XAR-P10 Quantum PAR Meter

XAR-P10 Quantum PAR Light Meter

The light that drives photosynthesis in plants is Photosynthetically Active Radiation or PAR light and is typically defined as total radiation across a range of 400 to 700 nm. PAR is universally quantified as Photosynthetic Photon Flux Density (PPFD), the sum of photons in units of micromoles per square meter per second. The XAR-P10 Quantum PAR Light Meter is designed to measure PAR flux.

XAR-P10 is ideal for gardeners, agronomy application measuring PPFD. Typical applications include measurement of incident PPFD on plant canopies in outdoor environments or in greenhouses and growth chambers, and reflected or under-canopy (transmitted) PPFD measurement in the same environments. 

Features

Provides accurate PAR light readings from full sun to full shade indoors or outdoors and artificial light sources (LED, High Pressure Sodium, Metal Halide, Fluorescent, and Halogen)

PAR light measuring range from 0 to 4000 umol*m-2*s-1                                        

Support three modes of operation: instant spot-check measurement mode for PAR light readings PPFD; scan mode for quickly averaging PAR over an area; DLI mode shows Daily Light Integral

Accurate and instant response

Easy to read large backlight display

Only two buttons and easy to operate

Four AA Alkaline Batteries

Application

Measurement of incident PPFD on plant canopies in outdoor environments or in greenhouses and growth chambers, and reflected or under-canopy (transmitted) PPFD measurement in the same environments

For gardeners, agronomy application measuring PPFD

Device

1.        PAR light sensor

2.        LCD display

3.        Power button

4.        Function button

DISPLAYs

PPFD Display

1.        Battery gauge

2.        PPFD value

3.        PPFD unit 

DLI Display

1.        Battery gauge

2.        DLI value

3.        DLI unit 

Sensor

The XAR-P10 Quantum PAR Light Meter consists of a handheld meter and a dedicated quantum sensor that is connected by cable to aluminum housing. Sensor consists of an acrylic diffuser (filter), and photodiode.

Daily Light Integral (DLI)

DLI is displayed in moles per square meter per day. The typical range for DLI is 3 to 26 mol*m-2*d-1. This is useful for understanding the average amount of light your crop sees in a day. One mole is equal to one million micromoles.

Each type of plant has a different DLI range for optimal growth. DLI is directly correlated with plant quality, and a minimum amount of light is required for marketable plants. Measuring DLI can guide in decisions regarding shade cloths and supplemental light.

XAR-P10 Quantum PAR Light Meter is designed for spot-check measurements, and calculation of DLI through the built-in logging feature.

Daily Light Integral Readings

The XAR-P10 Quantum PAR Light Meter takes a light reading every 3 minutes to use in calculating a 24-hour Daily Light Integral (DLI). Every 15 minutes the previous 24 hours of stored readings are used to recalculate the DLI. Readings are automatically taken whether the meter is on or off, as long as there is a battery in the meter, including after a power cycle (off and on).

Cosine Response (Sun Angle Effect)

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. Some of the radiation coming into a sensor at low angles is reflected, causing low readings. This is called cosine effect. The convex optical disc found on the sensor of this meter is designed to capture radiation at low angles and minimize cosine response errors. This meter is designed to accurately display light intensity readings ±80° from vertical.

Specifications

PAR Specification

General

MAINTENANCE

Blocking of the optical path between the target and meter can cause low readings. Occasionally, accumulated materials on the diffuser of the upward-looking sensor can block the optical path in three common ways:

1. Moisture or debris on the diffuser.

2. Dust during periods of low rainfall.

3. Salt deposit accumulation from evaporation of sea spray or sprinkler irrigation water.

Dust or organic deposits are best removed using water, or window cleaner, and a soft cloth or cotton swab. Salt deposits should be dissolved with vinegar and removed with a cloth or cotton swab. Salt deposits cannot be removed with solvents such as alcohol or acetone. These can damage the white diffuser disk. Use only gentle pressure when cleaning the diffuser with a cotton swab or soft cloth to avoid scratching the outer surface. Mild soap may be used. The solvent should be allowed to do the cleaning, not mechanical force. Never use abrasive material or cleaner on the diffuser.

Cleaning and Storage

The front panel and case can be cleaned carefully with a soft wet cloth. Allow drying completely before using. Do not use aromatic hydrocarbons or chlorinated solvents for cleaning.

Do not store the instrument where temperature or humidity is excessively high.

RECOMMENDED DLI

Generalized plant responses to different light levels

Recommended DLI for crops