Cumulus Support

If you have a WeatherLink data logger & a USB connection from your Davis console to your PC & you run Cumulus, then you will have installed the Silicone Labs CP210xUSB to UART Bridge, which will convert it to a serial port type connection.

I am using Windows 7 Home Premium & selecting Control Panel, then Device Manager you will see Ports (COM & LPT). Double click on this & it will show a list, double clicking the Silicon Labs CP210xUSB to UART Bridge will open a window, click on Port Settings & reset the Bit Rate per second to 19200, was most likely 9600. Select OK & close the windows as usual. Incidentally the Silicon Labs CP210xUSB to UART Bridge will also show which COM port is being used as well, could be handy if you need to know in the future.

I have found this dramatically speeds up the download time when starting Cumulus as I don't run Cumulus 24/7 & usually only have my computer on for an hour or 2 each day. It also speeds up downloading to WeatherLink as well as I run both programs at different times.

Incidentally the Baud rate setting for the Data logger is 19200 which is usually set automatically when the Console detects the WeatherLink data logger installation.

I'm surprised that it works at all with 9600, as Cumulus tells the Davis DLL to use 19200. But I'll admit my knowledge of serial port comms is limited. If Cumulus is set to 19200, and the console is set to 19200, how does that work if the serial port itself is set to 9600?

steve wrote:I'm surprised that it works at all with 9600, as Cumulus tells the Davis DLL to use 19200. But I'll admit my knowledge of serial port comms is limited. If Cumulus is set to 19200, and the console is set to 19200, how does that work if the serial port itself is set to 9600?

Hi Steve. I can't help you there either, but changing the baud rate in Device Manager certainly does make a difference. I assume that Windows sets them all at 9600 as I have checked some others on my PC & they are all 9600. I suppose the 9600 setting in Windows acts as a bottle neck but doesn't block it completely, so hence setting it to 19200 speeds up transfer.

It's is a wonder Davis & others haven't recommended changing it as well.

Regards.
Bligh.

Whilst device manager may show the baud rate at 9600, the software (Cumulus/Weatherlink) will AFAIK control the actual baud rate. The data would be pure garbage at 9600 and the software would not recognise the station.