💬 Building a wired RS485 sensor network

[ArduiSens]

@Flyer said in 💬 Building a wired RS485 sensor network:

ng to build

Hi Flyer, As far as I know this is not possible.

[cabat]

@Flyer Do you can ping the gateway on it IP?

[ArduiSens]

I see there is a possibility the combine Ethernet with RS485.
Maybe you can check the setup as they did here:

https://www.openhardware.io/view/649/RS485-Ethernet-Gateway#tabs-comments

https://github.com/feanor-anglin/GetWired-Project/blob/master/GetWired Ethernet Gateway/Gateway.ino

[gryzli133]

You can also try using PJON - it has solved all the issues that I was facing with RS485 and other wired solutions (like all sensors on the Gateway). It will be released officially in MySensors 2.4.0, but you can test is already now (alpha):
https://github.com/tekka007/MySensors

You can read more here:
https://github.com/mysensors/MySensors/pull/1278

[cabat]

@gryzli133 I have a number of MySensors devices using RS485, it would be interesting to try to run PJON protocol over RS485, it seems like there is such an opportunity, but I could not figure out how to use it in the MySensors library.

[hypnosiss]

yes, I am interested too as mysensors sometimes lost messages over rs485.

[cabat]

@hypnosiss you may be interested in this https://forum.mysensors.org/topic/11814/rs485-transport-ack-support/6

[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