Sunday 15 December 2013

Points on a Curve

At the time of my last post I still had a problem with the daily weather graphs that weewx was creating. They were a series of dots, rather than a continuous line like the graphs for weekly, monthly and yearly data.

One of the beauties of weewx is its tweakability (technical term) and my first thought was I may have bolloxed up (there's another) a setting in the skin.conf file that sets how graph data is presented. Display type is set to line at a high level and you can change this for each graph if you choose; checking this showed it was set to the default. Eventually, by chance, I saw a post on the weewx User Group that explained the reason for this was too large a gap between the data updates. When I configured the Vantage Vue console I had set the archive interval to 30 minutes and this was too wide a gap to cause a line to be drawn.

Weewx offers a tool to find the current settings on the console (wee_config_vantage --info) and then to change them individually: --set-interval=SECONDS was the one I needed, where 'Seconds' was to be 600, i.e. every 10 minutes. Could I get it to work, could I buggery. Syslog told me that it couldn't talk to the console (between providing updates, proving that it could). Eventually I resorted to plugging the console into the PC, firing up Weatherlink and doing it that way. Success! The graphs starting showing a solid line, rather than individual dots.


Port Is Dead

All was well for a couple of days when I noticed at 6:30 (up early to catch a train) that the website hadn't updated since midnight. Puzzled, I logged onto the Pi that evening expecting to find that a power cut had changed the IP address of the NAS but found the Vantage Vue console had been reallocated port dex/tty/usb1, instead of /usb0. Not finding the console on the port in the weewx.conf file Weewx had sulked. I changed amended weewx.conf to look at usb1 and all was well for a while. Then everything failed again.

When I checked the syslog it seemed that the webcam was causing a problem with the USB hub and it was endlessly trying to register with the OS. Resolution? I've unplugged the bloody thing until I've time to work out why it's decided to fail after working perfectly for months.

As an aside, one of Weewx's tasks is to send data to Weather Underground. Somewhat scarily the day that Weewx had gone down I had an (automated) email from them to say that they hadn't received any data for over two hours. Once I had Weewx back up that evening I had another email to say they had started to see data again.