New standard gain setting applied inside the AMPBOX
Published: Tuesday, November 29, 2011
The AMPBOX is a current sink amplifier that regulates a current loop (provided by theread-out device) between 4 and 20mA, depending on the mV signal from the radiometer. Kipp & Zonen supplies two different versions of the AMPBOX. One with standard gain setting, and the other with the gain adjusted to suit a specific radiometer. The default gain setting of the standard version has been changed to 2mV/1mA for a better match with our radiometers.
The standard gain setting used to be 1mV/1mA, which means that the AMPBOX will regulate the current to 5mA when the output of the radiometer is 1mV. Due to fluctuations in the manufacturing processes of thermopiles some radiometers can supply more than 16mV at 1000-1400 W/m2. Although these instruments remain within their given specifications, the high sensitivities are causing the AMPBOX to reach its limit for the 100% span value. Especially the CMP 3 and CMP 6 detectors can have a higher sensitivity.
Also customer feedback through the http://www.kippzonen.com/support indicated the AMPBOX could run out of span. As a result of this, we have changed the default gain setting from 1mV/1mA to 2mV/1mA. This means that the AMPBOX will regulate the current to 4.5mA when the output of the radiometer is 1mV. The output is rescaled by a factor two which will prevent an AMPBOX running out of scale.
The 1mA/1mV setting can still be ordered when required. The only difference is that now this needs to be ordered as an adjusted version with 1mA/mV as the required setting.