S7-1200 with Modbus RTU

Who simultaneously works with a large number of brands PLC and SCADA faces sooner or later with the fact that competence is not enough. Usually something does not work, but how to understand why? Where to read? Where to look? At whom to ask?
Absolutely exactly, that all the answers are there and all the manuals on the equipment have long been written, the only difficulty is that they either have no time to search for, or there is no time to read them. It is necessary that clicked on the button and here it is the result. What can I say, please forgive and accept)
In this article I will describe how I connected the S7-1200 Siemens PLC (TIA-Portal SP1) via the CM1241 communication module with the IP320 monochrome panel
Long enough, with visits, I tried to solve the issue of connection (I will not hide, my friends helped me)
1. After we inserted the communication module in the device manager, we need to set the port parameters

2. The field of this is created by the organizational unit OB100, which in the first scan cycle of the program initiates activating the communication processor and parameterizes the port

3. In the main OB 1 (here it is not so important) do a slave library poll. Call the function for the Modbus Slave (it makes the data of the DB block in the registers on the communicator's port). Addressing with 1 or 4xxxx1.

4. Analyze the information coming into the system blocks

5. The result of these actions should be the correspondence of the data displayed on the panel and those in the data block of the PLC. Indicators Rx / TX burn almost continuously, which characterizes the exchange of data packets

Reference information on configuring the Modbus RTU S7-1200 can be found on the official Siemens website or on the link below:

# S7-1200, # IP320, # exchange, # data, # Modbus, # RTU, #Modbus, #RTU, # CM1241, # TIA-PORTAL, # ARIES

Russian version


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