SpotOn 35650, Product Manual, Page: 4 / 36

INSTRUCTIONS IN ENGLISH
| QUANTUM PAR LIGHT METER
2
UNDERSTANDING COSINE RESPONSE (SUN ANGLE EFFECT):
This meter is designed to accurately display light intensity readings +/- 80° from vertical. As
illustrated in Fig. 2, less light is hitting your crop as the light source (sun) is tilted from vertical.
This is called cosine effect and is accurately measured by the specially shaped diffuser on the top
of the light sensor. Ideally a horizontally projected light source should show no available light for
your crop regardless of its intensity. Conversely, a directly overhead light source will have 100%
of its light available for your crop.
Vertical Light
Full Light Available to Crop
Fig. 2 - Cosine Effect
Same Light at an Angle
Only a Portion of Light Available
FEATURES:
• Provides accurate PAR light readings from ANY light source:
- Full sun to full shade indoors or outdoors.
- Artificial light sources (LED, High Pressure Sodium, Metal Halide, Florescent, Halogen...).
• Three modes of operation:
- Instant Spot Measurement mode for PAR light readings.
- Scan mode for quickly averaging PAR over an area.
- DLI mode shows Daily Light Integral on the LCD (no computer needed).
• Compact and easy to use.
• Integral mounting plate for: stand, stake, lanyard & hanger hole, and magnet mounts.
• Small size allows light readings in tight spaces without needing an external sensor.
• ¼-20 threaded hole for mounting on camera tripods & stands.
• Water and impact resistant.
• Includes sensor cover & soft carrying case.
1 YEAR WARRANTY: This product is warranted to be free from defects in materials or
workmanship for one (1) year from the date of purchase.
Light
Crop
Crop
Light
SpotOn® Quantum PAR Light Meter Item #35650