The original model of the GUV series was the GUV-511, and this was actually divided into two models, with slightly different internal electronics and different software requirements. The original model was manufactured between 1992 and 1994. These instruments have serial numbers < 9260, and use what we call the "Z8" electronics. Data is aquired using a program called DASWIN. Neither the software nor hardware is currently supported, but instruments of this vintage can still be returned for recalibration.
The second version of the GUV-511 used what we call "PRR" electronics and was manufactured up until 2003. This version is still supported by Biospherical and it uses the software product Logger.
After the successful introduction of the PRR-800 class of instruments, we introduced the GUV-2511, which incorporated the same electronics. This instrument added increased dynamic range, higher digital resolution, increased optical channel count, and is also supported by Logger.