Modbus TCP strange addresses format

Good evening,

I'm trying to use an application made in vb.net and connect my PC to a Modbus server. I have a WinCC project which successfully connects to this Modbus server and reads data. The problem is that I haven't programmed the WinCC project and I am no expert of Modbus.

I do not understand how the address format works. I have some addresses on the WinCC project, as shown in the left side of the attachment, and the configuration for the connection to the Modbus server is shown in center of the attachment. But I don't understand what 3xecc means in the WinCC addresses.

So my question is:

what START and QUANTITY should i put in the fields of the Visual Studio app (shown in the right side of the attachment) in order to read the same data as WinCC?

Thank you!

Note:

I'm using the EasyModbus library available as .NET library.

Hello;

Modbus was developped by Modicon (now a property of Schneider) in 1979. It was actually the first industrial network for PLC communication. And it uses Modicon register addresses (000001for output bits,100001 for input bits, 300001for input registers,  40001 for "holding" registers) which Siemens has retained in their Modbus drivers.

Our friend smiffy has written an excellent introduction to Modbus RTU in the following link (addressing of registers does not change for Modbus TCP), study the pdf in the first 

https://support.industry.siemens.com/forum/ca/en/posts/modbus-general-description/66876

If you have more concerns once you have read this article, come back and we will try to help you out.

Hope this helps,

Daniel Chartier 

So, if I understand correctly, if we look at the attachment of my first post and take one of the addresses (eg. 3x11.3), this means that this particular address refers to an input register (3x) and it's address is at byte 10, on the third bit?

Is it right?