Question:
I have some questions relating to lighting control in DIVA:
(1) How Photosensor Controlled Dimming (in Lighting Control Groups) works. Does this follow "closed-loop proportional algorithm" and DIVA does multiple simulation in order to calculate the lighting schedule?
(2) Are all lighting control groups treated individually in DIVA?
Answer:
1. Photosensor controlled dimming works under the assumption that the dimming control has perfect knowledge of the illuminance from daylight in the space, and the light is dimmed to a fraction of its full output in order to meet the lighting target assuming a linear response. If you choose the photosensor controlled dimming without the occupancy sensor, occupants also have the option to completely turn off the light with a switch, which is sometimes confusing when you don't expect that. For example, if you have a photosensor dimmer set to 500lx, most of the time the occupant model will switch the light off at a much lower illuminance threshold. In this case, choosing the occupancy on/off sensor will give drastically different results. I hope that is clear -- there is a bit more about this on our help page on lighting controls. Also for more explicit help, the Lightswitch paper by Reinhart details the system very carefully.
Only one simulation is run to generate an annual illuminance prediction for each sensor, and the lighting schedules are created relative to that calculation and the control system(s) you choose.
2. Yes, all lighting control groups are treated individually in DIVA.