Kipp&Zonen CM 4 User Manual
CM 4
High Temperature Pyranometer
Instruction Manual
IMPORTANT USER INFORMATION
Reading this entire manual is recommended for full
understanding of the use of this product.
The exclamation mark within an equilateral triangle is in tended to alert the user
to the presence of important operating and main te nance instructio ns in the
literature accompanying the instrument.
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 Holland
P.O. Box 507 2600 AM Delft Holland
Phone +31 (0)15 2755210
Fax +31 (0)15 2620351
Email info@kippzonen.com
Web www.kippzonen.com
Kipp & Zonen reserve the right to make change s to the specifications w ithou t
prior notice.
WARRANTY AND LIABILITY
Kipp & Zonen guarantees that the product delivered has been thorough ly
tested to ensure that it meets its published specifications. The warranty
included in the conditions o f de li very is valid only if the product has been
installed and used according to the instructions supplie d by Kipp & Zonen.
Kipp & Zonen shall in no event be liable for inciden tal or con sequen tial
damages, including without li mi tation, lost profits, loss of income, loss o f
business opportunities, loss of use and o th er re lated exposures, however
caused, arising from the faulty and incorrec t use of th e product.
User made modifications can affect the validity of the CE declaration.
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COPYRIGHT© 2010 KIPP & ZONEN
All rights reserved. No part of this publication may be repro duced , store d in a
retrieval system or transmitted in any form or by any means, without
permission in written form from the company.
Manual version 1007
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CALIBRATION CERTIFICATE
The calibration certificate supplied with the instrument is valid from
the date of first use. Even though the calibration certificate is dated
relative to manufacture the instrument does not undergo any
sensitivity changes when kept in the original packing. From the
moment the instrument is taken from it’s packaging and exposed to
irradiance the sensitivity will deviate with time. See also the 'nonstability' performance (max. sensitivity change / year) given in the
radiometer specification list.
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DECLARATION OF CONFORMITY
According to EC guideline 89/336/EEC
We Kipp & Zonen B.V.
Delftechpark 36
2628 XH Delft
The Netherlands
Declare under our sole responsibility that the product
Type: CM 4
Name: High Temperature Pyranometer
To which this declaration relates is in conformity with the following standards
Imissions EN 50082-1 Group standard
Emissions EN 50081-1 Group standard
EN 55022
Following the provisions of the directive
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B.A.H. Dieterink
President
KIPP & ZONEN B.V.
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TABLE OF CONTENTS
IMPORTANT USER INFORMATION..............................................1
CALIBRATION CERTIFICATE.......................................................2
DECLARATION OF CONFORMITY ...............................................4
1 GENERAL INFORMATION........................................................9
1.1 INTRODUCTION ...................................................................9
1.2 PHYSICAL PRINCIPLES OF THE PYRANOMETER ....................10
1.2.1 Temperature Dependency...........................................11
1.2.2 Spectral properties of the glass dome.........................13
1.2.3 Directional / Cosine response......................................14
1.2.4 Non-linearity.................................................................15
2 LIST OF SPECIFICATIONS.....................................................17
3 INSTALLATION .......................................................................21
3.1 DELIVERY.........................................................................21
3.2 MECHANICAL INSTALLATION ..............................................21
3.2.1 Outdoor installation......................................................22
3.2.2 Indoor installation.........................................................22
3.3 ELECTRICAL CONNECTION .................................................23
4 OPERATION ........................................................................27
5 MAINTENANCE.......................................................................29
6 CALIBRATION ........................................................................31
6.1 INITIAL CALIBRATION..........................................................31
6.2 RECALIBRATION................................................................31
6.3 CALIBRATION PROCEDURE AT KIPP & ZONEN .....................33
6.3.1 The facility....................................................................33
6.3.2 Procedure ....................................................................33
6.3.3 Calculation...................................................................34
6.3.4 Zero offset....................................................................34
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6.3.5 Traceability to World Radiometric Reference..............35
7 FREQUENTLY ASKED QUESTIONS (FAQ’S).......................37
8 TROUBLE SHOOTING............................................................39
9 PART NUMBERS / SPARE PARTS / OPTIONS.....................41
APPENDIX I PYRANOMETER CLASSIFICATION
ACCORDING TO WMO GUIDE 1996............43
APPENDIX II PT-100 SPECIFICATIONS.............................45
APPENDIX III LIST OF WORLD AND REGIONAL
RADIATION CENTRES..................................47
APPENDIX IV RECALIBRATION SERVICE .........................49
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1. GENERAL INFORMATION
1 GENERAL INFORMATION
1.1 INTRODUCTION
The CM 4 High Temperature Pyranometer is an instrument for
measuring solar or artificial light irradiance. The instrument is
specially designed for usage under extreme irradiance and
temperature conditions. With an operating temperature range of
-40°C to +150°C and measurement up to 4000 W/m² it is a unique
product. All the radiometer components, including the signal cable,
are specially selected for their ability to withstand these extremely
high temperatures and irradiances.
In particular the CM4 has been developed for applications in an
industrial environment. The pyranometer is designed for both
continuous indoor and outdoor use. Because of the fact that it has a
flat spectral sensitivity from roughly 0.3 to 3 microns, its calibration is
valid for natural sunlight and for most types of artificial light (e.g.
Xenon lamps, halogen lamps).
CM 4 features:
• Robust and high temperature resistant construction and
cable
• Unique temperature compensation of sensor sensitivity
• Low non-linearity
• Exchangeable with meteorological field pyranometers
• Easy maintenance with easily accessible drying cartridge
• Built-in Pt-100 4-wire temperature sensor
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The CM 4 Pyranometer complies with specifications according to the
ISO 9060 standard, as defined in the ‘Guide to meteorological
Instruments and Methods of Observation’, sixth edition, 1996, of the
World Meteorological Organisation (WMO*) – Geneva – Switzerlan d.
* The WMO classification is adapted from the international standard
ISO 9060 (1990).
1.2 PHYSICAL PRINCIPLES OF THE PYRANOMETER
The pyranometer basically consists of a thermopile detector,
aluminium housing, a glass dome and a special cable. The CM4 is
provided with a Pt-100 temperature sensor to monitor the
pyranometer body temperature during operation. A drawing of the
pyranometer is shown in figure 1.1.
temperature sensor
Figure 1.1: CM 4 Pyranometer construction details.
Important: To avoid entry of water vapour it is strongly
glass dome
sensing element
housing
Circuit board
drying cartridge
recommended not to open the bottom plate of the
radiometer under any circumstances.
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1. GENERAL INFORMATION
The thermopile surface is coated with black absorbent paint.
Absorbed radiation is converted into heat which flows through the
thermal resistance of the thermopile to the heat-sink. The
temperature difference (ΔT) across the thermal resistance of the
detector is converted into a voltage.
Most electrical and physical specifications are determined by the
thermopile. The thermopile and the dome determine the spectral
specifications. The optimal geometry of both the glass dome and the
thermopile enables the pyranometer to have a 180° field of view with
good cosine response.
1.2.1 Temperature Dependency
One of the physical principles of a pyranometer is that at a constant
irradiance the detector sensitivity changes with the instrument
temperature. ISO 9060 defines this temperature response as the
percentage deviation due to a change in the ambient temperature
within a specific range of 50 K. The CM 4 temperature dependency
however is specified within an range of 170 K. To keep the
pyranometer performance acceptable the instrument output signal is
electrically compensated. Due to the perfectly balanced
thermoelectric construction the CM 4 temperature dependence is
kept within a deviation of 3%, within the range of -20 °C to 0 °C, 2%
within the range of 0 °C to +100 °C and 3% within the range of +100
°C to +150 °C .
After manufacturing, each instrument is individually checked for its
temperature dependency performance. This is measured in 8 steps
of 25 °C from -25 °C to +150 °C. A typical temperature response of
an electrically compensated CM 4 is given in figure 1.2.
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Temper ature dependenc y of the
sensitivity
3.000
2.000
1.000
0.000
[%]
-1.000
-2.000
Temperature dependency
-3.000
-40 -20 0 20 40 60 80 100 120 140 160
Instrument t e mperature ( ° C)
Figure 1.2: Typical temperature dependency curve of the CM 4.
The CM 4 High Temperature Pyranometer is supplied with its own
individual graph of temperature dependence of sensitivity. Monitoring
the temperature during operation will allow easy data correction
afterwards for improved measurement accuracy. The table in
Appendix II lists how to interpret the Pt-100 output readings.
To guarantee long-term stability the CM 4 circuitry consists of high
temperature resistant components, such that continuous high
irradiance measurements have a minimum effect on the durability or
the stability of the instrument.
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1.2.2 Spectral properties of the glass dome
The spectral properties of a pyranometer are determined by the
properties of the black absorbent paint and the glass dome. The
spectral response is given in figure 1.3.
1. GENERAL INFORMATION
Figure 1.3: The spectral transmission of the glass dome pyranometer
combined with the spectrum of the sun under a clear sky.
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1.2.3 Directional / Cosine response
The measurement of the radiation falling on a plane surface (also
called irradiance or radiative flux) requires two assumptions: that the
surface is spectrally black (that it absorbs all radiation of all
wavelengths) and that it has a 180° field of view. Another way of
expressing these directional properties is to say that the sensor has
to comply with an ideal cosine response. ISO 9060 defines the
cosine response (or directional response) as the range of errors
caused by assuming that the normal incidence responsitivity is valid
for all directions when measuring with a beam radiation whose
normal angle of incidence irradiance is 1000 W/m².
A perfect cosine response will show maximum sensitivity (1) at an
angle of incidence of 0° (perpendicular to the sensor surface) and
zero sensitivity at an angle of incidence of 90° (radiation passing
over the sensor surface). In between 0 and 90 degrees the sensitivity
should be proportional the cosine of the angle of incidence. Figure
1.4 shows the typical curve and the maximum percentage deviation
of a CM 4 pyranometer. The vertical axis shows the deviation from
ideal behaviour, expressed in percents of the ideal value.
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1. GENERAL INFORMATION
10
8
6
4
2
[%]
0
0 1020304050607080
-2
-4
-6
degrees
min. cosine error
%
typical cosine error
%
max. cosine error
%
Figure 1.4: The mean cosine response of the pyranometer. With the angle
of incidence on the horizontal axis and the percentage deviation
from ideal cosine behaviour on the vertical axis.
1.2.4 Non-linearity
Non-linearity is the error of the sensitivity variation as a function of
the variation in irradiance. ISO 9060 defines non-linearity of an
instrument as its percentage deviation from the responsitivity at 500
W/m² due to the change in irradiance within 100 W/m² to 1000 W/m².
The linearity however is strongly related to the pyranometer design
and body. Due to a thermal gradient over the hot and cold junctions
(by absorption of radiation) heat convection at the detector surface
causes a non-linearity effect. The CM 4 detector construction has
been designed to keep the thermal gradient very low. Even when the
pyranometer is exposed to a very intense artificial radiating source
the non-linearity of the sensor sensitivity is small. The CM 4 nonlinearity is show in figure 1.5.
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