You are here:   HomeSupportFAQsPRR: PRR-800, PRR-2600, PUV-2500Why does my PRR-800 run slower than my PRR-2600?

Frequently Asked Question

Why does my PRR-800 run slower than my PRR-2600?

The time constant in our radiometers is defined as the “RC time constant” (http://en.wikipedia.org/wiki/RC_time_constant) — for both instruments it is 50 ms. The PRR-800 is running slower because it has more channels to sample. The channels are being sampled by an analog-to-digital converter running a new conversion every 25 μs.  Channels are sampled in order within an instrument housing, and are sampled continuously with the result averaged until it is transmitted, and then a new average starts to accumulate. So, an instrument with fewer channels will average more readings into a single report data frame than an instrument with more channels. There is buffering in the instrument so that when data is being transmitted, it is being sampled in the background for the next data frame to transmit. The maximum rate that an instrument will run is a function of the number of channels and number of instruments connected.