I don't fully understand your question, but I will try to describe the XY read function.
You configure what signals you want to read with the XNet Create Session. Here you provide an array of signals you want to read. After the session has started the XNet hardware will look for CAN signals that come in, and hold them in a buffer, or a queue. Once you call the XNet Read, all the values in that buffer are returned, and the buffer is cleared. This assumes you have number to read set to -1, or unwired which is the default. If you called the XNet Read a second time immediately, the returned signal values will be empty. By that I mean the Data Array will contain the same size as the number of signals you configured to read in the Create Session. But the Timestamp, and Value will be empty. This is because the first read will return Timestamp and Values from all the previous signal values the hardware saw.
If you want to keep track of the previous values that have been read, then you need to track them and keep them in something like a shift register. Most designs have the Read function being called periodically, and then logging those new values, or appending them to the previous values with some limit on the size of the data being collected.
It seems I can only count on you, once again 😃
You reply is clear, thank you. I could do some remote control test and I see the same behaviour.