For the resolution of my problem i made these things and the system is now working:
- I rechecked the needs for transmission from the slaves to master. If there is not a diagnosis by hand on going, the slave devices are not sending any messages to the master.
- For the receiving, (i dont know why but) i kept the
lines, as the DE pin not enabled. by doing this the system works as expected. I think if i remove the Serial.println lines and add delay(10) for example the system is going to work because of the flow of my code.
- For further projects, if i will need to send data in all directions i'll implement 2 max485 chips for each side, one is for sending and other for receiving.
Thank you very much for your answers.