S7 1200 Modbus TCP IP starting from OP320 display

Hi, could you please help me to understand how to read Siemens S7 1200 registers starting from the following input?
To interact with the PLC I have an OP operate panel (Xinje OP320) connected via RS 485.
I need to read the same data just quering the PLC but via standard modbus TCP IP, and for this I'm using node-red-contrib-modbus.
I've tryed several ways but nothing. The OP works correctly, and here you can see a testing page:

In this case I should use:

  • FC3 function (read holding registers) / FC4 function (read holding registers)
  • address: 172
  • quantity: 2

But I don't get any data, any errors, nothing

in order to receive some help, please share some details about your hardware configuration.
If I understand correctly, you are trying to read the PLC modbus registers via Modbus TCP/IP from your PC with Node-RED. Is that right?
Can you ping the PLC from your PC? In the PLC how is the modbus server configured? Since the RS-485 communication is working, I guess you configured a Modbus slave FB in the PLC program; for Modbus TCP you probably need a specific (different) FB.

Thanks @MountainKing91. Yes I can ping the PLC. Actually I thougth I could reach the PLC via modbus TCP but this is not correct. Yes, I can reach it via TCP but using S7 protocol, not modbus. Infact I can read and write data directly in node-red just using node-red contrib s7.
The problem is that the only information I have are the registers set in the OP operate panel, as for the above image. So I 'm trying to understand if there is a way to read/write those exact registers in order to remote the panel

In your plc program you should have the "MB_SLAVE" function block which sets up the modbus slave and all the registers. Somewhere in the plc program you should have a bunch of networks where you map specific variables to the modbus slave registers.

It all comes down to how you set up the slave, can you take a look at the plc program?

No, that's the problem. I hoped they were enough the info I had :frowning:

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