MEDIDOR QUANTUM BASICO BQM (modelo BQM-SUN) ó (modelo BQM-ELEC) Los medidores Quantum BQM miden luz PAR (Photosynthetic Photon Flux - PPF) instantáneo en µmol m-2 s-1. Especificar calibración con luz solar o eléctrica.

MEDIDOR QUANTUM CON CONMUTADOR DE CALIBRACION (modelo QMSW) Igual que el BQM pero incluye un conmutador para cambiar entre calibración solar y eléctrica. ESPECIFICACIONES MANUAL DE OPERACIONES

 

MEDIDOR QUANTUM CON SENSOR SEPARADO (modelo QMSS-SUN) ó (modelo QMSS-ELEC) An option to the basic meter with the sensor mounted at the end of a 2 meter cable. Sensor and cable are waterproof, meter is splash-resistant.  Specify sunlight or electric calibration. ESPECIFICACIONES  MANUAL DE OPERACIONES

 

MEDIDOR QUANTUM CON CONMUTADOR DE CALIBRACION Y SENSOR SEPARADO (modelo QMSW-SS) Combina nuestras dos opciones más populares en un medidor.   ESPECIFICACIONES  MANUAL DE OPERACIONES

 

MEDIDOR DE RADIACION DUAL (modelo DRM-FQ) Measures both foot-candles and photosynthetic radiation in one meter.  We designed this meter to assist those most familiar with foot-candles who would like to start the switch to using photosynthetic photon flux (PPF).  ESPECIFICACIONES MANUAL DE OPERACIONES

CÓMO TOMAR DE MEDIDAS

Our Quantum meters offer good accuracy at a low cost, but the user should be aware of potential sources of error. The biggest error is often caused by small changes in the position of the meter. The sensor on the top of the meter must be exactly horizontal for the most accurate measurement.  The correct position for making a measurement is shown at right.

 

 UTILIZACIÓN DEL MEDIDOR

 1.  Turn the dial to the "ON" position.

 2.  Hold the meter so that the sensor surface on the top is horizontal.

 3.  Hold the meter at eye level to avoid shading the sensor with your head.

       4.  The number in the display is the PPF with units of µmol m^-2 s^-1.

 Consult us for a discussion about PPF units and conversions to different units.

 5.  Turn the meter off after use to conserve battery power.

 

 

 

 

 

 

 

 

RESPUESTA DEL SENSOR

Respuesta Espectral. An ideal quantum sensor would give equal emphasis to all photons between 400 and 700 nm and would exclude photons above and below these wavelengths. The response of such a sensor is shown in the adjacent graph below. The most accurate way to measure this radiation is with a spectroradiometer, which costs over $15,000. However, Quantum meters that approximate the ideal response with filters are commercially available for 10% of this. These meters are accurate to within about  ±3 % for common light sources.

The spectral response of the Sensor used in Quantum Meters and the Quantum Sensor is shown at right. As the figure indicates, the sensor underestimates the 400 to 500 nm wavelengths (blue light), overestimates the 550-650 wavelengths (yellow and orange light), and has little sensitivity above 650 nm (red light). Fortunately, common light sources are mixtures of colors and the spectral errors offset each other. The sensor measures green light (500-550 nm) accurately, so it can be used to measure the radiation inside and at the bottom of plant canopies.

 

                             

 

 

                                          

 

Because the spectral response of the sensor and the spectral output of electric lamps is constant, the errors under different lamp types can be calculated.

This meter is calibrated for either sunlight or electric lamps. The errors under other light sources are shown below:

 

 

RESPUESTA DEL COSENO

Some of the radiation coming into a sensor at low angles is reflected, which causes the reading to be less than it should be. To partly correct for this problem, sensors are often enclosed in a black cylinder with a small raised translucent disk in the top. This cosine corrected head helps to capture radiation at low angles. The sensor used is cosine corrected by surrounding it with a dense foam gasket that blocks the radiation at very low angles. A small gap between the edge of the sensor and the gasket allows the correct amount of low angle radiation to be captured by the sensor. The cosine error for typical applications is less than 1%.

 

RESPUESTA EN TEMPERATURA

Increasing temperature increases the output of most radiation sensors. This meter was calibrated at 20°C. It reads 0.6% low at 10°C and 0.8% high at 30°C. This temperature error is insignificant for most applications.

 

ESTABILIDAD A LARGO PLAZO

The output of all radiation sensors tends to decrease over time as the detector ages. Our experience indicates that the average decrease of the sensor in this meter is about 1% to 2 % per year. We recommend returning the meter for recalibration every 3 years.

CALIBRACIÓN 

The Quantum meter includes a potentiometer that can be used to change the calibration.
Please contact your distributor if you would like the meter recalibrated.
Do not attempt recalibration without a radiation standard.

 

RESULTADOS A LARGO PLAZO

We began a study in August 1997 to measure long term stability and sensor drift quantum sensors, pyranometers and UV sensors. The graph at the right is some of the data comparing our Quantum
sensors with the mean of 5 Li-cor quantum sensors.

 

     

 

ESPECIFICACIONES

 

 

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