In ob one modbus common load data block used

I don't no why can you explain

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Split from Basic questions about SIMATIC S7 1200.

I want to know about profinet and profibus modbus 

Plz help me 

Hello.

I would encourage you to do a web search on how to make a screen capture in Windows. It will help you very much for making pictures of issues you have.

Usainbolt

I want to know about profinet and profibus modbus 

Plz help me 

Siemens is the father of Profibus and Profinet. Profibus is built on RS485 hardware while Profinet is built on Ethernet hardware.

Modbus is a well known protocol (communication method) for many equipment makers. Modbus RTU is built on RS485 hardware. Modbus TCP is built on Ethernet hardware.

Wikipedia is a good web tool to supply very many technical data on each method. If there is something S7-1200 specific you have doubts on - please ask this question directly.

The S7-1200 can handle all 4 these communication methods. The communication partner you use, will tell you what is the method to use. Between x2 S7-1200 PLCs there is also other pure Ethernet methods available.

Modbus RTU and Profibus need hardware outside from the base CPU. Profibus cards are very special. Profinet, Modbus TCP and other pure Ethernet methods can use the Ethernet port that you have on the base CPU.

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