Pyranometer (PYR-BTA)

Specifications and User Guide

Troubleshooting

• Primary Test: Make sure that the sensor detects sunlight. A bright sunny day should approach a thousand Watts/square meter in irradiance.
• Secondary Test: If there is no sun, you can use an incandescent lamp, which should produce a couple hundred Watts/square meter at a few centimeters range. If the Pyranometer is used with artificial lighting, be aware that there may be flicker in the lamp brightness, which can cause confusing signals.

Additional Troubleshooting

• What is the conversion from lux to W/cm² ?

Specifications

• Sensing Unit: Apogee,SP-110, 5-volt pyranometer
• Irradiance Range: 0 to 1100 watts/m² (in full sun)
• Absolute Accuracy: ±5%
• Repeatability: ±1%
• Long-Term Drift: Less than 3% per year
• Cosine Response:
  ⚬ 45° zenith angle: 1%
  ⚬ 75° zenith angle: ±5%
• Wavelength range: 360 nm to 1120 nm
• Current draw: 300 µA
• Output signal: 0 to 4.4 V (dark to full sunlight)
• Typical Resolution: 0.3 Watts/m²
• Sensor dimensions:
  ⚬ Diameter: 2.4 cm
  ⚬ Height: 3.3 cm
• Materials: Anodized aluminum with cast acrylic lens
• Operating Environment:
  ⚬ –40 to 70 ºC
  ⚬ 0 to 100% relative humidity
  ⚬ Designed for continuous outdoor use
  ⚬ Sensor can be submerged in water. The black electronics box should be kept dry.
• Default calibration coefficients: Slope 250 W/m²/V; Intercept 0 W/m²

Calibration

Calibrate? No. The sensor is set to the stored calibration before shipping. If you are suspicious about the calibration, there are two ways to check.

1. Compare the readings value with another Pyranometer.
2. Use the Clear Sky Calibration method. You will need a sunny day with no clouds or pollution effects.
   1. Access the Clear Sky website where you can enter data into the web application to have the expected irradiance calculated.
   2. Input values for the calculation including latitude, longitude, altitude, time of day, day of year, air temperature, and relative humidity.
   3. You can compare the calculated irradiance with the reading on the Pyranometer.
   4. This procedure should be done at several different times. If the readings are consistently off, contact Vernier.

Note: Debris build-up on the lens of the PAR Sensor is a common cause of inaccurate readings. Salt deposits can accumulate on the sensor from evaporation of sprinkler irrigation water and dust can accumulate during periods of low rainfall.

Related Products

• PAR Sensor (PAR-BTA)
• Go Direct^® PAR (Photosynthetically Active Radiation) (GDX-PAR)
• Go Direct® Pyranometer (GDX-PYR)

Additional Products

This sensor is great for use with current and voltage probes in solar energy studies with solar cells.