Delta OHM LPPYRA-Lite Pyranometer User Manual
- June 9, 2024
- Delta OHM
Table of Contents
- INTRODUCTION
- WORKING PRINCIPLE
- INSTALLATION
- ELECTRICAL CONNECTIONS
- MEASUREMENT
- MAINTENANCE
- TECHNICAL SPECIFICATIONS
- SAFETY INSTRUCTIONS
- ACCESSORIES ORDERING CODES
- EU DECLARATION OF CONFORMITY
- WARRANTY
- TECHNICAL INFORMATION
- DISPOSAL INFORMATION
- CUSTOMER SUPPORT
- References
- Read User Manual Online (PDF format)
- Download This Manual (PDF format)
Delta OHM LPPYRA-Lite Pyranometer User Manual
INTRODUCTION
LPPYRA-Lite pyranometer measures the irradiance on a flat surface (W/m2 ).
The measured irradiance (Global Irradiance) is the sum of direct solar
irradiance and diffuse irradiance.
LPPYRA-Lite is a Spectrally Flat Class C (Second Class) pyranometer in
accordance with ISO 9060:2018 and with the criteria of the WMO “Guide to
Meteorological Instruments and Methods of Observation’”.
The pyranometer is available in the following versions:
-
LPPYRA-Lite: PASSIVE.
The passive version can be connected to the instruments D09847 and HD31 by using VP472 SICRAM module. -
LPPYRA-Lite AC: ACTIVE with 2-wire (current loop) 4..20 mA output (0…2000 W/m2 ).
The pyranometer is supplied factory calibrated.
The calibration is carried out in accordance with the ISO 9847:1992 (type IIc)
standard: ”Calibration of field pyranometers by comparison to a reference
pyranometer”.
The pyranometer is calibrated by comparison with the reference sample
calibrated annually at WRC (World Radiation Center).
An optional fixing base integrating a levelling device is available as an
accessory, for installations where horizontal positioning is required.
WORKING PRINCIPLE
LPPYRA-Lite pyranometer is based on a thermopile sensor.
The thermopile sensitive surface is coated with a black matt paint, which
allows the pyranometer not to be selective at different wavelengths.
Radiant energy is absorbed by the thermopile black surface, thus creating a
difference of temperature between the center of the thermopile (hot junction)
and the pyranometer body (cold junction).
Thanks to the See beck effect, the difference of temperature between hot and
cold junction is converted into a Difference of Potential.
In order to grant the thermopile a proper thermal insulation from the wind and
reduce the sensitivity to thermal irradiance, LPPYRA-Lite is equipped with a
glass dome.
The dome protects the thermopile from the dust, which might change spectral
sensitivity if it lies on the black surface,
To prevent internal condensation forming on the internal side of the dome
under certain climatic conditions, silica gel tablets are inserted inside the
pyranometer to absorb humidity.
Fig. 2.1: scheme of principle LPPYRA-Lite (version with mV output)
INSTALLATION
-
The pyranometer 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 pyranometer 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. N.B.:
The presence of obstructions on the horizon line affects significantly the measurement of direct irradiance.
The pyranometer must be located far from any kind of obstruction, which might reflect sunlight (or sun shadow) onto the pyranometer itself. -
In compliance with ISO TR9901 standard and WMO recommendations, the pyranometer must be positioned so that its connector is pointed to the North Pole, if the instrument is used in the Northern Hemisphere, and to the South Pole, if used in the Southern Hemisphere.
For fixing, use the two holes under the pyranometer body or the suitable accessories (see the figures below).
In order to allow an accurate horizontal positioning, the optional LPS40/32BL fixing base integrating a levelling device can be used.
The mast height does not exceed the pyranometer plane to avoid measurement errors caused by any reflection or shadow of the mast itself. -
It is preferably to thermally insulate the pyranometer from its mounting bracket ensuring, at the same time, a good electrical contact to ground.
Fig. 3.1: dimensions and fixing holes
Fig. 3.2: fixing adapters from 40 to 32 mm holes centre distance
Fig. 3.3: fixing on HD2003.77/40 clamping
Fig. 3.4: fixing on LPS3 bracket
Fig. 3.3: fixing on LPRING04 adjustable holder
ELECTRICAL CONNECTIONS
LPPYRA-Lite has a 4-pole connector and uses the CPM12AA4… optional cables.
| The metallic housing of the pyranometer 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 pyranometer, connect the wire of the cable
corresponding to the housing to ground.
Note: in LPPYRA-Lite AC the housing is not connected to the connector.
---|---
In the powered version LPPYRA-Lite AC, internally there are surge protection
devices connected to the housing.
Grounding the housing allows the correct protection functionality, in
particular against lightning.
LPPYRA-Lite CONNECTIONS
The pyranometer LPPYRA-Lite is passive and does not require power supply.
It is to be connected either to a millivoltmeter or to a data acquisition
system.
Typically, the pyranometer output signal does not exceed 20 mV.
In order to better exploit the pyranometer features, the readout instrument
should have 1 µV resolution.
Connector | Function | Color |
---|---|---|
1 | +Vout | Red |
2 | -Vout | Blue |
3 | Not connected | White |
4 | Cable shield (SH) / Housing | Black |
Fig. 4.1: LPPYRA-Lite connections
LPPYRA-Lite AC CONNECTIONS
The pyranometer LPPYRA-LiteAC has 4…20 mA output and requires 10…28 Vdc
external power supply.
It is to be connected to a power supply and an instrument with 4…20 mA input
as shown in fig. 4.2.
The load resistance of the instrument reading the signal must be ≤ 500 Ω.
Connector | Function | Color |
---|---|---|
1 | Positive (Iin) | Red |
2 | Negative (Iout) | Blue |
3 | Not connected | White |
4 | Cable shield (SH) | Black |
Fig. 4.2: LPPYRA-LiteAC connections
MEASUREMENT
Below are the ways to calculate the global irradiance.
LPPYRA-Lite
Each pyranometer is distinguished by its own sensitivity (or calibration
factor) S expressed in µV/(Wm-2) and shown in the label on the pyranometer
(and in the optional calibration report).
The irradiance Ee is obtained by measuring with a multimeter the
difference of potential DDP at the ends of the sensor and applying the
following formula:
where:
is the irradiance expressed in W/m2 ;
is the difference of potential expressed in µV measured by the multimeter;
is the sensitivity of the pyranometer expressed in µV/(Wm-2).
LPPYRA-LiteAC
The 4…20 mA output signal corresponds to the 0…2000 W/m2 irradiance range.
The irradiance Ee is obtained by measuring with a multimeter the current
absorbed by the sensor and applying the following formula:
where:
is the irradiance expressed in W/m2;
is the current expressed in mA absorbed by the pyranometer.
MAINTENANCE
In order to grant measurements high accuracy, it is important to keep the
outer 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 papers for lens.
If necessary, use pure ETHYL alcohol. After using alcohol, clean again the
dome with water only.
To exploit all the pyranometer features, it is highly recommended that the
calibration be checked annually.
TECHNICAL SPECIFICATIONS
Sensor | Thermopile |
---|---|
Typical sensitivity | 5÷15 µV/Wm-2 or normalized 7 µV/Wm-2 |
Measuring range | 0÷2000 W/m2 |
Viewing angle | 2p sr |
Spectral range (50%) | 300÷2800 nm |
Output | LPPYRA-Lite : µV/Wm-2 (impedance 33…45 L) LPPYRA-LiteAC |
: 2-wire (current loop) 4…20 mA (RL ≤ 500 L)
Power supply| LPPYRA-Lite : passive version, no power required
LPPYRA-LiteAC : 10…28 Vdc
Consumption| LPPYRA-Lite : passive version, no power required
LPPYRA-LiteAC : equal to output signal (4…20 mA)
Connection| 4-pole M12 connector
Dimensions| Fig. 3.1
Weight| 150 g approx.
Operating temperature/humidity| -40÷80 °C / 0÷100%
Protection degree| IP 67
MTBF| > 10 years
Technical Specifications According to ISO 9060:2018
Classification | Spectrally Flat Class C |
---|---|
Response time (95%) | < 25 s |
Zero offset
- response to a 200 W/m 2 **thermal radiation**
- response to a 5 K/h change in ambient temperature
- total zero offset including the effects a), b) and other sources
| ****
<÷±20÷W/m2
<÷±6÷W/m2
<÷±30÷W/m2
Long-term instability (1 year)| <÷±2÷ %
Non-linearity| <÷±2÷ %
Response according to the cosine law| <÷±25÷ W/m2
Spectral error| <÷±2÷ %
Temperature response (-10…+40°C)| < 3 %
Tilt response| <÷±3÷ %
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 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 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
-
LPS40/32: Fixing adapter from 40 to 32 mm holes centre distance.
-
LPS40/32BL: Fixing adapter from 40 to 32 mm holes centre distance. With integrated levelling device. Accuracy of levelling device < 0.2°.
-
LPS3: Fixing bracket for the pyranometer, suitable for ∅ 40 ÷ 50 mm mast.
Installation on horizontal or vertical mast. LPS40/32… adapter is required. -
LPRING04: Adjustable holder for mounting the pyranometer in an inclined position on Ø 40 mm mast with internal thread. LPS40/32… adapter is required.
-
HD2003.77/40: Clamping for mast ∅40 mm to install the pyranometer on a transverse mast.
LPS40/32… adapter is required. -
CPM12AA4…: Cable with 4-pole M12 connector on one end, open wires on the other end.
Length 2 m (CPM12AA4.2), 5 m (CPM12AA4.5) or 10 m (CPM12AA4.10).
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.
EU DECLARATION OF CONFORMITY
Document-No. / Month. Year: 5179 / 01.2022
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 identifier: LPPYRA-Lite / LPPYRA-Lite AC
Product description: Pyranometer
The products conform to following European Directives:
Directives
2014/30/EU| EMC Directive
2014/35/EU| Low Voltage Directive
2011/65/EU – 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:
Chief Executive Officer
The 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 the 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 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 the 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 symbol in compliance
with 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 a 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.
CUSTOMER SUPPORT
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