Miniature Temperature & Relative Humidity Loggers The SL54TH data logger from Signatrol (UK) is a low cost temperature & relative humidity data logger. Although the unit is only 17mm in diameter x 6mm high, the SL54TH is a self contained and self powered logger capable of recording up to 8000 data points with a battery life of typically 5 years at 10 minute intervals. The logger is fully programmable and can operate in temperatures from -20°C to 85°C and up to 100% humidity with a sample rate from 1 second to 24 hours. Read more ...