DLI-400 is an cost-effective, simple-to-use device for spot checking photosynthetically active radiation (PAR; 400–700 nm) levels and measuring daily light integral (DLI) and photoperiod under sunlight and some broadband light sources only. DLI refers to the total amount of PAR or extended PAR (ePAR) incident on a plane in a 24-hour period, expressed in units of moles per square meter per day (mol m-2 d-1). Photoperiod is the total amount of time in which PAR or ePAR is incident on a plane during a 24-hour period and is expressed in units of hours (h). PAR, DLI, and photoperiod influence plant growth and development, and they are often measured in greenhouses and growth chambers to aid in light management and decision making. The DLI-400 is a low-cost option accurate under sunlight and some broadband light sources only, but if you are looking for a model accurate under all lights, see our DLI-500 model.
Calibration Uncertainty: ± 5 %
Measurement Repeatability: Less than 0.5 %
Display Range: 0 to 4000 µmol m-2s-1
Long-term Drift: Less than 2 % per year
Field of View: 180°
Spectral Range: (± 5 nm) 370 to 650 nm 390 to 690 nm 390 to 760 nm
Directional (Cosine) Response: ± 5 % at 75° zenith angle
Azimuth Error: Less than 1 %
Temperature Response: -0.04 % per C -0.11 ± 0.04 % per C
Measurement Frequency: 3 minutes
Response Time: 2.5 seconds
Data Log Capacity: 99 days (DLI & Photoperiod), 10 days (30 min PPFD/ePPFD averages)
Non-linearity: Less than 1 % (up to 2500 mol m-2s-1)Less than 1 % (up to 4000 mol m-2s-1)
Time Accuracy: ± 53 seconds per month
Battery Type: 2 AAA batteries
Battery Life: Approximately 6 months
ADC Resolution: 24 bits
Mounting compatibility: Brass 1/4-20 threaded mount
Connectivity: CSV file via USB-C data transfer
Stored Data Resolution (PPFD): 0.1 µmol m-2s-1(when ≥ 1000, the screen will not display the decimal)
Stored Data Resolution (DLI): 0.1 mol m-2 day-1(when ≥ 1000, the screen will not display the decimal)
Stored Data Resolution (Photoperiod): 0.1 hours
Housing: ASA plastic
Ingress Protection: IP65
Operating Environment: -10 to 60 C; 0 to 100 % relative humidity -40 to 70 C; 0 to 100 % relative humidity
Dimensions: 1.91 W x 2.31 H x 0.93 D (inches)
Mass: 67 g
Warranty: 4 years against defects in materials and workmanship
Manufactured: Made in the USA
