Cumulus Support

At 07:30 this morning my data file showed a jump in the sun hours from 0.0 to 49.0
It has continued to add 49 to all readings since then: these readings are all reasonable (apart from the 49!)
I am using Instromet on Cumulus 1.9.4 (1097)

Any ideas?

Sunshine hours on Instromet works rather like a rain gauge, in that the station supplies a counter which just keeps increasing. As with rain, Cumulus has to remember the value of the counter at the start of the day, and subtract that from the counter that it reads from the station, to give today's figure.

Either the counter jumped up by 49 for some reason, or Cumulus got a lower figure than expected, reset the start of day counter to compensate, and then subsequently returned to normal, with the result that all subsequent figures are too high. If the latter has occurred, there will be a message that the sun hour counter has been reset in the diags file current at that time. If you zip up the diags folder and attach it, I can take a look.

To correct today's figure, you can stop Cumulus and edit today.ini. Find the [Solar] section, and within that the "SunStart" figure. Add 49 to that figure. If you want to correct the entries in the July log file, you can do that in a text editor while Cumulus is stopped. A description of the log file format is in the wiki - http://wiki.sandaysoft.com/a/Monthly_log_files - field 23 (numbering from zero) is the one you want.

Thanks Steve.
There was a reset at the offending time.
I have added 49 to the sun start value ie it is now 0.xxx
Regards
John

Had Cumulus for a long time now and I still haven't figured out the Sunshine Data use. Do I need to have a specific station? How would it know when the sun is shining and when its cloudy?

You need a station which has a solar sensor; from the solar reading Cumulus can work out whether it's sunny or not and calculate hours of sunshine.

Of the stations which work with Cumulus, Fine Offset make a station which has a solar sensor - the model numbers tend to start with a '3' - and Davis do an optional solar sensor for their stations. Instromet stations have optional solar sensors, and the station supplies sunshine hours directly.

Cumulus also works with the separate Blake-Larsen sunshine recorder.