Xant <armando.este...@gmail.com> writes: > Excerpt note from WF developer: > > There are actually two sensors, each tuned to a different part of the light > spectrum, in the part we use to measure sunlight (the APDS-9200 from > Broadcom). The APDS-9200 reports “lux” (aka “brightness”) and “uv index” > directly (which must be calibrated), and we estimate solar radiation from > the brightness value assuming it’s light from the sun (ie., we know the > makeup of the full spectrum, more of less, even though we’re only measuring > radiation from a small portion of the spectrum).
That sounds pretty clear; illuminance and uv index are measured and solar radiation is estimated. > and Sensor reference: > > https://github.com/CalvEngIO/APDS-9200/blob/master/Docs/APDS-9200.pdf > > Long discussion and somehow confusing. Besides stating that WF has in fact > 2 Sensors for Radiation, UV and Illumination, the discussion of pure > "multiplier" still persists, and does not (clearly) answer the original > question if there are any difference among the 3 entities. The 3 things really are different, and you can't reliably and precisely obtain any one of them from measurements of the others. However, their point that one can estimate irradiance from illuminance by assuming the light source sunlight (clouds etc.) makes sense, and in particular if one had a data set containing values from their illuminance sensor and an irradiance sensor, one could just build a table of interpolation points. One might even be convinced that the errors are small relative to the claimed accuracy. For what it's worth, the Davis VP2+ has sensors for irradiance ("solar radiation") and UV index, and Davis does not claim to report illuminance. Points to Davis for being straightforward. -- You received this message because you are subscribed to the Google Groups "weewx-user" group. To unsubscribe from this group and stop receiving emails from it, send an email to weewx-user+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/weewx-user/rmieezjjvqr.fsf%40s1.lexort.com.
