the MAX485 and several chips need wait 25ms to enable the Receiver output
I tried use several librarys
That's bollocks in itself, possibly a requirement of a particular protocol but nothing to do with the MAX chips or RS-485.
What libraries? Are we talking Modbus or just generic comms libraries?
Do you have to use Modbus, or was that just the last thing you tried?
I think you should use "XOR" to get the value. I'm also working on some kinda of the same project, that use RS-485Hope the Info can help.‚
If you have to conform to an existing protocol (like ModBus) then you have to implement the same checksum/CRC algorithm that they use. If not then you can DIY and XORing is a nice simple thing to do.
I don´t know if can publish marks
Looks like you have to hit Google a lot.