Weird serial issues

General
1

Hello! I am pretty new to Node-RED and I am working on a project that involves a bit of serial communication between a RPi 3B and several ESP32 devices over USB. The ESP32's are connected to things like relays and when something like "Pin 18 ON" is sent, the device turns that Pin on and the relay is activated.

I am having a whole load of really weird issues using the serial port nodes though, just a quick idea of what I am seeing:

Serial Out nodes showing as "connected" but when sent a command, nothing happens.
Serial Out nodes randomly timing out and I have to restart all the flows to get it to connect again.
This weird issue where the same controller shows different statuses in the same flow:

Screenshot 2025-05-02 140042
Screenshot 2025-05-02 140042586×623 31.6 KB

Is there something I can do to figure out what is causing this and stop it from happening? I've tried looking at the logs, but nothing shows up there other than the initial connections, even when I have it set to "trace"

node.js version: 20.19.2
Node-RED version: 4.0.9

2

I'm not sure I've understood your environment properly:
how many rs232-usb converters are connected to your Pi3?
which UART are you using?
are you using Esphome? if so, have you remembered to disable logs on the esp32 serial port?

by the way, you can simplify your flow by pointing to a single "Controller A (Relays" node) with "link out" and "link in" nodes, which will be easier to read :wink: