Review on 📝 Enhanced Logging Format for General Tools DLM112SD by Brian Rivenbark

There weren't any reviews for it, so I went to the General Tools & Instruments website and read the manual before purchasing. Alternatives with useful logging of intensity and time data were 2-3 times more expensive. I'm satisfied so far. I've only had this device for 2 days, but it solved my problem of measuring changes in light intensity over time. This device can receive data for long periods of time in a wide range of time steps from 1 second to 60 minutes. There seems to be virtually no limit to how long data logs last unless you run out of storage (you could probably log months of data with a 16GB card and 1 hour increments). I see the change in light intensity over time. I used a standard NIST instrument with no data logging to verify the calibration of several basic photospectra. This meter arrived with an error of only 5%, which is negligible and easily corrected in the meter or data files. If you have a reference spectrometer, you can probably refer to almost any spectrum in the CIE range, as long as the spectrum of the measured light doesn't change significantly with intensity over time. I have not fully tested the limits of the wavelength range. This device responded well to 390nm LEDs and a 650nm scattered light laser, but my goal in purchasing the device was to measure broad spectrum light sources. The data is downloaded to a full size SD flash memory. The device comes with a 2GB card. It accepts up to 16GB, which would be a huge amount of data. I had some of these cards from my old Nikon cameras. It's handy to have a second card, so one card can be read and swiped while the other writes data. You can format cards in the system at any time. You can mark multiple logs or delete selected files on the system, but it's faster on a PC. The logged data is stored in an Excel file. There doesn't seem to be an easy way to change the data storage format (date/time vs luminance instead of time increment and luminance), but reformat the data on a PC using Excel and get useful data charts. This device supplies lux or footcandles. It also logs temperature vs. time data when lit, but I'll have to provide your own J or K thermocouple. I've had several thermocouples that seemed to work fine and were accurate to +/- 1 degree Fahrenheit. The ability to watch temperature versus time and light intensity is a feature I like. The device is powered by 6 AA batteries or an external 9V source. You'll need to provide your own 9V supply, but AC adapters with more than 500mA 9V DC output with several types of DC plugs to ensure you fit are cheap and plentiful. I haven't tested long-term stability yet.