I've built an rs-485 network in my shop, so control various outlets, fans, and heaters. The network has been running wonderfully for a few months now, but for some reason node #2 has slowly started to miss messages, and when I try to add a 3rd node, the entire network shuts down.
Each node in the network is an Arduino Nano Every with a Max485 chip soldered onto a custom made circuit board. I know pins are correct, as this network has been functioning perfectly for a few months. The master node is connected to a RasPi, which sends my data to a website.
The network has a terminating resistor of 120 ohm at the master node and the last node. The master node also has bias resistors of 560 ohm from 5v to A and GND to B. I sized all these resistors based of this calculator.
The only thing that I can think may be a problem, is that I switch from 22 AWG twisted wire to 18 AWG solid wire halfway through the network. The master & first node is on the 22 AWG, the rest of the nodes are after the switch. I did this mainly because I ran out of the first wire, and had some other wire left around. I don't really understand why this would be the problem, as again it has been functioning for a few months now.
I guess my biggest question, is where can i start troubleshooting? How would I even narrow down the problem?
