my goal in simulations is to create the situation maximally similar to those at my real experiment. To make a visualization, I am adding -b illuminance measured/179 into C:DIVA/Temp/MyFileName_sky. Then I re-run *.bat file from the same directory and get visualization with required outside illuminance. BUT I also need illuminance values in the room at the same situation. I wonder how to perform in DIVA Point-in-time illuminance calculations having measured outside illuminance?
You can do the same with the illuminance calculations, but you have to read the results files yourself or 'post-process' them into DIVA results files. The *.bat file you run also will have a different name (without the img part). To read the results files is pretty straightforward: http://diva4rhino.com/user-guide/tips-and-tricks/understanding-diva...
I want to mention that your method will work, but it considers the skies as always perfectly clear (or perfectly diffuse if you use an overcast sky). If you measure outside illuminance on a partly cloudy or overcast day, your results will diverge more and more from reality.