Hi, I'm finally connected to the device and reading the register's values.
This is what was wrong.
I had the RTU via TCP(UDP) option enabled and also noticed that there's an offset in the addresses. Where the address on the routers manual and at a computer software is 1044, at the testlamodbusscada is 1043.
Don't know if theres a way to configure this offset on the app. I tried at the server's options (Servers->TAP Server Name) but noticed that when I change the offset it resets to 0. Don't know if thats the right way to do it, I'm just guessing.