Block that implements the functionality of "Brightness measurement" from VDI 3813 [1, section 6.1.6, p. 14]. For semantic correctness it is specialized for outdoor illuminance.
.
"The function Brightness measurement (RA-FL section 2, column 5; informative function block Figure 7) is required for measuring the illuminance in rooms as well as for determining the illuminance of daylight. The former is used for lighting functions, whereas the intensity of daylight influences particularly the sunshading functions." [1, section 6.1.6, p. 14]