Pyranometer (PYR-BTA)
Specifications and User Guide

-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.

What is the conversion from lux to W/cm2 ?

-order code: PYR-BTA
-Resolution, 10-bit (CBL or CBL 2): 1.2 Watts/square meter
-Resolution, 12-bit (LabPro, Go! Link, ULI, or Serial Box): 0.3 Watts/square meter
Irradiance Range: 0 to 1100 Watts/sq meter (in full sun)
Absolute Accuracy: ±5%
Repeatability: ±1%
Long-Term Drift: Less than 3% per year
Cosine Response:
45º zenith angle 1%
75º zenith angle ±5%

The sensing unit is an Apogee,SP-110 , 5-volt pyranometer.

Wavelengths Covered: 370 nm to 1140 nm
Current draw: 300 µA
Sensor Dimensions: 2.4 cm diameter by 2.75 cm height
Materials: Anodized aluminum with cast acrylic lens
Operating Environment: -25 to 55 C
0 to 100% relative humidity
Designed for continuous outdoor use
Sensor can be submerged in water. The black electronics box should be kept dry.

-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 it. One is to compare with another Pyranometer. Another is the Clear Sky Calibration method. In this method you need a sunny day with no clouds or pollution. You use a web site to calculate the expected irradiance using data entered into a web application. The latitude, longitude, time of day, etc are entered and an expected irradiance number is obtained. You can compare this with your Pyranometer reading. This procedure should be done at several different times. If the readings are consistently off, contact Vernier S&T. Debris on the Pyranometer lens is a common cause of low readings. Salt deposits can accumulate on the sensor from evaporation of sprinkler irrigation water and dust can accumulate during periods of low rainfall. The details of this Clear Sky Calibration procedure are in the Pyranometer booklet.
– Calibration information for PYR-BTA:
Sensor ‘Pyranometer’
Equation: Linear
y = bx + a
a: 0
b: 250

This sensor is great for use with current and voltage probes in solar energy studies with small solar cells (with dimensions of a few centimeters on a side).
Name Order code
For experiments with small solar cells
Current Sensor (max current 0.6 A) DCP-BTA
Differential Voltage Probe (max V=6V) DVP-BTA
Voltage Probe (max V=10V) VP-BTA

For experiments with large solar panels with dimensions greater than 30 cm or so): High-Current Sensor (max current 10 A) HCP-BTA
30-Volt Voltage Probe (max V=30V) 30V-BTA