I have a really similar issue (12V powered sensor + SPI-12) that I would appreciate some advice on. We want to monitor solar radiation (shortwave) under forest canopy, for which common silicon diode pyranometers (e.g. Apogee SP212) are not suitable – a thermopile pyranometer is needed. We have two options for thermopile pyranometers. 1) Apogee SP510. Self powered, output range 0-144mV. 2) Campbell Sci CS320. 6-24V excitation, SPI-12 output. We will not be using the optional 12V heater on either of these. Both sensors are actually manufactured by Apogee. I saw in another comment that the millivolt SP510 signal will be noisy with the Mayfly (an amplified version of SP510 is not available). We are working in a low light environment, so noise will be an issue. Thus, I was leaning toward the CS320 due to the SPI-12 output (hence zero logger/cable noise). But the CS320 has the same power issue as the CS451 pressure sensor mentioned above. Which would you suggest for the mayfly? Is it better to tackle the noise/signal amplification issue or the power issue?
Also, just want to say thanks for all the awesome work going on here – super exciting initiative for ecological monitoring!