Kipp Zonen CMP CMA Series Pyranometers Albedometers V1007 Manual
User Manual:
Open the PDF directly: View PDF 
.
Page Count: 36
| Download | |
| Open PDF In Browser | View PDF |
CMA series
Albedometer
CMP series
Pyranometer
Instruction Manual
IMPORTANT USER INFORMATION
Reading this entire manual is recommended for full understanding of
the use of this product.
Should you have any comments on this manual we will be pleased to
receive them at:
Kipp & Zonen B.V.
Delftechpark 36, 2628 XH Delft, The Netherlands
or P.O. Box 507, 2600 AM Delft, The Netherlands
T
F
E
W
:
:
:
:
+31 (0)15 2755 210
+31 (0)15 2620 351
info@kippzonen.com
www.kippzonen.com
Kipp & Zonen reserves the right to make changes to the specifications
without prior notice.
WARRANTY AND LIABILITY
Kipp & Zonen guarantees that the product delivered has been
thoroughly tested to ensure that it meets its published specifications.
The warranty included in the conditions of delivery is valid only if the
product has been installed and used according to the instructions
supplied by Kipp & Zonen.
Kipp & Zonen shall in no event be liable for incidental or consequential
damages, including without limitation, lost profits, loss of income, loss of
business opportunities, loss of use and other related exposures,
however used, rising from the faulty and incorrect use of the product.
User made modifications can affect the validity of the CE declaration.
COPYRIGHT© 2010 KIPP & ZONEN
All rights are reserved. No part of this publication may be reproduced,
stored in a retrieval system or transmitted in any form or by any means,
without permission in written form from the company.
Manual version: 1007
Page 1
Declaration of Conformity
According to EC guideline 89/336/EEC 73/23/EEC
We
Kipp & Zonen B.V.
Delftechpark 36
2628 XH Delft
The Netherlands
Declare under our sole responsibility that the products
Type:
CMP 3 / CMP 6 / CMP 11 / CMP 21 / CMP 22
Name:
Pyranometer
and
Type:
CMA 6 / CMA 11
Name:
Albedometer
to which this declaration relates are in conformity with the following
standards
Imissions
EN 50082-1
Group standard
Emissions
EN 50081-1
EN 55022
Group standard
Safety standard
IEC 1010-1
Following the provisions of the directive.
B.A.H. Dieterink
President
KIPP & ZONEN B.V.
Page 2
CMP/CMA series manual
Table of Contents
IMPORTANT USER INFORMATION ....................................................................................................... 1
Declaration of Conformity ......................................................................................................................... 2
Table of Contents ..................................................................................................................................... 3
1.
Introduction .................................................................................................................................... 5
2.
Installation and operation............................................................................................................... 6
2.1. Delivery .......................................................................................................................................... 6
2.2. Mechanical installation................................................................................................................... 6
2.2.1. Installation for measurement of global radiation ........................................................................ 6
2.2.2. Installation for measurement of radiation on inclined surfaces.................................................. 8
2.2.3. Installation for measurement of reflected radiation.................................................................... 8
2.2.4. Installation for measurement of diffuse radiation ....................................................................... 9
2.2.5. Installation for measurement of albedo...................................................................................... 9
2.2.6. Underwater use.......................................................................................................................... 9
2.3. Electrical installation .................................................................................................................... 10
2.4. Operation ..................................................................................................................................... 11
2.5. Measurement uncertainty ............................................................................................................ 11
2.6. Maintenance ................................................................................................................................ 13
3.
Principle components of pyranometers ....................................................................................... 14
3.1. Dome ........................................................................................................................................... 14
3.2. Detector ....................................................................................................................................... 15
3.3. Housing........................................................................................................................................ 15
3.4. Drying cartridge............................................................................................................................ 15
3.5. Cable and connector.................................................................................................................... 15
4.
Pyranometer physical properties ................................................................................................. 16
4.1. Spectral range.............................................................................................................................. 16
4.2. Sensitivity..................................................................................................................................... 16
4.3. Impedance ................................................................................................................................... 16
4.4. Response time ............................................................................................................................. 16
4.5. Non-linearity................................................................................................................................. 17
4.6. Temperature dependence ........................................................................................................... 17
4.7. Tilt error........................................................................................................................................ 17
4.8. Zero offset A ................................................................................................................................ 17
4.9. Zero offset B ............................................................................................................................... 18
4.10.
Operating temperature ............................................................................................................. 18
4.11.
Field of view ............................................................................................................................. 18
4.12.
Directional response ................................................................................................................ 18
4.13.
Maximum irradiance................................................................................................................. 18
4.14.
Non-stability.............................................................................................................................. 19
4.15.
Spectral selectivity ................................................................................................................... 19
4.16.
Environmental .......................................................................................................................... 19
4.17.
Uncertainty ............................................................................................................................... 19
5.
Calibration.................................................................................................................................... 20
5.1. Calibration principle ..................................................................................................................... 20
5.2. Calibration procedure at Kipp & Zonen ....................................................................................... 20
5.2.1. The calibration facility............................................................................................................... 20
5.2.2. Calibration procedure............................................................................................................... 20
5.2.3. Calculation................................................................................................................................ 21
5.2.4. Zero offset ................................................................................................................................ 21
5.3. Traceability to World Radiometric Reference .............................................................................. 21
5.4. Recalibration ................................................................................................................................ 21
6.
CMP/CMA models ....................................................................................................................... 23
6.1. CMP 6 / CMA 6 ............................................................................................................................ 23
6.2. CMP 11 / CMA 11 ........................................................................................................................ 23
Page 3
CMP/CMA series manual
6.3. CMP 21 ........................................................................................................................................ 24
6.4. CMP 22 ........................................................................................................................................ 24
6.5. CMP / CMA series performance specifications ........................................................................... 25
6.6. CMP / CMA series general specifications ................................................................................... 26
7.
Frequently asked questions......................................................................................................... 27
8.
Trouble shooting .......................................................................................................................... 28
Appendix I Radiometric terminology....................................................................................................... 29
Appendix II 10k thermistor specifications ............................................................................................... 30
Appendix III Pt-100 specifications .......................................................................................................... 31
Appendix IV classification According to WMO Guide 1996.................................................................... 32
Appendix V List of World and Regional Radiation Centres .................................................................... 33
Appendix VI Recalibration service.......................................................................................................... 34
Page 4
CMP/CMA series manual
1. Introduction
Dear customer, thank you for purchasing a Kipp & Zonen instrument. Please read this manual and the
separate instruction sheet for a full understanding of the use of your pyranometer or albedometer.
A CMP series pyranometer or CMA series albedometer is a high quality radiometer designed for
measuring short-wave irradiance on a plane surface (radiant flux, W/m2) which results from the sum of
direct solar radiation and the diffuse radiation incident from the hemisphere above the instrument.
According to International Standard ISO 9060 and the World Meteorological Organisation (WMO) a
pyranometer is the designated type of instrument for the measurement of global or diffuse solar
radiation. All pyranometers and albedometers within the CMP/CMA series are compliant with one of
the classes specified by the international standards.
This manual, together with the instruction sheet, gives information related to installation, maintenance,
calibration, product specifications and applications of the CMP/CMA series. Note that the smaller CMP
3 pyranometer with a single glass dome is largely excluded from this manual due to the different
construction. However, the general definitions and principles also apply to this model.
If any questions should remain, please feel free to contact your Kipp & Zonen dealer or e-mail
info@kippzonen.com
For information about other Kipp & Zonen products or to check for any update of this manual, go to
www.kippzonen.com
Page 5
CMP/CMA series manual
2. Installation and operation
2.1. Delivery
Check the contents of the shipment for completeness (see below) and note whether any damage has
occurred during transport. If there is damage, a claim should be filed with the carrier immediately. In
this case, or if the contents are incomplete, your dealer should be notified in order to facilitate the
repair or replacement of the instrument.
Contents of delivery:
1.
2.
3.
4.
5.
6.
7.
8.
Radiometer
Sun shield
Cable with connector
Test reports
Instruction sheet
Radiometer fixing kit
2 x desiccant bags
Product documentation CD
Although all CMP/CMA radiometers are weatherproof and suitable for harsh environmental conditions,
they have some delicate mechanical parts. Please keep the original packaging for safe transport of the
radiometer to the measurement site or for use when returning the radiometer for calibration.
The calibration certificate supplied with the instrument is valid for 1 year from the date of first use by
the customer, subject to the variations in performance due to specific operating conditions that are
given in the instrument specifications. The calibration certificate is dated relative to the time of
manufacture, or recalibration, but the instrument does not undergo any sensitivity changes when kept
in the original packing and not exposed to light. From the moment the instrument is taken from its
packaging and exposed to irradiance the sensitivity will deviate slightly with time. See the 'non-stability'
performance (maximum sensitivity change per year) given in the radiometer specification list.
2.2. Mechanical installation
The mechanical installation of the radiometer depends upon the measuring purpose. Different
measuring methods will be explained in the next paragraphs.
2.2.1. Installation for measurement of global radiation
The following steps must be carefully taken for optimal performance of the instrument.
1. Desiccant
Check the condition of the desiccant and replace if necessary, for example after a long storage period.
2. Location
Ideally the site for the radiometer should be free from any obstructions to the horizon above the plane
of the sensing element. If this is not possible, the site should be chosen in such a way that any
obstruction over the azimuth range between earliest sunrise and latest sunset should have an
elevation not exceeding 5o (the apparent sun diameter is 0.5o).
Page 6
CMP/CMA series manual
This is important for an accurate measurement of the direct solar radiation. The diffuse solar radiation
is less influenced by obstructions near the horizon. For instance, an obstruction with an elevation of 5o
over the whole azimuth range of 360o decreases the downward diffuse solar radiation by only 0.8%.
The radiometer should be readily accessible for cleaning the outer dome and inspecting the desiccant
It is evident that the radiometer should be located in such a way that a shadow will not be cast upon it
at any time (for example by masts or ventilation ducts). Note that hot exhaust gas (> 100oC) will
produce some radiation in the spectral range of the radiometer and cause an offset in the
measurements. The radiometer should be distant from light-coloured walls or other objects likely to
reflect sunlight onto it, or emitting short-wave radiation.
3. Mounting
The CMP pyranometer is provided with two holes for 5 mm bolts. Two each of stainless steel bolts,
washers, nuts and nylon insulation rings are provided in the fixing kit. The pyranometer should first be
secured lightly with the bolts to a solid and stable mounting stand or platform as shown in Figure 1.
After recalibration the nylon insulators must be replaced with new ones to prevent corrosion.
The mounting stand temperature can vary over a wider range than the air temperature. Temperature
fluctuations of the pyranometer body can produce offset signals, therefore it is recommended to isolate
the pyranometer thermally from the mounting stand by placing it on its levelling screws. Ensure that
there is a good electrical contact with earth to conduct away currents in the cable shield induced by
lightning.
Figure 1 Pyranometer installation
Note:
After recalibration and/or reinstallation the nylon insulators must be replaced with new ones to
maintain durability.
4. Orientation
In principle no special orientation of the instrument is required, although the World Meteorological
Organisation (WMO) recommends that the signal lead is pointed towards the nearest pole, to minimise
heating of the electrical connections.
Page 7
CMP/CMA series manual
5. Level pyranometer
Accurate measurement of the global radiation requires proper levelling of the thermopile surface. Level
the instrument by turning the two levelling screws to bring the bubble of the spirit level centrally within
the marked ring. For easy levelling, first use the screw nearest to the spirit level. When the
pyranometer is placed horizontally using the bubble level, or when it is mounted with its base directly
on a horizontal plane, the thermopile is horizontal within 0.1o.
6. Secure pyranometer
Secure the pyranometer tightly with the two stainless steel bolts. Ensure that the pyranometer
maintains the correct levelled position!
7. Fit cable and sun shield
Locate the cable plug correctly in the radiometer socket (it only fits one way) and screw the plug
locking ring hand-tight. Finally, clip on the sun shield to prevent excessive heating of the radiometer
body. The bubble level is visible through the top of the sun shield for routine checks.
2.2.2. Installation for measurement of radiation on inclined surfaces
It is advised to pre-adjust the levelling screws on a horizontal surface for easy orientation of the
instrument parallel to the inclined surface. Because the temperature of the mounting stand is expected
to rise considerably (more than 10oC above air temperature), the body must be thermally isolated by
the levelling screws from the stand. This will promote a thermal equilibrium between domes and body
and decrease zero offset signals.
2.2.3. Installation for measurement of reflected radiation
In the inverted position the pyranometer measures reflected
global radiation. According to the WMO the height should be 1
m to 2 m above a uniform surface covered by short grass.
The mounting device should not interfere significantly with the
field of view of the instrument. The upper plate prevents
excessive heating of the pyranometer body by the solar
radiation and, if large enough, it keeps the lower screen free of
precipitation. The lower glare screen prevents direct
illumination of the domes by the sun at sunrise and sunset and
is available as an accessory kit for the CMP series.
Offset signals generated in the pyranometer by thermal effects
are a factor of 5 more significant in the measurement of
reflected radiation due to the lower irradiance level. The mast
shown in Figure 2 intercepts a fraction D/2SS. of the radiation
coming from the ground. In the most unfavourable situation
(sun at zenith) the pyranometer shadow decreases the signal
by a factor R2/H2.
Figure 2 Mast construction
A rule of thumb is:
A black shadow with radius = 0.1 H on the field below decreases the signal by1% and 99% of the
signal will originate from an area with radius 10 H.
Page 8
CMP/CMA series manual
2.2.4. Installation for measurement of diffuse radiation
For measuring sky radiation, the direct solar radiation is
intercepted by a small disk or sphere. The shadow of the disk
must cover the pyranometer domes completely. However, to
follow the sun's apparent motion, a power-driven tracking device
is necessary as shown in Figure 3.
This can be done using a Kipp & Zonen sun tracker, such as the
model 2 AP, designed to track the sun accurately under all
weather conditions. More information about the combination of
pyranometer and tracker is given in the sun tracker manual.
Alternatively, a static shadow ring can be used to intercept the
direct solar radiation; but it is less accurate and may require
periodic manual adjustment. At times the shadow ring also
intercepts a proportion of the diffuse sky radiation. Therefore,
corrections for this to the recorded data are necessary.
Figure 3 2AP Sun Tracker with
shaded pyranometer
Kipp & Zonen produces a universal shadow ring, model CM 121, which is suitable for use at all
latitudes. In the CM 121 manual, installation instructions and correction factors are given.
2.2.5. Installation for measurement of albedo
An albedometer measures both the global solar radiation and the
reflected radiation form the surface below. It can be configured
from two CMP series pyranometers and a suitable mounting
plate, or by using a CMA series integrated albedometer.
The requirements for installation of the upper and lower
pyranometers are the same as in paragraphs 2.2.1 and 2.2.3 for
global and reflected radiation. A typical arrangement is shown in
Figure 4. According to the WMO the height should be 1 m to 2 m
above a uniform surface covered by short grass.
Installation of the CMA series differs slightly because there are
no levelling screws. The integrated mounting rod is fixed to the
mast. CMA has an integrated lower glare screen to prevent
direct illumination of the domes by the sun at sunrise and sunset.
The mast shown intercepts a fraction D/2SS of the radiation that
is coming from the ground. In the most unfavourable situation
(sun at zenith) the pyranometer shadow decreases the signal by
a factor R2/H2.
Figure 4 Albedo configuration
2.2.6. Underwater use
The CMP/CMA radiometers are in principle watertight according to the IP 67 standard. However, the
hemispherical air cavity under the dome(s) acts as a negative lens. The parallel beam of direct solar
radiation becomes divergent after the passage of the outer dome. Consequently the intensity at the
sensor is lower than outside the dome(s). The calibrated sensitivity figure is not valid in this case and
must be derived empirically.
Page 9
CMP/CMA series manual
2.3. Electrical installation
As standard the CMP/CMA is supplied with a waterproof connector pre-wired to 10 m cable with a
number of leads and a shield covered with a black sleeve. The number of connector pins and cable
leads depends upon the model of radiometer and whether a temperature sensor is fitted (and which
type). The colour code of the wires and the connector pin numbers are shown on the instruction sheet.
Longer cables are available as options.
Preferably, secure the radiometer with its levelling screws or mounting rod to a metal support with a
good connection to earth (e.g. by using a lightning conductor).
The shield of the cable is connected to the aluminium radiometer housing through the connector body.
The shield at the cable end may be connected to ground at the readout equipment. Lightning can
induce high voltages in the shield but these will be led off at the pyranometer and data logger.
Kipp & Zonen pyranometer cables are of low noise type, but bending the cable produces small voltage
spikes, a tribo-electric and capacitance effect. Therefore, the cable must be firmly secured to minimise
spurious responses during stormy weather.
The impedance of the readout equipment loads the temperature compensation circuit and the
thermopile. It can increase the temperature dependency of the pyranometer. The sensitivity is affected
more than 0.1% when the load resistance is less than 100 k:. For this reason we recommend the use
of readout equipment with an input impedance of 1 M: or more. The solar integrators, data loggers
and chart recorders from Kipp & Zonen meet these requirements.
Long cables may be used, but the cable resistance must be smaller than 0.1% of the impedance of the
readout equipment. It is evident that the use of attenuator circuits to modify the calibration factor is not
recommended because the temperature response will also be affected.
A high input bias current at the readout equipment can produce several micro-Volts across the
impedance of the pyranometer and cable. The zero offset can be verified by replacing the pyranometer
impedance at the readout equipment input terminals with a resistor.
The pyranometer can also be connected to a computer or data acquisition system. A low voltage
analogue input must be available. The resolution of the Analogue-to-Digital Converter (ADC) must
allow a system sensitivity of about 1 bit per W/m2. More resolution is not necessary during outdoor
solar radiation measurements, because pyranometers exhibit offsets up to ± 2 W/m2 due to lack of
thermal equilibrium.
For amplification of the pyranometer signal Kipp & Zonen offers the AMPBOX signal amplifier. This
amplifier will convert the micro-Volt output from the pyranometer into a standard 4 – 20 mA signal. The
use of the AMPBOX amplifier is recommended for applications with long cables (> 100 m), electrically
noisy environments or data loggers with a current-loop input. The AMPBOX can be factory adjusted to
suit the sensitivity of an individual radiometer to produce a defined range, typically 4 – 20 mA
represents 0 – 1600 W/m2. The CMA series have two independent signal outputs, so two AMPBOX
amplifiers are required.
Page 10
CMP/CMA series manual
2.4. Operation
After completing the installation the radiometer will be ready for operation.
The irradiance value (EpSolar) can be simply calculated by dividing the output signal (Uemf) of the
pyranometer by its sensitivity (Sensitivity) as shown in Formula 1.
For calculation of the solar irradiance (global or reflected) the following formula must be applied:
E p Solar
EpSolar
Uemf
Sensitivity
U emf
S ensitivity
= Solar radiation
= Output of radiometer
= Sensitivity of radiometer
Formula 1
[W/m2]
[PV]
[PV/W/m2]
To be certain that the quality of the data is of a high standard, care must be taken with daily maintenance
of the radiometer. Once a voltage measurement is taken, nothing can be done to retrospectively improve
the quality of that measurement.
2.5. Measurement uncertainty
When a pyranometer is in operation, the performance of it is correlated to a number of parameters,
such as temperature, level of irradiance, angle of incidence, etc. Normally, the supplied sensitivity
figure is used to calculate the irradiances. If the conditions differ significantly from calibration
conditions, uncertainty in the calculated irradiances must be expected.
For a secondary standard instrument (the highest quality) the WMO expects maximum errors in the
hourly radiation totals of 3%. In the daily total an error of 2% is expected, because some response
variations cancel each other out if the integration period is long. Kipp & Zonen expects maximum
uncertainty of 2% for hourly totals and 1% for daily totals for the CMP 22 pyranometer. Many years of
experience has shown that pyranometer performance can be improved concerning zero offset type A by
using a well designed ventilation system. The Kipp & Zonen CV 2 ventilation unit is recommended to
minimise this small remaining error.
For the CMP 22 the effect of each parameter on the sensitivity can be shown separately.
The non-linearity error, the sensitivity variation with irradiance, is the same for any CMP 22 and is
shown in Figure 5 for a range from 0 to 1000 W/m2 referred to the calibration at 500 W/m2.
Figure 5 Non-linearity sensitivity variation of a CMP 22
Page 11
CMP/CMA series manual
The temperature dependence of the sensitivity is a function of the individual CMP 22. For a given
CMP 22 the response lies in the region between the curved lines in Figure 6. The temperature
dependence of each CMP 21 and CMP 22 pyranometer is characterised and supplied with the
instrument. Each CMP 21 and CMP 22 has a built-in temperature sensor to allow corrections to be
applied if required.
Figure 6 Typical temperature dependency of a CMP 22
The directional error is the summation of the azimuth and zenith error and is commonly given in %.
Figure 7 shows the maximum relative zenith error in any azimuth direction for the CMP 22. The
directional error of each CMP 21 and CMP 22 pyranometer is characterised and supplied with the
instrument.
Figure 7 Relative directional error of a CMP 22
Page 12
CMP/CMA series manual
2.6. Maintenance
Once installed the radiometer needs little maintenance. The outer dome(s) must be cleaned and
inspected regularly, ideally every morning. On clear windless nights the outer dome temperature of
horizontally placed radiometers will decrease, even to the dew point temperature of the air, due to
infrared radiation exchange with the cold sky. (The effective sky temperature can be 30qC lower than
the ground temperature). In this case dew, glazed frost or hoar frost can be precipitated on the top of
the outer dome and can stay there for several hours in the morning. An ice cap on the dome is a strong
diffuser and increases the pyranometer signal drastically, up to 50% in the first hours after sunrise.
Hoar frost disappears due to solar radiation during the morning, but should be wiped of as soon as
possible manually.
The dome of the pyranometer can be ventilated continuously by a heated blower to keep the dome
above dew point temperature. The need for heating strongly depends upon local climatological
circumstances. Generally, heating is advised during cold seasons when frost and dew can be expected.
The Kipp & Zonen CV 2 ventilation unit is specially designed for unattended operation under most
weather conditions and has a choice of heating levels.
Note that the CMA albedometers and the CMP 3 pyranometer cannot be used with the CV 2 ventilation
unit.
A periodic check is to ensure that the radiometer is level and that the silica gel desiccant is still
coloured orange. When the orange silica gel in the drying cartridge is turned completely transparent
(normally after several months), it must be replaced by fresh silica gel as supplied in the small refill
packs. The content of one pack is sufficient for one complete refill. At the same time check that the
radiometer mounting is secure and that the cable is in good condition.
Some tips when changing the dessicant:
-
Make sure the surfaces of the radiometer and the drying cartridge that touch the rubber o-ring are
clean (corrosion can do a lot of harm here and dirt, in combination with water, can cause this);
The rubber o-ring is coated with a silicon grease to improve the seal. If the rubber o-ring looks dry
apply some grease to it (Vaseline will also do);
Check that the drying cartridge is tightly threaded into the radiometer body.
It is very difficult to make the radiometers hermetically sealed; so, due to pressure differences between
the inside and the outside of the instrument, there will always be some exchange of (humid) air.
The radiometer sensitivity changes with time and with exposure to radiation. Calibration every two
years is advised. Further information about Kipp & Zonen recalibration services can be found in
Appendix VI.
Page 13
CMP/CMA series manual
3. Principle components of pyranometers
The detector of the Kipp & Zonen CMP/CMA series pyranometer is based on a passive thermal
sensing element called a thermopile. Although the detector construction differs from model to model,
the fundamental working principle is applicable to all CMP/CMA series radiometers.
The thermopile responds to the total power absorbed by the black surface coating, which is a nonspectrally selective paint, and warm up. The heat generated flows through a thermal resistance to the
heat-sink (the pyranometer body). The temperature difference across the thermal resistance of the
detector is converted into a voltage as a linear function of the absorbed solar irradiance.
The rise of temperature is easily affected by wind, rain and thermal radiation losses to the environment
('cold' sky). Therefore the detector is shielded by two domes (the entry-level CMP 3 has only one dome
to reduce size and cost). These domes allow equal transmittance of the direct solar component for
every position of the sun on the celestial sphere. A drying cartridge (dessicator) in the radiometer
housing is filled with silica gel and prevents dew on the inner sides of the domes, which can cool down
considerably on clear windless nights.
Figure 8 Construction details of a pyranometer
3.1. Dome
The dome material of the radiometer defines the spectral measurement range of the instrument. In
general about 97 – 98% of the solar radiation spectrum will be transmitted through the domes and will
be absorbed by the detector. The solar irradiance can come from any direction within the hemisphere
above the radiometer and therefore the domes are designed to minimize errors in measurement at all
incident angles.
CMP/CMA series radiometers, except the CMP/CM 3, have two high optical grade hemispherical
domes, one inner dome and one outer dome. In the chapter ‘pyranometer physical properties’ the
physical relation between dome and pyranometer performance will be explained.
For each particular model the specific dome material and spectral range is shown in the chapter
containing the instrument specifications.
Page 14
CMP/CMA series manual
3.2. Detector
The thermopile sensing element is made up of a large number of thermocouple junction pairs
connected electrically in series. The absorption of thermal radiation by one of the thermocouple
junctions, called the active (or ‘hot’) junction, increases its temperature. The differential temperature
between the active junction and a reference (‘cold’) junction kept at a fixed temperature produces an
electromotive force directly proportional to the differential temperature created. This is a thermoelectric
effect. The sensitivity of a pyranometer depends on the individual physical properties of the thermopile
and construction. The sensitivity of each thermopile is unique and therefore each radiometer has
unique calibration factor, even with the same radiometer model.
On the top surface of the sensor a black paint is deposited which has a very rough structure containing
many micro-cavities that effectively ‘’trap’’ more than 97% of the incident radiation in a broad spectral
range. Furthermore, the spectral selectivity is less than 2%. This means that within the spectral range
of the pyranometer, the absorption for each wavelength is equal to within 2%. The black painted
sensing element forms the detector. Considering the long-term stability of the instrument, the black
paint is one of the most crucial and delicate parts of the pyranometer. Kipp & Zonen black paint gives
the best possible stability over a long period of time under all meteorological circumstances.
3.3. Housing
The radiometer housing accommodates all fundamental pyranometer parts. The anodized Aluminium
parts are light weight and give a high mechanical and thermal stability to the instrument. Due to its fine
mechanical construction all pyranometers are virtually sealed and comply to the international standard
IP 67. Each pyranometer model can be leveled by using the bubble level and two leveling feet. For
ease of maintenance the bubble level is situated next to the dome of the instrument and due to the
special shape of the sun shield it is visible from above. The sun shield acts to protects all the external
parts from radiation and to reduce solar heating of the housing.
3.4. Drying cartridge
In case moisture enters the radiometer body the silica-gel desiccant regulates the humidity level inside
the pyranometer. Initially the desiccant will have an orange color. After some time it becomes saturated
with moisture and the colour will change to become clear (transparent). At this time the contents of the
drying cartridge should be replaced with fresh, unsaturated orange colored desiccant as soon as
possible. Replacement desiccant is available through Kipp & Zonen distributors.
3.5. Cable and connector
For ease of installation and replacement during recalibration of the radiometer, the CMP/CMA series
are provided with a weather proof signal cable connector.
Kipp & Zonen radiometers use a custom-made cable that is selected as a low noise type particularly
suited to handle the low voltage output of the thermopile or of a temperature sensor.
The shield of the cable is connected to the metal body of the connector and preferably should be
connected to ground at the readout equipment. Cables come pre-wired to the connector plug in a
range of lengths.
Page 15
CMP/CMA series manual
4. Pyranometer physical properties
4.1. Spectral range
The spectrum of the solar radiation reaching the Earth’s surface is in the wavelength range between
280 nm and 4000 nm, extending from ultraviolet (UV) to the far infrared (FIR) as shown in Figure 9.
Due to the excellent physical properties of the glass dome and black absorber paint, Kipp & Zonen
CMP/CMA series radiometers are equally sensitive in a wide spectral range. 97-98% of the total
energy will be absorbed by the thermal detector. The CMP 22 pyranometer has a wider spectral range
due to the quartz domes used in its construction.
Figure 9 Solar irradiance spectrum at the Earth’s surface and pyranometer response
4.2. Sensitivity
The radiometer thermopile sensitivity is mainly determined by the physical properties of the detector
itself. The thermoelectric power, thermal conductivity of the junctions and the overall dimensions of the
sensing element are related to its sensitivity.
4.3. Impedance
The radiometer impedance is defined as the total electrical impedance at the radiometer output
connector fitted to the housing. It arises from the electrical resistance in the thermal junctions, wires
and passive electronics within the radiometer.
4.4. Response time
Any measuring device requires a certain time to react to a change in the parameter being measured.
The radiometer requires time to respond to change in the incident radiation. The response time is
normally quoted as the time for the output to reach 95% (sometimes 63%) of the final value following a
step-change in irradiance. It is determined by the physical properties of the thermopile and the
radiometer construction. CMP/CMA series radiometers have a fast response, which makes them
suitable for measuring solar radiation under variable weather conditions.
Page 16
CMP/CMA series manual
4.5. Non-linearity
The non-linearity of a radiometer is the percentage deviation in the sensitivity over an irradiance range
from 0 to 1000 W.m-2 compared to the sensitivity calibration irradiance of 500 W.m-2. The non-linearity
effect is due to convective and radiative heat losses at the black absorber surface which make the
conditional thermal equilibrium of the radiometer non-linear.
4.6. Temperature dependence
The sensitivity change of the radiometer with ambient temperature change is related to the thermodynamics of the radiometer construction. The temperature dependence is given as percent deviation
with respect to the calibrated sensitivity at +20qC. Some of the CMP/CMA series radiometer models
have passive electrical compensation circuits to minimise this effect. Each CMP 21 and CMP 22
pyranometer is supplied with an individual test certificate stating the temperature dependency in the
range from -20qC to +50qC, at 10qC intervals. The CMP 21 and CMP 22 are fitted as standard with an
internal temperature sensor to allow sensitivity corrections to be applied if desired.
4.7. Tilt error
This is the deviation from the sensitivity at 0q tilt (exactly horizontal) over the range from 0q to 90q tilt
under 1000 W.m-2 normal incidence irradiance. The tilt response is proportional to the incident
radiation. The error could be corrected for, in applications where it is necessary to install the
pyranometer on an inclined surface, but is usually insignificant.
4.8. Zero offset A
By physical laws any object having a certain temperature will exchange radiation with its surroundings.
The domes of upward facing radiometers will exchange radiation primarily with the relatively cold
atmosphere. In general, the atmosphere will be cooler than the ambient temperature at the Earth’s
surface. For example, a clear sky can have an effective temperature up to 50qC cooler, whereas an
overcast sky will have roughly the same temperature as the Earth’s surface. Due to this the
pyranometer domes will ‘lose’ energy to the colder atmosphere by means of radiative transfer. This
causes the dome to become cooler than the rest of the instrument. This temperature difference
between the detector and the instrument housing will generate a small negative output signal which is
commonly called Zero Offset type A. This effect is minimized by using an inner dome. This inner dome
acts as a ‘radiation buffer’. The above is illustrated in Figure 10.
This effect can be minimized by applying appropriate
ventilation of the instrument. The CV 2 ventilation unit is
specially designed for the CMP series, except CMP 3.
Figure 10 Zero Offset type A
Page 17
CMP/CMA series manual
4.9. Zero offset B
Proportionally to the ambient temperature the instrument temperature varies and causes heat currents
inside the instrument. This will cause an offset commonly called Zero Offset type B. It is quantified as
the response in W/m2 to a 5 K/hr change in ambient temperature.
4.10.
Operating temperature
The operating temperature range of the radiometer is determined by the physical properties of the
individual parts. Within the specified temperature range Kipp & Zonen radiometers can be operated
safely. Outside this temperature range special precautions should be taken to prevent any physical
damage or performance loss of the radiometer. Please contact your distributor for further information
regarding operation in unusually harsh temperature conditions.
4.11.
Field of view
The field of view is defined as the unobstructed open viewing angle of the radiometer. ISO and WMO
require that a pyranometer for the measurement of global solar radiation has a field of view of 180q in
all directions (i.e. a hemisphere). The inherent field of view of the instrument should not be confused
with the clear field of view of the installation location.
4.12.
Directional response
Radiation incident on a flat horizontal surface originating
from a point source with a defined zenith position will have
an intensity value proportional to the cosine of the zenith
angle of incidence. This is sometimes called the ‘cosinelaw’ or ‘cosine-response’ and is illustrated in figure 11.
Ideally a pyranometer has a directional response which is
exactly the same as the cosine-law. However, in a
pyranometer the directional response is influenced by the
quality, dimensions and construction of the domes. The
maximum deviation from the ideal cosine-response of the
pyranometer is given up to 80q angle of incidence with
respect to 1000 W/m2 irradiance at normal incidence (0q).
Figure 11 Solar zenith angle
4.13.
Maximum irradiance
The maximum irradiance is defined as the total irradiance level beyond which physical damage may
occur to the instrument.
Page 18
CMP/CMA series manual
4.14.
Non-stability
This is the percentage change in sensitivity over a period of one year. This effect is mostly due to
degradation by UV radiation of the black absorber paint on the sensing element surface. Kipp & Zonen
recommends recalibration every two years. However, for quality assurance purposes some institutes,
companies or networks may require more or less frequent recalibration. Please read the chapter on the
calibration procedure for pyranometers for more information.
4.15.
Spectral selectivity
Spectral selectivity is the variation of the dome transmittance and absorption coefficient of the black
detector paint with wavelength and is commonly specified as % of the mean value.
4.16.
Environmental
The CMP/CMA series are intended for outdoor use under all expected weather conditions. The
radiometers comply with IP 67 and their solid mechanical construction is suitable to be used under all
environmental conditions within the specified ranges.
4.17.
Uncertainty
The measurement uncertainty can be described as the maximum expected hourly or daily uncertainty
with respect to the ‘absolute truth’. The confidence level is 95%, which means that 95% of the datapoints lie within the given uncertainty interval representing the absolute value. Kipp & Zonen
empirically determine uncertainty figures based on many years of field measurements.
Page 19
CMP/CMA series manual
5. Calibration
5.1. Calibration principle
An ideal radiometer gives voltage output that is proportional to the absolute irradiance level. This
relationship can be expressed as a constant ratio called ‘sensitivity’ (Sensitivity).
The sensitivity figure of a particular radiometer is unique. It is determined in the manufacturer's
laboratory by comparison against a reference radiometer of similar type. The reference radiometer is
calibrated outdoors regularly at the World Radiation Centre (WRC) at Davos, Switzerland. The spectral
content of the laboratory calibration lamp differs from the outdoor solar spectrum at the World
Radiation Centre. However, this has no consequences for the transfer of calibration, because standard
and test radiometers have the same black coating and domes.
The supplied sensitivity figure is valid for the following conditions:
An ambient temperature of +20°C.
For a horizontal radiometer and for a tilted radiometer.
Normal incident radiation of 500 W/m2.
For any other condition the sensitivity figure can be used within uncertainty bands given in the
specifications for each model.
A summary of calibration methods is also found in the WMO guide of 1996.
5.2. Calibration procedure at Kipp & Zonen
5.2.1. The calibration facility
The indoor calibration procedure, according to ISO 9847 Appendix III, is based on a side-by-side
comparison with a reference radiometer under a stable artificial sun. Kipp & Zonen uses a 150 W
Metal-Halide high-pressure gas discharge lamp with voltage stabilisation. Behind the lamp is a reflector
with a diameter of 16.2 cm. The reflector is 110 cm above the radiometers producing a vertical beam.
The irradiance at the radiometers is approximately 500 W/m².
To minimise stray light from the walls and the operator, the light is restricted to a small cone around the
two radiometers. The unknown radiometer 'a' and the reference radiometer 'b' are placed side by side
on a small table. The table can rotate to interchange the positions (1 and 2) of the radiometers. The
lamp is centred on the rotating axis of this table. Actually there is no normal incidence of the radiation,
but the angle of incidence is the same for both radiometers (3°) so this cannot give rise to errors. The
two radiometers are not levelled with the screws, but placed on their bases. The effect of the small
beam tilt is negligible (compare cos. 3° = 0.9986 and cos. 4° = 0.9976).
5.2.2. Calibration procedure
After illuminating for 30 seconds, the output voltages of both radiometers are integrated over 30
seconds. Next, both radiometers are covered. After 30 seconds the zero offset signals of both
radiometers are integrated, again over a period of 30 seconds. The irradiance at position 1 (radiometer
'a') may be slightly different from that at position 2 (radiometer 'b') due to asymmetry in the lamp optics,
etc. Therefore the radiometers are interchanged by rotating the table and the whole procedure is
repeated.
Page 20
CMP/CMA series manual
5.2.3. Calculation
The sensitivity of the unknown pyranometer is calculated with formula 2:
S
Sb
A
A’
B
B’
Sa
a
A A'
B B ' sb
Formula 2
= Sensitivity of the reference radiometer at +20 qC.
= Output of test radiometer at position 1
= Output of test radiometer at position 2
= Output of reference radiometer at position 2
= Output of reference radiometer at position 1
= Sensitivity of the test radiometer at +20 qC.
Output = mean value at 100% response minus zero offset signal
5.2.4. Zero offset
The lamp housing and beam restrictors heat up and emit long-wave infrared radiation, which heats up
the outer glass dome and, indirectly, the inner one. When the radiometers are shaded, there still
remains a small signal of up to +20 µV due to long-wave infrared radiation from the inner dome to the
sensor. This zero offset is decreasing with a time constant (1/e) of several minutes.
A zero offset is also embodied in the response due to illumination. To correct for this unwanted
response, the zero offset read after 60 seconds of shading is subtracted.
5.3. Traceability to World Radiometric Reference
Reference radiometers, which are calibrated annually by the World Radiation Centre in Davos, are
used for the calibration of radiometers manufactured by Kipp & Zonen. The reference radiometers are
fully characterized, i.e. linearity, temperature dependence and directional response are recorded.
Kipp & Zonen keeps two reference radiometers for each radiometer model. These reference
radiometers are sent alternate years to WRC for calibration, so production and calibration in Delft can
carry on without interruption.
5.4. Recalibration
Radiometer sensitivity changes with time and with exposure to radiation. Periodic calibration every two
years is advised.
Accurate calibrations can be done outdoors under clear conditions by comparison with a reference
pyrheliometer. Many national or regional weather services have calibration facilities. Their standard
pyrheliometer is compared with the World Radiometric Reference at Davos, Switzerland. This
embodies several absolute cavity (black body) pyrheliometers. Information about regional calibration
centres can be found in appendix V.
Page 21
CMP/CMA series manual
There are several procedures for transferring calibration from a narrow field of view instrument
(pyrheliometer) to a wide field of view instrument (pyranometer). For example the direct component of
the solar radiation is eliminated temporarily from the pyranometer by shading the whole outer dome of
the instrument with a disk. There is however no thermal equilibrium with this method and some
pyranometer models show zero-offset drift.
There is another procedure, during which the unknown pyranometer remains in its normal operating
condition. This 'component' method involves measuring the direct component with a pyrheliometer and
the diffuse component with a disk shaded pyranometer. As, during a clear day, the diffuse radiation is
only about 10% of the global radiation, the sensitivity of the second pyranometer does not need to be
known very accurately. Both procedures are suitable to obtain a working standard pyranometer. The
latter is extensively described in international standard ISO 9846.
Transfer from the working standard pyranometer to other pyranometers can be done in sunlight. The
pyranometers must be mounted side by side so that each views the same sky dome. It is desirable to
integrate, or average, the outputs over a period of time and then compute the calibration constants on
the basis of these averages. This reduces the errors due to changing parameters during the day.
Transfer from another pyranometer in the laboratory is only possible when both pyranometers are of
the same type and have the same glass domes and optical coatings. Kipp & Zonen can recalibrate
pyranometers according to this method.
Page 22
CMP/CMA series manual
6. CMP/CMA models
The CMP series offers 5 different models in the range from CMP 3 up to CMP 22. The mechanical
construction of the CMP 3 differs from the others in that it has a single dome, smaller housing
dimensions and no drying cartridge (the housing is completely sealed). Features and specification of
the double dome pyranometers in the range from CMP 6 to CMP 22 are specified in this chapter. The
CMP/CMA series is designed for measuring the irradiance (radiant-flux, W/m2) on a plane surface,
which results from the direct solar irradiance and from the diffuse radiation incident from the
hemisphere above.
A CMP/CMA radiometer includes an integrated bubble level, refillable drying cartridge, white snap-on
sun shield, and a shielded signal output cable with connector. In addition, the CMA series
albedometers also have an integrated conical lower glare shield to prevent illumination of the lower
glass dome at sunrise and sunset. The albedometers are equipped with a mounting rod for attachment
to a mast. All albedometers are supplied with a calibration certificate indicating both the upper and
lower sensor sensitivities.
The CMP series (except CMP 3) can be used in conjunction with the Kipp & Zonen CV 2 ventilation
unit for enhanced measurement performance and overall reduced instrument maintenance.
For measuring the diffuse component of solar radiation only, the direct solar component can be
shielded statically from the CMP pyranometers by the Kipp & Zonen shadow ring CM 121, and fully
automatically by the 2 AP sun tracker with shading system.
6.1. CMP 6 / CMA 6
Fully compliant with all ISO-9060 specification criteria for an ISO First Class pyranometer, the
CMP/CMA 6 features a sixty-four junction (connected in series) thermocouple sensing element. The
sensing element is coated with a highly stable carbon based inorganic coating, which delivers excellent
spectral absorption and long-term stability characteristics. The detector is housed under two concentric
glass domes which are 2 mm thick.
The albedo version is constructed around two CMP 6 pyranometer sensors and also complies with the
ISO classification. Both sensors are contained in a single housing and have individual sensitivities.
6.2. CMP 11 / CMA 11
Fully compliant with all ISO-9060 specification criteria for an ISO Secondary Standard pyranometer,
the CMP 11 features a 32 junction (connected in series) thermocouple sensing element which has
faster response than the CMP 6 / CMA 6. Passive temperature compensation is included for improved
temperature dependence of sensitivity and non-linearity is reduced. The sensing element is housed
under two higher quality concentric glass domes which are 2 mm thick and provide improved
directional error. The radiometric leveling is more accurate than in CMP 6 / CMA 6.
CMA 11 is constructed around two CMP 11 pyranometer sensors. Both sensors are contained in a
single housing and have individual sensitivities.
Page 23
CMP/CMA series manual
6.3. CMP 21
CMP 21 is a high precision scientific pyranometer based upon the CMP 11 but with individual
optimisation and characterisation and an integrated housing temperature sensor. CMP exceeds the
ISO-9060 specification criteria for an ISO Secondary Standard pyranometer
The special features of the CMP 21 are:
x
x
x
Individually optimised and characterised temperature dependence.
Individually characterised directional response.
Integrated housing temperature sensor.
6.4. CMP 22
CMP 22 is a high precision scientific pyranometer base upon the CMP 21 but with strictly selected
quartz domes which are 4 mm thick. CMP 22 has an extended spectral range to match pyrheliometers
with quartz windows. Because of the high optical quality and higher refractive index of the quartz
domes the directional error is reduced to less than 5 W/m2.
The zero offset behaviour is fundamentally improved in two ways:
The zero offset caused by changing instrument temperature is negligible, because of the very well
balanced thermopile construction.
The zero offset due to the difference between sensor and dome temperature (e.g. Far Infrared
Radiation absorption or emission by the outer dome) is minimised using an improved thermal coupling
of sensor and top of dome. Thicker domes, both of 4mm, and the 50% higher thermal conductivity of
quartz, compared to glass, improve this thermal coupling.
CMP 22 features are:
x Negligible thermal gradient zero-offset.
x Lowest zero-offset due to FIR radiation.
x Broadened spectral range 200 – 3600 nm.
x Directional error < 5 W/m2.
x Lowest temperature dependency of sensitivity.
Like the CMP 11 and CMP 21 pyranometers, the CMP 22 complies with the specifications for the best
of three classes of pyranometer, ‘High quality’, as defined in the 'Guide to meteorological Instruments
and Methods of Observation', sixth edition, 1996, of the World Meteorological Organisation (*WMO)
Geneva, Switzerland. Most specifications of the CMP 22 are twice as good as required.
* The WMO classification is adapted from the international standard ISO 9060 (1990). Herein ‘high
quality’ class is referred to as ‘secondary standard’.
Page 24
CMP/CMA series manual
6.5. CMP / CMA series performance specifications
Specification
Unit
CMP 6/ CMA 6
CMP 11 / CMA 11
CMP 21
CMP 22
Spectral range
Sensitivity
Impedance
nm
µV/W/m²
:
285 - 2800
7 to 14
10 to 100
<5
< 1.7
< 0.2
285 - 2800
7 to 14
10 to 100
<5
< 1.7
< 0.2
200 - 3600
7 to 14
10 to 100
<5
< 1.7
< 0.2
Response time
s
Non-linearity
%
285 - 2800
5 to 20
20 to 200
< 18
< 6
<1
Temperature dependence of
sensitivity
%
<4
<1
< 1*
< 0.5*
%
W/m²
W/m²
qC
<1
< 15
<4
-40 to +80
180º
< 20
2000
<1
0 - 100
<5
< 0.2
<7
<2
-40 to +80
180º
< 10
4000
< 0.5
0 - 100
<2
< 0.2
<7
<2
-40 to +80
180º
< 10
4000
< 0.5
0 - 100
<2
< 0.2
<3
<1
-40 to +80
180º
<5
4000
< 0.5
0 - 100
<1
Tilt error
Zero offset A
Zero offset B
Operating temperature
Field of view
Directional error
Maximum irradiance
Non-stability
Humidity
Uncertainty in daily total
2
W/m
2
W/m
%
% RH
%
Definition
50 % response point
Signal output for 1 W/m² irradiance
At instrument housing connector
95% of final value
63 % of final value
From 0 to 1000 W/m² irradiance
Variation in range - 10 °C to + 40 °C
from value at + 20 °C
*(- 20 °C to + 50 °C)
Deviation when facing downwards
At 0 to - 200 W/m² of IR net radiation
At 5 K/h temperature change rate
Storage temperature is the same
Hemispherical
At 80° with 1000 W/m² irradiance
Level above which damage may occur
Variation in sensitivity per year
Relative Humidity
95 % confidence level
Page 25
CMP/CMA series manual
6.6. CMP / CMA series general specifications
Page 26
CMP/CMA series manual
7. Frequently asked questions
The most frequently asked questions are listed below. For an update refer to the Kipp & Zonen website
at www.kippzonen.com
Negative output during night-time measurements?
This error is related to Zero Offset type A. Normally this zero offset is present when the inner dome has
a different temperature from the cold junctions of the sensor. Practically this is always the case when
there is a clear sky. Because of the low effective sky temperature (< 0°C) the Earth’s surface emits
roughly 100 W/m2 of long-wave infrared radiation upwards. The outer glass dome of a pyranometer
also has this emission and is cooling down several degrees below air temperature (the emissivity of
glass for the particular wavelength region is nearly 1).
The emitted heat is attracted from the body (by conduction in the dome), from the air (by wind) and
from the inner dome (through infrared radiation). The inner dome is cooling down too and will attract
heat from the body by conduction and from the sensor by the net infrared radiation. The latter heat flow
is opposite to the heat flow from absorbed solar radiation and causes the well-known zero depression
at night. This negative zero offset is also present on a clear day but is hidden in the solar radiation
signal.
Zero Offset type A can be checked by placing a light and IR reflecting cap over the pyranometer. The
response to solar radiation will decay with a time constant (1/e) of 1 second, but the dome temperature
will go to equilibrium with a time constant of several minutes. So after half a minute the remaining
signal represents mainly Zero Offset type A.
Good ventilation of domes and body is the solution to minimising zero offsets. Kipp & Zonen advises
the CV 2 ventilation unit for optimal ventilation and suppression of zero offset type A. Using the CV 2
zero offset type A will decrease by ~ 50%.
Maximum and minimum irradiation quantities?
Due to possible reflection from clouds the global irradiance at sea level can rise above the extraterrestrial direct irradiance of 1367 W/m2 at the top of the atmosphere. Values up to 1500 W/m2 have
been reported.
Because the clouds move, this irradiance value mostly appears as short events of a few minutes
duration.
What is the primary entry point for humidity?
The drying cartridge seal and the silicon glue of the domes are not fully airtight.
Is the pyranometer sensitivity affected by the length of the signal cable?
With longer cable lengths the impedance increases, however it does not affect the radiometer
sensitivity for the following reason. The impedance of the voltage measurement device is at least
10000 times more than the impedance of the pyranometer plus cable. Therefore the current that goes
through the readout cable is negligible and won’t generate an offset. However, the loading may affect
the temperature compensation circuit to some extent.
Page 27
CMP/CMA series manual
8. Trouble shooting
The following contains a procedure for checking the instrument in case it appears that it does not
function as it should.
Trouble shooting:
Output signal fails or shows improbable results:
Check the wires are properly connected to the readout equipment.
Check the instrument location. Are there any obstructions that cast a shadow on the instrument
by blocking the direct sun during some part of the day?
Check the dome, it should be clear and clean. If water is deposited on the inside, please change
the desiccant. If too much water is deposited internally the drying cartridge should be removed
and the instrument warmed to dry it.
Check instrument impedance (see specifications for expected values).
Check data logger or integrator offset by connecting a dummy load (100 Ohm resistor). This
should give a “zero” reading.
Check levelling (bubble inside ring)
If water or ice is deposited on the dome, clean it. Probably water droplets will evaporate in less than
one hour under sunlight.
Any visible damage or malfunction should be reported to your distributor, who will suggest appropriate
action.
Page 28
CMP/CMA series manual
Appendix I Radiometric terminology
Term
Explanation
Albedo
The portion of incoming radiation which is reflected by a surface
Azimuth angle
Angle in horizontal direction (0-360q)
Angle of incidence
Incident angle from zenith (vertical)
Cosine response
Detector response according to the cosine law
Diffuse solar irradiance
Solar radiation, scattered by water vapor, dust and other particles as
it passes through the atmosphere
Direct solar irradiance
Radiation that has travelled a straight path from the sun
Global solar irradiance
Total irradiance falling on a horizontal surface (Diffuse + Direct cos D)
Irradiance
Radiant flux density (W/m2)
Long-wave radiation
Radiation with wavelengths > 4 µm and < 100 µm
Pyranometer
Radiometer suitable to measure short-wave global radiation
Pyrgeometer
Radiometer suitable to measure downward long-wave radiation
Pyrheliometer
Radiometer suitable to measure direct irradiance
Short-wave radiation
Radiation with wavelengths > 280 nm and < 4 µm
Thermopile
Thermal detector mad up of many thermocouple junctions
WMO
World Meteorological Organisation
WRC
World Radiation Center (in Davos, Switzerland)
WRR
World Radiation Reference (standard radiation scale)
WSG
World Standard Group (radiometer standards maintained in Davos)
Zenith angle
Angle from zenith (0q, vertical)
Page 29
CMP/CMA series manual
Appendix II 10k thermistor specifications
YSI Thermistor 44031 - Resistance versus Temperature in °C
YSI 44031 Temperature vs. Resistance
Temperature Resistance Temperature Resistance Temperature Resistance
[ °C ]
-30
-29
-28
-27
-26
-25
-24
-23
-22
-21
-20
-19
-18
-17
-16
-15
-14
-13
-12
-11
-10
-9
-8
-7
-6
-5
-4
-3
-2
-1
[ °F ]
[ Ohm ]
-22.0
135,200
-20.2
-18.4
-16.6
-14.8
-13.0
-11.2
-9.4
-7.6
-5.8
-4.0
-2.2
-0.4
1.4
3.2
5.0
6.8
8.6
10.4
12.2
127,900
121,100
14.0
15.8
17.6
19.4
21.2
23.0
24.8
26.6
28.4
30.2
114,600
108,600
102,900
97,490
92,430
87,660
83,160
78,910
74,910
71,130
67,570
64,200
61,020
58,010
55,170
52,480
49,940
47,540
45,270
43,110
41,070
39,140
37,310
35,570
33,930
32,370
30,890
[ °C ]
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
[ °F ]
32.0
33.8
35.6
37.4
39.2
41.0
42.8
44.6
46.4
48.2
50.0
51.8
53.6
55.4
57.2
59.0
60.8
62.6
64.4
66.2
68.0
69.8
71.6
73.4
75.2
77.0
78.8
80.6
82.4
84.2
[ Ohm ]
29,490
28,150
26,890
25,690
24,550
23,460
22,430
21,450
20,520
19,630
18,790
17,980
17,220
16,490
15,790
15,130
14,500
13,900
13,330
12,790
12,260
11,770
11,290
10,840
10,410
10,000
9,605
9,227
8,867
8,523
[ °C ]
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
[ °F ]
86.0
87.8
89.6
91.4
93.2
95.0
96.8
98.6
100.4
102.2
104.0
105.8
107.6
109.4
111.2
113.0
114.8
116.6
118.4
120.2
122.0
123.8
125.6
127.4
129.2
131.0
132.8
134.6
136.4
138.2
[ Ohm ]
8,194
7,880
7,579
7,291
7,016
6,752
6,500
6,258
6,026
5,805
5,592
5,389
5,193
5,006
4,827
4,655
4,489
4,331
4,179
4,033
3,893
3,758
3,629
3,504
3,385
3,270
3,160
3,054
2,952
2,854
Page 30
CMP/CMA series manual
Appendix III Pt-100 specifications
Pt-100 - Resistance versus Temperature in ºC and ºF
Pt-100 Temperature vs. Resistance
Temperature Resistance Temperature Resistance Temperature Resistance
[ °C ]
-30
-29
-28
-27
-26
-25
-24
-23
-22
-21
-20
-19
-18
-17
-16
-15
-14
-13
-12
-11
-10
-9
-8
-7
-6
-5
-4
-3
-2
-1
[ °F ]
-22.0
-20.2
-18.4
-16.6
-14.8
-13.0
-11.2
-9.4
-7.6
-5.8
-4.0
-2.2
-0.4
1.4
3.2
5.0
6.8
8.6
10.4
12.2
14.0
15.8
17.6
19.4
21.2
23.0
24.8
26.6
28.4
30.2
[ Ohm ]
88.2
88.6
89.0
89.4
89.8
90.2
90.6
91.0
91.4
91.8
92.2
92.6
93.0
93.3
93.7
94.1
94.5
94.9
95.3
95.7
96.1
96.5
96.9
97.3
97.7
98.0
98.4
98.8
99.2
99.6
[ °C ]
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
[ °F ]
32.0
33.8
35.6
37.4
39.2
41.0
42.8
44.6
46.4
48.2
50.0
51.8
53.6
55.4
57.2
59.0
60.8
62.6
64.4
66.2
68.0
69.8
71.6
73.4
75.2
77.0
78.8
80.6
82.4
84.2
[ Ohm ]
100.0
100.4
100.8
101.2
101.6
102.0
102.3
102.7
103.1
103.5
103.9
104.3
104.7
105.1
105.5
105.9
106.2
106.6
107.0
107.4
107.8
108.2
108.6
109.0
109.4
109.7
110.1
110.5
110.9
111.3
[ °C ]
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
[ °F ]
86.0
87.8
89.6
91.4
93.2
95.0
96.8
98.6
100.4
102.2
104.0
105.8
107.6
109.4
111.2
113.0
114.8
116.6
118.4
120.2
122.0
123.8
125.6
127.4
129.2
131.0
132.8
134.6
136.4
138.2
[ Ohm ]
111.7
112.1
112.5
112.8
113.2
113.6
114.0
114.4
114.8
115.2
115.5
115.9
116.3
116.7
117.1
117.5
117.9
118.2
118.6
119.0
119.4
119.8
120.2
120.6
120.9
121.3
121.7
122.1
122.5
122.9
Page 31
CMP/CMA series manual
Appendix IV classification According to WMO Guide 1996
Characteristics
ISO 9060 classification
Response time (95 percent
response)
CMP 22
CMP 21
CMP 11
CMA 11
CMP 6
CMA 6
High
quality
Good
quality
Moderate
quality
Secondary
standard
Secondary
standard
Secondary
standard
First class
Secondary
standard
First class
Second
class
5s
5s
5s
18 s
< 15 s
< 30 s
< 60 s
r 3 W/m2
r 7 W/m2
r 7 W/m2
r 15 W/m2
r 7 W/m2
r 15 W/m2
r 30 W/m2
r 1 W/m2
r 2 W/m2
r 2 W/m2
r 4 W/m2
r 2 W/m2
r 4 W/m2
r 8 W/m2
r 1 W/m2
r 1 W/m2
r 1 W/m2
r 1 W/m2
r 1 W/m2
r 5 W/m2
r 10 W/m2
< 0.5
< 0.5
< 0.5
<1
r 0.8
r 1.5
r 3.0
r 5 W/m2
r 10 W/m2
r 10 W/m2
r 20 W/m2
r 10 W/m2
r 20 W/m2
r 30 W/m2
r2
r4
r8
r 0.5
r1
r3
r2
r5
r 10
Zero offset:
(a) Response to 200 W/m2
net thermal radiation
(ventilated)
(b) Response 5 K/h change
in ambient temperature
Resolution (smallest detectable
change)
Stability (change per year,
percentage of full scale)
Directional response of beam
radiation
(The range of errors caused by
assuming that the normal incidence
responsivity is valid for all directions
when measuring, from any direction,
a beam radiation whose normal
incidence irradiance is 1000 W/m2)
Temperature response (percentage
of maximum due to any change of
ambient temperature within an
interval of 50 K)
Non-linearity (percentage deviation
from the responsivity at 500 W/m2
due to any change of irradiance
within the range 100 to 1000 W/m2)
r 0.5
r1
r1
r4
-200C-+500C
-200C-+500C
-100C-+400C
-100C-+400C
r 0.2
r 0.2
r 0.2
r1
Spectral sensitivity (percentage of
deviation of the product of spectral
absorptance and spectral
transmittance from the corresponding
mean within the range of 0.3 to 3 Pm)
Tilt response (percentage deviation
from the responsivity at 0q tilt,
horizontal, due to change in tilt from
0q to 90q at 1000 W/m2 irradiance)
Achievable uncertainty, 95 percent
confidence level
Hourly totals
Daily totals
r 0.2
r 0.2
r 0.2
r1
r 0.5
r2
r5
1%
2%
2%
5%
3%
2%
8%
5%
20%
10%
Page 32
CMP/CMA series manual
Appendix V List of World and Regional Radiation Centres
World Radiation Centres
Davos (Switzerland)
St. Petersburg (Russia) (data centre only)
Region I (Africa)
- Cairo (Egypt)
- Khartoum (Sudan)
- Kinshasa (Dem. Rep. of the Congo)
- Lagos (Nigeria)
- Tamanrasset (Algeria)
- Tunis (Tunisia)
Region II (Asia)
- Pune (India)
- Tokyo (Japan)
Region III (South America)
- Buenos Aires (Argentina)
- Lima (Peru)
- Santiago (Chile)
Region IV (North and Central America)
- Toronto (Canada)
- Boulder (United States)
- Mexico City (Mexico)
Region V (South-West Pacific)
- Melbourne (Australia)
Region VI (Europe)
- Budapest (Hungary)
- Davos (Switzerland)
- St. Petersburg (Russian Federation)
- Norrköping (Sweden)
- Trappes/Carpentras (France)
- Uccle (Belgium)
- Lindenberg (Germany)
Page 33
CMP/CMA series manual
Appendix VI Recalibration service
Pyranometers, Albedometers, Pyrgeometers, UV-Radiometers &
Sunshine Duration Sensors
Kipp & Zonen solar radiation measurement instruments comply with the most demanding international
standards. In order to maintain the specified performance of these instruments, Kipp & Zonen
recommends calibration of their instruments every two years.
This can be done at the Kipp & Zonen factory. Here, recalibration to the highest standards can be
performed at low cost. Recalibration can usually be performed within four weeks. If required, urgent
recalibration can be accomplished in three weeks or less (subject to scheduling restrictions). Kipp &
Zonen will confirm the duration of recalibration at all times. Please note that special quantity
recalibration discounts are available for instruments of the same type.
Page 34
Our customer support remains at your disposal for any maintenance or repair, calibration,
supplies and spares.
Für Servicearbeiten und Kalibrierung, Verbrauchsmaterial und Ersatzteile steht Ihnen unsere
Customer Support Abteilung zur Verfügung.
Notre service 'Support Clientèle' reste à votre entière disposition pour tout problème de
maintenance, réparation ou d'étalonnage ainsi que pour les accessoires et pièces de rechange.
Nuestro apoyo del cliente se queda a su disposición para cualquier mantenimiento o la
reparación, la calibración, los suministros y reserva.
HEAD OFFICE
Kipp & Zonen B.V.
Delftechpark 36, 2628 XH Delft
P.O. Box 507, 2600 AM Delft
The Netherlands
T: +31 (0) 15 2755 210
F: +31 (0) 15 2620 351
info@kippzonen.com
SALES OFFICES
Kipp & Zonen France S.A.R.L.
7 Avenue Clément Ader
ZA Ponroy - Bâtiment M
94420 Le Plessis Trévise
France
Kipp & Zonen Asia Pacific Pte. Ltd.
81 Clemenceau Avenue
#04-15/16 UE Square
Singapore 239917
Kipp & Zonen USA Inc.
125 Wilbur Place
Bohemia
NY 11716
United States of America
T: +33 (0) 1 49 62 41 04
F: +33 (0) 1 49 62 41 02
kipp.france@kippzonen.com
T: +65 (0) 6735 5033
F: +65 (0) 6735 8019
kipp.singapore@kippzonen.com
T: +1 (0) 631 589 2065
F: +1 (0) 631 589 2068
kipp.usa@kippzonen.com
Go to www.kippzonen.com for your local distributor or contact your local sales office
Passion for Precision
Source Exif Data:
File Type : PDF File Type Extension : pdf MIME Type : application/pdf Linearized : No Page Count : 36 PDF Version : 1.4 Title : KippZonen_Manual_CMP_CMA_series_Pyranometers_Albedometers_1007.pdf Author : Kipp & Zonen B.V. Producer : Mac OS X 10.6.8 Quartz PDFContext Create Date : 2012:05:03 19:58:44Z Modify Date : 2012:05:03 19:58:44ZEXIF Metadata provided by EXIF.tools