💬 Building a wired RS485 sensor network

[hypnosiss]

@cabat thank you. I have losts when number of messages are sent from HA to nodes(throught mqtt ethernet gateway) and in the same time nodes are sending messages to controller as well. I described issue on Home Assistant forum but without any response - https://community.home-assistant.io/t/lost-messages-sent-simultaneously/363904

[JeeLet]

yes it's not easy, the loss of package is a difficult thing to
to counter, but not entirely.
and the multiple layers of a computer system do not help :)

some philosophy on collision avoidance
https://arduino.stackexchange.com/questions/24523/rs485-multimaster-communication-with-collision-avoidance

don't mix the Protocol (data encapsulation)
and the physical support (voltage frequency impendance / star or serial bus)

the ModBus protocol on a RS485 support
https://www.electroniclinic.com/arduino-modbus-rs485-arduino-rs485-master-and-slave/

a different explanation https://www.codrey.com/learn/rs-485-arduino-quick-primer/

for information
https://github.com/sonyarouje/Arduino_HardwareSerial_RS485

But the best solution (reliability and especially lightness of the sketch) is the CAN bus :)

I may have said some stupid things ;)

Translated with www.DeepL.com/Translator (free version)

[JeeLet]

a line of the examples given in the sketches for the use of RS485 can be a source of problem
(it's my case, I use Pin2 or3 for a long time :( )

...
// Define this to enables DE-pin management on defined pin
#define MY_RS485_DE_PIN 2
(2 or 3 is an interrupt pin for a Uno)
...

avoided interrupt pins.

the pin 10 is a good thing :)

[hypnosiss]

Thank you @JeeLet !
I've been struggling with missing msgs for years with my Arduino Mega
I changed pin and no issues! :D
In the pjon code I've reached to list of tested pins that communication works properly
https://github.com/gioblu/PJON/blob/38e36bb1228c1690143cfbf693a0bcb809514d6c/src/strategies/OverSampling/README.md?plain=1#L12