Learn the basic steps for calibrating a solar radiation sensor, from choosing a method to documenting the process, and improve your solar radiation measurement skills.

A escolha entre calibração de laboratório e calibração de campo depende das necessidades específicas do usuário e das condições ambientais em que o sensor será utilizado. A calibração de laboratório oferece alta precisão, mas pode negligenciar influências externas. Por outro lado, a calibração de campo considera as condições reais, mas pode ser suscetível a fatores ambientais. Uma abordagem combinada, quando viável, pode oferecer um equilíbrio entre precisão e relevância prática.

What is the process for calibrating a solar radiation sensor?

Solar radiation sensors are devices that measure the intensity and spectrum of the sun's rays. They are used for various applications, such as weather forecasting, climate research, solar energy production, and agricultural monitoring. However, to ensure the accuracy and reliability of these sensors, they need to be calibrated periodically. Calibration is the process of comparing the sensor's output with a reference standard and adjusting it accordingly. In this article, you will learn the basic steps for calibrating a solar radiation sensor.

1 Choose a calibration method

There are two main methods for calibrating a solar radiation sensor: laboratory calibration and field calibration. Laboratory calibration involves placing the sensor in a controlled environment, such as a solar simulator or a radiometric chamber, and exposing it to known levels of radiation. This method provides high precision and repeatability, but it may not account for the effects of temperature, humidity, and atmospheric conditions on the sensor's performance. Field calibration involves placing the sensor outdoors, along with a reference sensor that has been previously calibrated in a laboratory, and comparing their readings under natural sunlight. This method reflects the actual operating conditions of the sensor, but it may be affected by variations in weather, time of day, and location.

Add your perspective

Daniel Morais

Coordenador de Manutenção | Engenheiro de Confiabilidade | Especialista de Confiabilidade | Analista de PCM |
Report contribution
A escolha entre calibração de laboratório e calibração de campo depende das necessidades específicas do usuário e das condições ambientais em que o sensor será utilizado. A calibração de laboratório oferece alta precisão, mas pode negligenciar influências externas. Por outro lado, a calibração de campo considera as condições reais, mas pode ser suscetível a fatores ambientais. Uma abordagem combinada, quando viável, pode oferecer um equilíbrio entre precisão e relevância prática.

Translated

Like
David Mortimer

Independent Researcher
Report contribution
This is has a task required for the Olive camera based weather station which incorporates a small solar panel to measure solar irradiance. I am an independent researcher. On a clear day when the sky when there are few clouds, record the output of the panel (which is the voltage across a 1 ohm resistor). For each observation, estimate the global horizontal irradiance (W/m2). I use a model which only uses air mass as an input (Meinel formula for direct normal irradiance, own research for diffuse horizontal irradiance). A simple linear regression provides a calibration (this is 7 W/m2 per mV for the current panel). The results results are comparable to other sources of solar data. Details omitted for brevity. Hardware cost, < $20.

Like

2 Prepare the sensor and the equipment

Before calibrating the sensor, you need to prepare it and the equipment you will use. First, you need to clean the sensor's surface with a soft cloth and a mild solvent, such as alcohol or water, to remove any dust, dirt, or moisture that could interfere with the measurement. Second, you need to check the sensor's wiring and connections, and make sure they are in good condition and securely attached. Third, you need to select a suitable data logger or voltmeter that can record or display the sensor's output signal, and connect it to the sensor according to the manufacturer's instructions. Fourth, you need to set up the calibration equipment, such as the reference sensor or the solar simulator, and ensure that they are properly aligned and calibrated.

Add your perspective

Daniel Morais

Coordenador de Manutenção | Engenheiro de Confiabilidade | Especialista de Confiabilidade | Analista de PCM |
Report contribution
Preparar cuidadosamente o sensor e o equipamento é crucial antes da calibração. Limpar a superfície do sensor para remover impurezas, verificar as conexões e fiações, escolher um registrador apropriado e configurar os equipamentos de calibração são passos fundamentais. Essa etapa inicial assegura que o processo de calibração ocorra em condições ideais, maximizando a precisão e confiabilidade das medições do sensor de radiação solar.

Translated

Like

3 Perform the calibration procedure

Depending on the calibration method you chose, you need to follow a different procedure to calibrate the sensor. For laboratory calibration, you need to place the sensor in the calibration equipment, and expose it to different levels of radiation, from low to high, while recording or reading the sensor's output signal. You need to repeat this process several times, and calculate the average output signal for each level of radiation. Then, you need to plot the output signal versus the radiation level, and fit a linear or nonlinear curve to the data. The slope and intercept of this curve are the calibration coefficients that you need to apply to the sensor's output signal to obtain the actual radiation value. For field calibration, you need to place the sensor and the reference sensor outdoors, preferably on a horizontal and level surface, and expose them to natural sunlight for at least one hour, while recording or reading their output signals. You need to repeat this process at different times of the day, and calculate the average output signal for each sensor. Then, you need to plot the output signal of the sensor versus the output signal of the reference sensor, and fit a linear or nonlinear curve to the data. The slope and intercept of this curve are the calibration coefficients that you need to apply to the sensor's output signal to obtain the same value as the reference sensor.

Add your perspective

Daniel Morais

Coordenador de Manutenção | Engenheiro de Confiabilidade | Especialista de Confiabilidade | Analista de PCM |
Report contribution
O método de calibração escolhido determina o procedimento a ser seguido. Na calibração de laboratório, exposição a diferentes níveis de radiação, registro do sinal de saída e ajuste de uma curva permitem calcular coeficientes de calibração. Esses coeficientes são cruciais para traduzir o sinal do sensor em valores reais de radiação. Já na calibração de campo, a exposição ao sol natural, gravação dos sinais de saída e ajuste de uma curva em relação ao sensor de referência levam aos coeficientes de calibração. Ambos os métodos demandam rigor e repetição para assegurar resultados precisos.

Translated

Like

4 Verify the calibration results

After calibrating the sensor, you need to verify that the calibration results are satisfactory and consistent. You can do this by comparing the sensor's output signal with the reference standard or the reference sensor under different conditions, and calculating the error or deviation between them. The error or deviation should be within the acceptable range specified by the sensor's manufacturer or the calibration standard. If the error or deviation is too large, you may need to repeat the calibration procedure or check for any sources of error, such as faulty equipment, incorrect settings, or environmental factors.

Add your perspective

Daniel Morais

Coordenador de Manutenção | Engenheiro de Confiabilidade | Especialista de Confiabilidade | Analista de PCM |
Report contribution
Após a calibração, é essencial verificar a consistência e a adequação dos resultados. Isso é feito comparando o sinal de saída do sensor com o padrão de referência em diferentes condições, calculando o erro ou desvio. O valor obtido deve estar dentro do intervalo aceitável estabelecido pelo fabricante ou normas de calibração. Caso o erro seja significativo, é crucial investigar possíveis fontes, como equipamento defeituoso, configurações incorretas ou influências ambientais, podendo ser necessário repetir o procedimento de calibração para assegurar a precisão dos dados.

Translated

Like

5 Document the calibration process

The final step for calibrating a solar radiation sensor is to document the calibration process and the results. You need to record the date, time, location, method, equipment, settings, data, calculations, coefficients, and errors or deviations of the calibration. You also need to label the sensor with a calibration sticker that indicates the calibration date, the calibration interval, and the calibration authority. You need to store the calibration records in a secure and accessible place, and update them whenever you perform a new calibration. The calibration records are important for maintaining the quality and traceability of the sensor's measurements, and for complying with the standards and regulations of your field or industry.

Add your perspective

6 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?

Add your perspective

Matheus Boeira

Agronegócio | Product Line | Logística | Gestão de Projetos | Melhoria Contínua | Green Belt | PDCA |
Report contribution
Escolher um local de calibração que seja representativo das condições normais de operação, considerando a exposição solar típica.

Translated

Like

What is the process for calibrating a solar radiation sensor?

1

2

3

4

5

6

1 Choose a calibration method

2 Prepare the sensor and the equipment

3 Perform the calibration procedure

4 Verify the calibration results

5 Document the calibration process

6 Here’s what else to consider

Mechanical Engineering

Rate this article

Thanks for your feedback

More articles on Mechanical Engineering

More relevant reading

What is the process for calibrating a solar radiation sensor?

1

2

3

4

5

6

1 Choose a calibration method

2 Prepare the sensor and the equipment

3 Perform the calibration procedure

4 Verify the calibration results

5 Document the calibration process

6 Here’s what else to consider

Mechanical Engineering

Rate this article

Thanks for your feedback

Explore Other Skills