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Venus OS Large Node Red USB to RS485 Issue

Hallo, ich versuche mit NodeRed (läuft auf den MP2 GX) eine RS485 Verbindung zum Soyo Source zu bauen. Am MP2 ist ein USB Hub angeschlossen, dort zwei Energiezähler.

Die Verbindung zum soyo Source möchte ich über den Node machen.

Leider funktioniert das überhaupt nicht, wenn ich also ein Strin über den ESB Port schicke z.B.: /dev/ttyUSB1 sehe ich nicht mein gesendete String sondern irgenwelceh zyklische Werte.

Hat jemanden ein Tipp für mich was ich machen/probieren könnt?


daba asked
daba edited ·

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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:


Is 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 :)

phelix asked
phelix edited ·

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