phelix avatar image
phelix asked

Driver issue reading RS485 Modbus RTU with Node-RED

Hello together,

I am trying to connect a rs485 Modbus RTU Generator to Node-RED large image 2.82 via the FTDI-USB-Serial cable. I have the node-red-contrib-modbus palette installed and downgraded node.js to version 12.22.12. and use the Modbus-Flex-Getter and debug node.
Sometimes values are transmitted, but most of the time errors or empty string is given back.
The debugging node in Node-RED prints following:



When debugging via SSH (DEBUG=contribModbus*,modbus-serial node-red -v) the following messages are received:


I have followed the howto

The ID was set to FT232_USB_UART_modbus in ft_prog, then added to the file etc/udev/rules.d/serial-starter.rules with "modbus" as VE_SERVICE.

serial-starter seems still to change drivers and baudrate each few seconds when grepping for the port:

1664973056948.pngIs there a easy option to set a fixed baud rate for a device (FT232R_USB_UART_modbus:9600) without interrupting the communication to the Carlo Gavazzi energy meter or writing a new dbus Driver ?

Or is there a better solution to read Modbus RTU values in Node-RED with the Cerbo GX?

kind regards and thanks in advance :)

cerbo gxNode-REDrs485driver
1664972581352.png (34.3 KiB)
1664972611156.png (40.6 KiB)
1664972956911.png (208.0 KiB)
1664973056948.png (560.9 KiB)
1664973757341.png (72.9 KiB)
2 |3000

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

0 Answers