The Apogee Instruments’ DLI-500 is an elegant, user-friendly device designed for spot checking photosynthetically active radiation (PAR; 400-700 nm) levels. It also measures daily light integral (DLI) and photoperiod under all light sources.

• Accurate Measurement: The DLI-500 accurately quantifies the total amount of PAR incident on a plane within a 24-hour period (expressed in moles per square meter per day, mol m⁻² d⁻¹).

• Measurement Modes: The DLI-500 offers both stored data (DLI, photoperiod) and live view data (PPFD) screens.

• Influence on Plant Growth: PAR, DLI, and photoperiod significantly impact plant growth and development.

• Suitable for Greenhouses and Growth Chambers: Professionals use the DLI-500 to manage light and make informed decisions.

• Apogee Quality: Developed by Apogee Instruments’ engineering team under the guidance of Dr. Bruce Bugbee, a renowned crop physiologist, the DLI-500 sets the gold standard for measuring PAR levels.

• Ultra-Accurate Photodetector: It features the same 400-700 nm full-spectrum photodetector as the famous MQ-500 meter.

• Stability: Apogee’s research-grade sensors maintain accuracy over time (less than 2% drift per year).

• Rugged Design: IP65-rated for durability, it’s suitable for spot checks or continuous measurements.

• Complete Package: The DLI-500 package includes batteries, a carrying case, and a USB-C cable for data download.

• Calibration Uncertainty: ± 5 %

• Measurement Repeatability: Less than 0.5 %

• Measurement Range: 0 to 4000 µmol mˉ² sˉ¹

• Long-term Drift: Less than 2 % per year

• Field of View: 180˚

• Spectral Measurement Range (± 5 nm): 389 to 692 nm

• Directional (Cosine) Response: ± 5 % at 75˚ zenith angle

• Temperature Response: -0.11 ± 0.04 % per C

• Response Time: 2.5 seconds

• Measurement Frequency: 3 minutes

• Data Log Capacity: 99 days (DLI & Photoperiod), 10 days (30 min PPFD/ePPFD averages)

• Non-linearity: Less than 1 % (up to 4000 µmol mˉ² sˉ¹)

• Stored Data Resolution (PPFD): 0.1 µmol mˉ² sˉ¹ (when ≥ 1000, the screen will not display the decimal)

• Stored Data Resolution (DLI): 0.1 mol mˉ² dayˉ¹

• Stored Data Resolution (Photoperiod): 0.1 hours

• Connectivity: CSV file via USB-C data transfer

• ADC Resolution: 24 bits

• Operating Environment: -40 to 70 C; 0 to 100 % relative humidity

• Ingress Protection: IP65

• Mounting Compatibility: Brass 1/4-20 threaded mount

• Battery Life: Approximately 6 months

• 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: Assembled in the USA