This week was a milestone; all-new smart UV sensors SUV-A, SUV-B and SUV-E have been sent out to customers. The instruments are born and now available to deliver from stock.
After more than 15 years of setting the standard in UV measurements, our well-known UVS series of radiometers have been replaced with a new generation smarter than alternatives. The new SUV range has dedicated models to measure UVA, UVB and UVE (UV Index) with the latest detector technology, digital signal processing and Modbus® output.
With the launch last year also came a lot of questions. Last week I received an email from one of our distributors in South America. They forwarded us some concerns from a customer about our new UV radiometers. The fact that the SUV's are not temperature stabilized was one of the questions and the other was about the internal desiccant. Because I thought that others might have the same questions, I decided to share my response in this blog.
Benefits of the new SUV range
The old UV radiometers are referred to as UVS, the new ones are called SUV (Smart UV), both available for monitoring the UV ranges A, B and E (which stands for Erythemal, the sensitivity of the human skin). Let me explain why the new concept is really an improvement over the old one.
The concept of the old UVS used a phosphor to convert photons of UV radiation into visible light for the detector. Because the resulting light level is extremely low, it requires very high amplification. The response of the phosphor, photodiode and amplifier is temperature dependent and that is why these parts were in a cavity, temperature stabilized at 25°C.
SUV radiometers use state-of-the-art UV sensitive photodiodes and the desired spectral characteristics of the photo diode in combination with the glass or quartz dome and the quartz diffusor are achieved by a holographic UV optical filter. There is a small, but known and characterized, temperature dependency that is corrected by a 5th order polynomial in the smart electronics.
SUV radiometers use the smart electronics that have been in the field for over 10 years in our ‘S’ radiometers and come with a 5-year warranty. The sealed housing is the same as for the CMP10 and SMP10 pyranometers (and other models), the internal desiccant does not need inspection and is guaranteed for 10 years. It is replaced when a recalibration is done.
The old UVS can no longer be bought or manufactured because of obsolete components. But even if you could, I would strongly recommend using the new ones because of:
- Improved specifications
- 5-year warranty (10 years on desiccant)
- Wider operating temperature range
- Improved and proven sealed enclosure
- Quartz diffusor, so no discoloration
- Can be used with all our standard accessories, like mounting plates and the CVF4 ventilation unit
- Analog (0-1 Volt) and digital (Modbus® RS-485) outputs
- Digital data available for irradiance in W/m2, internal temperature, calibration history, serial number, power supply voltage, etc.
- The SUV consumes only 50 mW, the old UVS used up to 8W depending on the ambient temperature.
UVIATOR software to correct UV measurements
Like UVS, the new SUV's are all provided with an individual spectral calibration and corrections for changing air mass (solar zenith angle, in degrees) and total ozone column (Dobson Units, DU). This data is now supplied on a USB stick, instead of on CD-ROM. These two factors affect the radiometer response to UV radiation. We found the required correction for the new SUV to be significantly less than for the old UVS, as visualized in the graphs below for the SUV-B and the old UVS-B-T.
An improved and updated UVIATOR software will be available to correct the remaining measurement error due to solar zenith angle using the measurement location and for ozone using satellite data.
SUV, no reason for concern and lots of benefits
Allongside the DustIQ we also installed the RT1, to measure the plane of array (POA) irradiance. It also comes with a back panel temperature sensor that allows you to measure the temperature of the PV module.
As you can see both concerns are unnecessary. The temperature stabilization is no longer necessary, a lot of power is saved, and the spectral response is better. There is no need to inspect and change desiccant in an external drying cartridge, it is internal and will last up to ten years, and there is a 5-year warranty.