12.10. Example Modulating Profiles
The following are some useful formulae for modulating profiles.
ta>24 1 when ta is greater than 24, and 0 otherwise
to<26 1 when to is less than 26, and 0 otherwise
ta>20 & ta<24 1 when ta lies between 20 and 24, and 0 otherwise
ta>to 1 when ta is greater than to, and 0 otherwise
ta>=21 & to>=12 1 when ta is greater than or equal to 21 and to is greater than or equal to 12, and 0 otherwise
gt(ta,22,4) 0 when ta<20 and 1 when ta>24, with a linear ramp in between (a proportional band of width 4K between 20 and 24)
ramp(ta,20,0,24,1) an alternative to the above formula
gt(ta,to,4) rises smoothly from 0 to 1 as ta increases through to, the transition occurring over a band of 4 degrees
lt(to,18,2) & lt(to,ta,4) 1 when to<18 and to<ta, and 0 otherwise, with bands of width 2 and 4, respectively.
ramp(e1,0,1,500,.4) a formula suitable for applying as a dimming profile controlling lighting gain as a function of available daylight. It modulates the lighting gain as a function of the illuminance on the working plane, e1. The value of the profile falls from 1 at zero illuminance to 0.4 at illuminance 500 lux, thereafter remaining constant at this value. The value 0.4 (which you should set as appropriate) represents the fraction of the room’s lighting gain which is not subject to daylight control. The illuminance e1 must be computed using the link to sensors in RadianceIES.
