Solar Radiation Monitor for PV

Photovoltaic Insolation Monitor

Eliminates waste of approximately 2%

Maximizes the power generation

Lowers running cost

Utilized as a reference for the power generated by solar panels

Brings changes to the business management of soler power generation 

A newly developed tool for insolation measurement with the same structure as solar cell modules.

An alternative to the pyranometer

Insolation measurement with the same structure as solar cell modules.

Accurate monitoring of power generation

Eliminates the error of approximately 2%. Further improves the accuracy of the business.

Early detection of the solar panel deterioration

Accurate measurement of the generated power enables the effective assessment of solar panel performances. 

Streamlines the on-site maintenance management

The simultaneous aquisition of temperature data reduces the time, cost and manpower required for the maintenance.

No need to install or maintain thermometers

Dual roles as insolation monitor and thermometer.Also for improving the accuracy of measurement.

The monitoring of the generated power by IoT is also materialized.

IoT and cloud monitoring system to be available (planned).

Solar Radiation Monitor for PV

Eliminates measurement errors of approximately 2%, to accurately monitor the amount of the generated power.

Photovoltaic insolation monitor is a new tool developed for the measurement of insolation, with the same structure as solar cell modules, based on the technologies for environmental measurement and optical instruments of Ishikawa Trading.

It can be used as an alternative to the conventional pyranometer.

By eliminating the error of approximately 2%, normally experienced in the measurement by a pyranometer, this tool very accurately captures the amount of the generated power and supports the high-precision operation of the solar power business.

Elimination of measurement error of approximately 2% experienced in the conventional methods

In the measurement of the amount of solar power generation, the conventional pyranometer has an error of approximately 2%.

The reasons for this can be attributed to the facts that insolation measurement tools other than the meteorological pyranometer did not exist and that rigorous measurment was not coducted for the evaluation of power generation. 

Even a slight error can create an enormous loss, if multiplied by the large generated power and the long operating years.

Photovoltaic insolation monitor brings a solution for this issue and support a high-precision business operation.

High-speed response

The conventional pyranometer produces a large error in the evaluation of the solar power generation, since it has a slow response (the blue line in the figure) even if a high-precision type is used.

Since the photovoltaic insolation monitor has the same output characteristics as solar panels, it can accurately measure the generated power, with high-speed response (the red line in the figure). 

Excellent spectral sensitivity characteristics

Since the response of the conventional pyranometer has flat spectral sensitivity characteristics for all wavelengths (the red line in the figure), a wavelength range that the solar modules do not generate electricity is also included in the output, which leads to a large error in the measurement of power generation.

Since the photovoltaic insolation monitor has the same spectral sensitivity characteristic as the solar panel (the green line in the figure), the accurate amount of the generated power can be captured.


No need to install or maintain thermometers

The photovoltaic insolation monitor has a built-in temperature sensor.

Since this unit by itself conducts measurements of the insolation and the temperature directly beneath the panel, simultaneously and on the same location, the more accurate meteorological data can be captured, thus creating higher precision in the data aquisition of the generated power.

In addition, the cost and labor for installing and maintaining the pyranometer and thermometer separately are no more needed.


Solar Radiation Monitor for PV

Effective for the deterioration checks and maintenance of solar panels

Panel deterioration by aging is accurately captured.

The lowering of generated power due to the solar panel deterioration by aging or damage can be identified any time by comparing the power generation from the photovoltaic insolation monitor and that from the solar panels in operation.

Panels, generating power lower than the standard, can be smoothly identified, thus contributing to the reduction of power generation losses and to the optimization of generation capacity.

Reduction of the time, cost and manpower for on-site maintenance

The photovoltaic insolation monitor, with its built-in thermometer, enables the aquisition of temperature data, simultaneously with the power generation measurement. 

It eliminates the need for man-power and time to carry or set up multiple instruments for panel maintenance, thus enhancing the efficiency of on-site maintenance.

Examples of major usages

Unmanned monitoring on large-scale sites

24-hour real-time monitoring of the whole site can be enabled by placing the monitors in key points.

No need to deploy personnel.

Usable for portable operations

Particularly for small-scale sites.

Also useful as an emergency tool, in the event of natural disasters or panel failures. 


Solar Radiation Monitor for PV

IoT and cloud system for power generation monitoring (planned).

We propose a system for the age of big-data and IoT.
  • Enables an accurate business forecast 

    Error of 2% is eliminated.

  • Supports timely maintenance

    Big data analysis enables real-time identification of the deterioration and breakdown.

    As a result, timely maintenance is enabled, eliminating the waste such as periodic maintenance.

  • Enables efficient operation of solar panels

    Visualization is available for panel replacement criteria.

    Panel operation efficiency can be optimized, in support of stabilized business management.

  • Automated monitoring to support streamlining of the management

    Unmanned monitoring is enabled, 24 hours a day and every day of the year.


Shinkawa 4-6-10, Mitaka-shi, Tokyo, 181-0004 Japan






Phone: 042-244-5501
Fax: 042-249-3831


〒181-0004 東京都三鷹市新川4丁目6-10

〒305-0035 茨城県つくば市松代4丁目5番31

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