The Modbus RTU protocol is implemented in the AC500 processor modules.
Modbus is a master-slave (client-server) protocol. The client sends a request to the server(s) and receives the response(s).
Available serial interfaces can work as Modbus interfaces simultaneously.
The Modbus client operating mode of an interface is set with the function block COM_MOD_MAST.
Technical data
|
Parameter |
Value |
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|---|---|---|---|
|
Supported standard |
Modbus RTU Server, Modbus RTU Client |
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|
Number of connection points |
1 client Max. 1 server with RS-232 interface Max. 31 servers with RS-485 |
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|
Protocol |
Modbus |
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|
Operating mode |
Client/server |
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|
Address |
Server only |
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|
Data transmission control |
CRC16 |
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|
Data transmission speed |
From 9,600 bits/s to 115,200 bits/s |
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|
Encoding |
1 start bit 8 data bits 1 or 2 stop bits 1 parity bit ⮫ “Configuring Modbus RTU on serial interface” |
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|
Max. cable length for RS-485 on serial interface option board used on the CPU. |
1.200 m at 19.200 baud |
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Bus topology
Point-to-point with RS-232 or bus topology with RS-485. Modbus is a master-slave protocol.