ModbusRTU Slave or ModbusTCP server in C#

[AlekseyLev]

The PLC is master in Modbus RTU. It sends requests. For example: 01 05 00 0D FF 00 1D F9 (writing the 13th register to the "on"/true position). How do I see this request in c#?

[saifalkatout]

My understanding is that you are trying to sniff the packet that your application produces.

You will have to use a tool like wireshark https://www.wireshark.org/download.html , also there are older versions of Visual studio that used to have network profilers https://devblogs.microsoft.com/visualstudio/introducing-visual-studios-network-tool/.