Hi Chaveiro, I will try to help a bit. I have a topic which I am going to post a few instructions on as I also want help similar to you and in return I hope someone can help me. 
Here is the link: Modbus RTU (RS485) Instructions
Hi Chaveiro, I will try to help a bit. I have a topic which I am going to post a few instructions on as I also want help similar to you and in return I hope someone can help me. Here is the link: Modbus RTU (RS485) Instructions