Modbus rtu with rs485

Dear all
I'm using Siemens plc s7 1200 and I need to implement a modbus server with RS485 to connect sensors to the plc so please if any one can help me to implement this board.
thank you

I think you need a Modbus master, not modbus slave/server.

Sensors are almost always Modbus slaves (RTU RS-485)or servers (TCP ethernet).

If your sensors are like everyone elses, then you need a Modbus Master/client in the PLC to talk to the Modbus slaves.

Modbus slaves can not talk to Modbus slaves. No way. No work-around. They're dumb and silent unless spoken to my a Modbus master.

I'm a Modbus guy, not a Siemens guy. A Siemens guy will have to help you with details.

The plc acts as Modbus RTU master device.
what i need it is how to implement a modbus slave board with rs 485 communication

Go to the Siemens automation support site.
Search for entry id 47756141

Its all there, amazing what a little effort can find.

please Mike_RH
can you send me the URL

Here you go...

How do you establish a MODBUS-RTU communication with STEP 7 (TIA Portal) for the SIMATIC S7-1200?

Also have a read here starting on page 619...

S7-1200 Programmable controller System Manual

Regards,
George