[GreggWardNZ]

The VP1 switch is closed, the Rx unit is being run off an external power supply, the port name in use is /dev/ttyUSB0, which is what I had updated it to in my Cumulus.ini. One thing I cannot confirm, until I get home, is whether the "ComportName=/dev/ttyUSB0" line is duplicated in the Cumulus.ini file. Are you saying that is shouldn't be duplicated in there?

Hi,

I'm just trying to guess what can be the problem...

If your board is a v4.xx please check also this setting in your user configurable options. The default value is 5. If your RX board is a v4.xx change it to 4, and program the Arduino Nano again. After that, please do a factory reset, pressing the push button for 5 seconds.

Code:

// --------------------------------------------------------------------------------------
//   Hardware settings
// --------------------------------------------------------------------------------------
// ---- Define your RX board, main version number
#define Board_Version    5     // 6 for all RX boards v6.xx, 5 for all RX boards v5.xx, 4 for all RX boards v4.xx

My board was a v4.xx board, so I changed Board_Version to 4 and re-programmed the Nano. This fixed the problem whereby it was not seeing the EEPROM values and weewx started working.

However, CumulusMX still failed to connect to the WeatherDuino. I decided to ditch my v1 based Cumulus.ini and used the CumulusMX web interface to re-enter the settings and re-create Cumulus.ini. On restart of CumulusMX, it connected straight away to the WeatherDuino. I am now back up and running.

Again, thanks for the help.