Delta OHM LPUVB02 UVB Radiometer User Manual

: June 5, 2024
: Delta OHM

Table of Contents

INTRODUCTION
WORKING PRINCIPLE
INSTALLATION
ELECTRICAL CONNECTIONS
MEASUREMENT
MAINTENANCE
TECHNICAL SPECIFICATIONS
SAFETY INSTRUCTIONS
ACCESSORIES ORDERING CODES
References
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Operating manual
UVB Radiometer
LPUVB02

www.deltaohm.com
Keep for future reference.

INTRODUCTION

The LPUVB02 radiometer measures the global irradiance in the UVB spectral range on a flat surface (W/m 2 ). In particular, the instrument spectral sensitivity is centered at 304 m with a 5 nm bandwidth (FWHM – Full Width at Half Maximum).
The global irradiance is the sum of the direct solar irradiance and the sky diffuse irradiance on a surface parallel to the ground. Unlike the visible spectrum, where the direct component prevails over the diffuse component, in the UVB spectral region, the light is strongly diffused by the atmosphere and thus the two components are equivalent;
therefore it is of primary importance to measure both the components accurately.
The probe is typically used in the following fields:

Monitoring the ozone layer. The radiation around 295…315 nm is strongly absorbed by ozone located in the stratosphere, therefore each small variation of the ozone layer responds to an increase or decrease of the UV radiation reaching the ground.
Effects of UVB radiation (the most harmful to human health) on living beings.
UVB radiation measurement in workplaces.

The radiometer requires an external power supply.
The radiometer is manufactured to operate for long periods without maintenance (if powered correctly). This characteristic makes it suitable for use in meteorological stations.
A Pt100 temperature sensor is placed inside the radiometer in order to control its temperature. Internal temperature must remain within the specified operating range, otherwise, measurements could be affected by systematic errors higher than those stated. Exposure to temperatures higher than +60 °C can alter the interferential filter spectral characteristics.

WORKING PRINCIPLE

The LPUVB02 radiometer is based on a solid-state photodiode whose spectral response was adapted to that desired by using special interferential filters. In particular, the used photodiode and filters have exceptional stability characteristics, both in temperature and over time. This allowed the manufacturing of an instrument that does not need heating, thus reducing energy consumption.
Particular attention has been given to filter design so as to make the instrument completely blind to wavelengths outside the pass-band of interest. The solar energy within the 302 nm – 308 nm spectral band is only 0.01% of the total energy from the sun reaching Earth’s surface.
The relative spectral response curve is shown in Fig. 2.1 (in linear scale) and Fig. 2.2 (in logarithmic scale).

The LPUVB02 is provided with a 50 mm external diameter dome in order to supply suitable protection of the sensor to the weather agents. Quartz was chosen due to its optimum transmission in the UV range. The response in accordance with the cosine law has been obtained thanks to the particular shape of the diffuser and of the housing.
The deviation between the theoretical response and the measured one is shown in Fig. 2.3.

The excellent relationship between the response of the radiometer and the cosine law al- lows using the instrument also when the sun has a very low raising (the UVB diffuse radiation increases as the sun moves away from the zenith, therefore the error on the direct radiation, due to the imperfect response according to the cosine law, becomes negligible on the measurement of the global radiation).

INSTALLATION

Before installing the radiometer, refill the cartridge containing the silica- gel crystals. Silica gel absorbs humidity in the dome chamber; in case of particular climatic conditions, this humidity can cause condensation on the internal side of the dome and then modify the measurement. Do not touch the silica gel crystals with your hands and do not wet them while refilling the cartridge. Carry out the following instructions in an environment as drier as possible.

Loosen the three screws that fix the white shade disk.
Unscrew the silica gel cartridge using a coin.
Remove the cartridge perforated cap.
Open the sachet containing the silica gel (supplied with the radiometer).
Fill the cartridge with the silica-gel crystals.
Close the cartridge with its own cap, paying attention that the sealing O-ring is properly positioned and undamaged.
Screw the cartridge to the radiometer body using a coin.
Check that the cartridge is screwed tightly (if not, the silica-gel life will be reduced).
Position the shade disk and tighten it with the screws.
The radiometer is ready for use.

The following picture shows the operations necessary to fill the cartridge with the silica-gel crystals.

The radiometer must be mounted in an easy-to-reach location in order to clean the dome regularly and carry out maintenance. At the same time, make sure that no buildings, constructions, trees or obstructions exceed the horizontal plane where the radiometer lies. If this is not possible, select a site where obstructions in the path of the sun from sunrise to sunset do not exceed 5 degrees of elevation.
The radiometer must be located far from any kind of obstruction, which might reflect sunlight (or sun shadow) onto the radiometer itself.
For fixing, use the holes on the radiometer body (remove the shade disk to access the holes and reposition it after mounting) or the suitable accessories (see the figures below). In order to allow accurate horizontal positioning, the radiometer is equipped with a leveling device: the adjustment is made by means of the two leveling screws that allow adjusting the radiometer inclination. The mast height does not exceed the radiometer plane to avoid measurement errors caused by any reflection or shadow of the mast itself.
It is preferable to thermally insulate the radiometer from its mounting bracket ensuring, at the same time, good electrical contact with the ground.

ELECTRICAL CONNECTIONS

LPUVB02 has an 8-pole connector and uses the CPM12AA8U… optional cables.
The metallic housing of the radiometer should preferably be grounded ( ) locally. In this case, do not connect the wire of the cable corresponding to the housing to prevent ground loops.
Only if it is not possible to ground locally the metallic case of the radiometer, connect the wire of the cable corresponding to the housing to the ground.
The radiometer has two analog outputs: one for temperature, normalized 0…1 V corresponding to -40…+60 °C, and one for UV irradiance, not normalized corresponding to S V/(Wm -2 ), where S is the radiometer sensitivity.
The radiometer has to be connected to a power supply (7…30 Vdc) and instruments with voltage input as shown in fig. 4.1. The load resistance of the instrument reading the signal must be ≥ 10 kΩ.

Connector	Function	Color
1	Analog outputs ground (SGND)	Red
2	+Vout UV	Blue
3	Not connected
4	Cable shield (SH)	Shield
5	Power supply negative (GND)	Brown
6	+Vout Temperature	White
7	Housing (C)	Black
8	Power supply positive (+Vdc)	Green

MEASUREMENT

Each radiometer is distinguished by its own sensitivity (or calibration factor) S expressed in V/(Wm -2 ) and shown in the label on the radiometer (and in the calibration report). The irradiance Ee is obtained by measuring with a multimeter the output voltage Vout UV (difference of potential between +Vout UV and SGND) and applying the following formula:
Ee = Vout UV / S
where:
Ee is the irradiance expressed in W/m 2;
Vout UV is the difference of potential expressed in V measured by the multimeter;
S is the sensitivity of the radiometer expressed in V/(Wm -2 ).
It is possible that an offset of some tenths of millivolts (0.3 – 0.4 mV) be present on the output signal. In this case it is recommended that the data be acquired also at night and subtract the night-measurement offset from the performed measurements.
In the presence of a possible offset OFS (in Volt), the previous formula becomes:
Ee = (Vout UV – OFS) / S
Typically, the radiometer output signal, when exposed to the sun, does not exceed 1 V. In order to fully exploit the radiometer features, the readout instrument should have 0.1 mV resolution.
The temperature T in °C is obtained by measuring with a multimeter the output voltage Vout Temp (difference of potential between +Vout Temp and SGND) and applying the following formula:
T = (100 x Vout Temp) – 40
For example, suppose to read a voltage Vout Temp = 0.532 V, from the previous formula we obtain that the radiometer internal temperature is:
T = (100 x 0.532) – 40 = 13.2 °C
Notes on the radiometer calibration:
The calibration factor of the radiometer is factory-determined by measuring the output signal when the radiometer is hit by a parallel and homogeneous beam of light over the entire surface of the diffuser. Calibration is performed with monochromatic light at 304 nm.
Currently, no international calibration standards for this type of radiometer exist; therefore, the calibration coefficient only makes sense if the procedure followed to obtain it has been specified. The user has to consider that the same radiometer calibrated with different procedures can have different sensitivity factors, as explained in the article “Source of Error in UV Radiation Measurements by”, T. C. Larason, C. L. Cromer issued in the “Journal of Research of the National Institute of Standards and Technology” Vol. 106, Num. 4, 2001 (The article is available free of charge on the NIST web site at the following address: https://nvlpubs.nist.gov/nistpubs/jres/106/4/j64lar.pdf).

MAINTENANCE

In order to grant measurements high accuracy, it is important to keep the glass dome clean. Consequently, the more the dome will be kept clean, the more measurements will be accurate.
You can wash it using water and standard paper for the lens. If necessary, use pure ETHYL alcohol. After using alcohol, clean again the dome with water only.
Because of the high-temperature changes between day and night, some condensation might appear on the radiometer dome. In this case, the performed reading is highly over-estimated. To minimize the condensation, the radiometer is provided with a cartridge containing desiccant material (silica-gel). The efficiency of the silica-gel crystals decreases over time while absorbing humidity. Silica-gel crystals are efficient when their color is yellow, while they turn white/translucent as soon as they lose their efficiency. Read instructions in chapter 3 about how to replace the silica-gel crystals. Silica gel’s typical lifetime goes from 2 to 6 months depending on the environment where the radiometer works.
To exploit all the radiometer features, it is highly recommended that the calibration be checked annually.

TECHNICAL SPECIFICATIONS

UV MEASUREMENT

SAFETY INSTRUCTIONS

General safety instructions The instrument has been manufactured and tested in accordance with the safety standard EN61010-1:2010 “Safety requirements for electrical equipment for measurement, control and laboratory use” and has left the factory in perfect safety technical conditions.
The instrument’s proper operation and operating safety can be ensured only if all standard safety measures, as well as the specific measures described in this manual, are followed.
The instrument’s proper operation and operating safety can be ensured only in the climatic conditions specified in this manual.
Do not use the instruments in places where there are:

Corrosive or flammable gases.
Direct vibrations or shocks to the instrument.
High-intensity electromagnetic fields, static electricity.

User obligations
The instrument operator shall follow the directives and regulations below that refer to the treatment of dangerous materials:

EEC directives on workplace safety.
National law regulations on workplace safety.
Accident prevention regulations.

ACCESSORIES ORDERING CODES

LPUVB02| Amplified radiometric probe for outdoor use for measuring IRRADIANCE in the UVB spectral range. Supplied with shade disk, silica-gel cartridge, 2 spare sachets, bubble level, 8-pole M12 connector, and Calibration Report.
---|---
Accessories CPM12AA8U…| 8-pole cable. 8-pole M12 connector on one end, open wires on the other end. available length 2 m (CPM12AA8U.2), 5 m (CPM12AA8U.5) or 10 m CPM12AA8U.10).
LPS1| Only attachment bracket, suitable for a mast with diameter 40…50 mm. Installation on the horizontal or vertical mast.
LPSP1| Spare shade disk.
LPSG| Cartridge to contain desiccant silica-gel crystals, complete with Oring and
cap. Spare part.
LPG| Pack of 5 sachets of silica-gel crystals. Spare part.
LPS6| Kit for the installation of the radiometer. The kit includes: a 750 mm mast, base fitting, graduated support plate, and bracket for the radiometer.
LPRING02| Base with leveling device and adjustable holder for mounting the radiometer in an inclined position.

DELTA OHM metrology laboratories LAT N° 124 are ISO/IEC 17025 accredited by ACCREDIA for Temperature, Humidity, Pressure, Photometry / Radiometry, Acoustics, and Air Velocity. They can supply calibration certificates for the accredited quantities.
NOTE: ……………………………………………………………………………
EU DECLARATION OF CONFORMITY
Delta Ohm S.r.L. a socio unico — Via Marconi 5 — 35030 Caselle di Selvazzano — Padova — ITALY
Document-No. / Month. Year: 07.2019
We declare as manufacturer herewith under our sole responsibility that the following products are in compliance with the protection requirements defined in the European Council directives:
Product Description: LPUVB02
Product identifier : Radiometro UVB UVB radiometer
The products conform to the following European Directives:

Directives

2014/30/EU| EMC Directive
2014/35/EU| Low Voltage Directive
2015/863/EU| RoHS

Applied harmonized standards or mentioned technical specifications:

Harmonized standards

EN 61010-1:2010| Electrical safety requirements
EN 61326-1:2013| EMC requirements
EN 50581:2012| RoHS

The manufacturer is responsible for the declaration released by:
Johannes Overhues
Amministratore delegato Chief Executive Officer
Caselle di Selvazzano, 19/07/2019

This declaration certifies the agreement with the harmonization legislation mentioned, contained however no warranty of characteristics.
WARRANTY
Delta OHM is required to respond to the “factory warranty” only in those cases provided by Legislative Decree 6 September 2005 – n. 206. Each instrument is sold after rigorous inspections; if any manufacturing defect is found, it is necessary to contact the distributor where the instrument was purchased from. During the warranty period (24 months from the date of invoice) any manufacturing defects found will be repaired free of charge. Misuse, wear, neglect, lack or inefficient maintenance as well as theft and damage during transport are excluded. Warranty does not apply if changes, tampering, or unauthorized repairs are made on the product. Solutions, probes, electrodes, and microphones are not guaranteed as improper use, even for a few minutes, may cause irreparable damages. Delta OHM repairs the products that show defects of construction in accordance with the terms and conditions of the warranty included in the manual of the product. For any dispute, the competent court is the Court of Padua. The Italian law and the “Convention on Contracts for the International Sales of Goods” apply.
TECHNICAL INFORMATION
The quality level of our instruments is the result of continuous product development. This may lead to differences between the information reported in the manual and the instrument you have purchased. In case of discrepancies and/or inconsistencies, please write to sales@deltaohm.com. Delta OHM reserves the right to change technical specifications and dimensions to fit the product requirements without prior notice.
DISPOSAL INFORMATION
Electrical and electronic equipment marked with specific symbols in compliance with the 2012/19/EU Directive must be disposed of separately from household waste. European users can hand them over to the dealer or to the manufacturer when purchasing new electrical and electronic equipment, or to a WEEE collection point designated by local authorities. Illegal disposal is punished by law. Disposing of electrical and electronic equipment separately from normal waste helps to preserve natural resources and allows materials to be recycled in an environmentally friendly way without risks to human health.

GHM GROUP – Delta OHM | Delta Ohm S.r.l. a socio unico
Via Marconi 5 | 35030 Caselle di Selvazzano | Padova | ITALY
Phone +39 049 8977150
Fax +39 049 635596
www.deltaohm.com
sales@deltaohm.com