The Lascar EL-GFX-2 standalone USB data logger measures and stores over 250,000 temperature and humidity readings over a -30°C to +80°C (-22°F to 176°F) and 0 to 100%RH range at a resolution of 0.1°C and 0.1%RH. Using the Windows control software (available as a free download from www.easylogusb.com), users can quickly set up the data logger and view downloaded data by connecting the device to the PC's USB port using the supplied cable.
The data logger features a high-contrast graphic LCD and three-input buttons. This allows users to start, stop and restart the data logger using on-screen menus. This menu also provides real-time analysis of data either as a data summary (showing highest and lowest readings and alarm conditions) or as a graph that updates as new data is added. Multiple data logging sessions can be stored on the device ready for upload to a PC at a later date.
The data logger's robust design provides IP-67 waterproof protection and the two replaceable ½AA batteries typically allow logging for up to one year. Applications include: Pharmaceutical fridge monitoring, transportation, food and drink, building and site monitoring, HVAC.
-30°C to +80°C and 0 to 100% RH measurement ranges
Logging rates between 10 seconds and 1 hour
Immediate, delayed, push-button or temperature/RH triggered start mode
Graphic LCD shows real-time readings, graph and current status
I've been using three of these little units to monitor my greenhouse 'thermal recovery system'. The downloadable software makes configuration very easy, and I can track temperatures inside and outside the greenhouse with good accuracy over long periods. They're also handy for checking what your central heating's doing in various parts of the house when you're not using them for anything else. You configure them from a PC, then unplug them and put then anywhere you need them, where they'll happily collect data for months without human intervention.
They're weatherproof, so one can safely be left outside (mounted on the garden shed using the supplied clip in my case). The supplied software is very easy to use and reliably differentiates between different sensors, provided that you give them different names when configuring them. The software remains unfazed by swapping sensors without doing any form of USB disconnect other than pulling the plug out.
On downloading data (via USB) from the logger, the software provides a graph of the temp, dew point and humidity for the recorded period. Each can be deselected from the graph if not required, but the scales are automatic, which can make it difficult to visually compare results from different sensors as each graph may have different scales.
It would be nice if the software would do a combined graph from more than one sensor (it doesn't), but as the data are stored as a .csv file (by default in your documents folder, with a filename generated from the name you gave the sensor and the date), it doesn't take too much work to import them into a spreadsheet to produce a graph of results from multiple sensors.
It would also be nice if the sensors had an on/off switch to preserve the batteries when not in use. The battery cover has to be unscrewed and one battery removed (or a bit of card inserted between the battery and its contact) to prevent drain, although the non rechargeable lithium batteries give a long life even if left running. Rapid stock suitable replacements.
All in all an excellent little unit if you need to record temperature, and/or humidity and/or dew point.
