Application which require a fast response time
Why measuring fast
When measuring fast, better temporal resolution and higher accuracy can be acquired when the irradiance is variable. Compared to a slow sensor a fast response sensor has a better temporal resolution and higher accuracy if the sampling rate is set according to the response time criteria of the sensor. By increasing the sampling rate far below the reponse time of the sensor no additional information can be acquired. The slow reponse sensors will act as filter and average the any variation in the solar signal.