As an add-on option, RS485 Four-Wire interface may also be implemented. A TIA/EIA-232-
E (RS232) serial interface may also be used as an interface, when only short point to point communication is required. (see chapter
"Physical Layer")
- [modbusM16] - modbus RTU source code with atmel avr mc
- [RS485(full).Rar] - a foreigner writing RS485 serial communi
- [modbus_sim] - Simulator for Modbus slaves over RS232/R
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Modbus_over_serial_line_V1_02.pdf
