Let's say I already have a tourist schengen visa which will be valid at the time of the conference, so getting another visa is not exactly desirable. I plan to pay for the conference myself and the subject of the conference is connected to my job only indirectly. However since my activity in the country could not be exactly described as a tourism, I'm curious is it really fine?

Also to expand questions further, by quick googling I couldn't find what are exact regulations of what you can and can not do with certain type of schengen visa (most of my findings are about the requirements of getting the visa), so some useful links would be appreciated.