Apogee, a manufacturer of light meters for agriculture and horticulture, launched the “Daily Light Integral” and photoperiod meters in early February 2022.
They are called the DLI400, DLI500, and DLI600.
The DLI meters measure and record daily light sum and photoperiod (light cycle).
For this purpose, the DLI meters have a display and an internal memory (99 days).
The meters can be easily placed near plants on a pole or, for example, on a photo tripod.
The recording capacity is 99 days for light sum and photoperiod. Once the DLI is started, the meter runs continuously for approximately 60 days. After that, the battery can be replaced and the measurement continues.
A 30-minute average of the last 30 days can be read via the display. The entire memory can be downloaded via a USB port (USB-C).
The DLI-400 measures the daily light sum (PAR) [µmol/m².s] plus the photoperiod (daytime).
This sensor is calibrated with sunlight (370…650 nm).
The DLI-500 measures the total daily light sum [mol/m².d] and the light cycle (daytime).
This sensor is calibrated for the full PAR spectrum (389…692 nm).
Like the DLI-500, the DLI-600 measures the total daily light sum [mol/m².d] and the light cycle, but is based on the also recently released ePAR sensor (383…757 nm).
