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 [phone]
Fax [phone]
Email [e-mail]
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.

1

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

2

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.

3

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

4

B.A.H. Dieterink

President

KIPP & ZONEN B.V.

5

6

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

7

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

8

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

9

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.

10

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.

11

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.

12

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.

13

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.

14

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.

15

1.01

1.00

0.99

0.98

0.97

Relative error [-]

0.96
0 500 1000 1500 2000 2500

Irradiance [W/m²]

Figure 1.5: CM 4 non-linearity, sensitivity variation as a function of

the irradiance, with 500 W/m² as reference level during
calibration.

16

2 LIST OF SPECIFICATION S

Spectral range: 300 to 2800 nm, 50% points
Sensitivity: 7 µV/Wm
Impedance: 500 to 2000 Ω
Response time: 18 s (95% response)

< 8 s (63% response)
Non-linearity: Max. 3 % (0 - 2500 W/m
Directional error (at 80°

with a 1000 W/m² beam): ± 20 W/m²
Temperature dependence

of sensitivity: 3 % (-20 °C to +0 °C)
2 % (0 °C to +100 °C)
3 % (+100 °C to +150 °C)

Tilt error: Max. 1% deviation when facing
downwards
Zero-offset due to
temperature changes: Max. 4 W/m

change.

Zero-offset due to FIR
(200 W/m

Operating temperature: -40 °C to +150 °C
Field of view: 180° (2 π sr)
Max irradiance: 4000 W/m
Non-stability: ± 1% sensitivity change per year

2

): ± 15 W/m2

SPECIFICATIONS

-2

(nominal)

2

)

2

offset for 5 K/h temp.

2

17

Temperature sensor: Pt-100

Construction:

Receiver paint: Carbon Black
Dome: Glass
Desiccant: Silica gel
Materials: Anodised aluminium case

Stainless steel screws etc
Viton O-rings
Drying cartridge aluminium and glass lid

Cable material: 6-wire shielded cable
Pt-100 specifications: Type Heraeus M-GX 1013, DIN

IEC 751. Class A, See Appendix II
Shock / vibration: IEC 721-3-2-2m2
CE according to EC guideline

89/336/EEC 73/23/EEC
Environmental: Intended for continuous outdoor or

indoor use.

Humidity 0 - 100% RH
Weight: 200 g
Cable length: Standard 10 m;
Dimensions in mm: See figure 2.1

18

Figure 2.1: CM 4 Dimensions.

SPECIFICATIONS

19

20

3. INSTALLATION

3 INSTALLATION

Reading the installation instruction before installation is
recommended for full understanding of the use of this product.

3.1 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, and also if the contents are incomplete, your dealer should
be notified in order to facilitate the repair or replacement of the
instrument.

The CM 4 pyranometer delivery will include the following items:

1. CM 4 pyranometer

2. Calibration certificate

3. Manual

4. Temperature dependency data

5. 2 x desiccant packs

Unpacking

Keep the original packaging for later shipments!
Although all sensors are weatherproof and suitable for rough
ambient conditions, they do partially consist of delicate mechanical
parts. For this type of equipment, keep the original shipment
packaging to safely transport the equipment to the measurement
site.

3.2 MECHANICAL INSTALLATION

The mechanical installation of the pyranometer depends upon the
measurement purpose. Different measurement methods are
explained in the next sections.

21

3.2.1 Outdoor installation

When installed permanently, the pyranometer can be attached to its
mounting platform by means of the holes that are drilled through the
body, see figure 2.1.
Preferred orientation is with the cable pointing to the nearest pole.
When installed on a mast, preferred orientation is such that no
shadow is cast on the pyranometer during any time of the day. In the
Northern hemisphere this implies that the pyranometer should be
south of the mast.

The pyranometer can be used to measure reflected radiation, for
instance when pointed towards the earth in the inverted position.
When measuring reflected radiation (as an albedometer) it is advised
to do this at a height of at least 1.5 meters above the surface, to
avoid shading effects and to promote spatial averaging.

3.2.2 Indoor installation

When continuously used for indoor purposes the instrument should
preferably be attached to a mounting platform by means of the holes
that are drilled through the body, see figure 2.1. However, this might
not always be possible, for instance if the instrument is relocated or
moved regularly. What is recommended in these cases is to relocate
the instrument in the same place as much as possible, attempting to
repeat the same measurement conditions e.g. with respect to a fixed
offset from a light reflecting wall or any other object.

In the case of measuring the light irradiance on tilted surfaces it is
recommended to tilt and fix the radiometer at the same inclination as
the surface.

22

3. INSTALLATION

3.3 ELECTRICAL CONNECTION

The CM 4 is provided with a special 10 m cable with six leads and a
shield covered with a black sleeve.

The colour code is: red = plus
blue = minus
Shield = case

Pt-100 temperature sensor (4 – wire connection)

White: Pt 100 (combined with black)
Black: Pt 100 (combined with white
Green: Pt 100 (combined with yellow)
Yellow: Pt 100 (combined with green)

The shield is directly connected to the case. Preferably the shield
should be connected to the same ground at the readout equipment,
to reduce cable noise. The cable must be firmly secured to minimise
spurious response during any mechanical movement or vibration
(pressing the cable produces voltage spikes, a tribo-electric effect
and capacitance effect).

Looking at the circuit diagram of figure 3.1, it is clear that the
impedance of the readout equipment is loading the thermistor circuit
and the thermopile. This can increase the temperature dependency
of the pyranometer. The sensitivity is affected more than 0.1% when
the load resistance is less than 1.5 MΩ. For this reason we
recommend the use of readout equipment with an input impedance
of 1.5 MΩ or more, such as potentiometric recorders, digital
voltmeters, etc. The solar integrators and chart recorders available
from Kipp & Zonen meet these requirements. Extension cables may
be used, but the cable resistance must be smaller than 0.1% of the
impedance of the readout equipment.

23

Figure 3.1: Circuit diagram of the CM 4 Pyranometer and connection to

readout equipment.

It is evident that application of attenuator circuits to the CM 4 output
in order to modify the calibration factor is not recommended because
the temperature response will also be affected. However, recorders
with a variable voltage range can be set so that the result can be
read out directly in W/m

2

.

A considerable input bias current in the readout equipment can
produce a voltage of several micro-volts across the impedance of the
pyranometer. The correct measured zero signal can be verified with
a resistance replacing the pyranometer impedance at the input
terminals.

With the availability of a low voltage analogue input module with A/D
converter the pyranometer can be connected to a computer or data
acquisition system. The span and resolution of the A/D converter in
the module must allow a system sensitivity of about 1 bit per W/m

2

.

24

3. INSTALLATION

For amplification of the pyranometer signal Kipp & Zonen
recommends the 4-20 mA Signal Amplifier, available from Kipp &
Zonen. This amplifier converts the micro-Volt output from the
pyranometer into a standard 4–20 mA signal.
Zero and Span adjustment of the pyranometer signal are provided.

25

26

4. OPERATION

4 OPERATION

After completing the installation the pyranometer will be ready for
operation.

The irradiance value (E) can be simply computed by dividing the
output signal (U

) of the pyranometer by its sensitivity (S

emf

ensitivity

) as
shown in formula 1, or by multiplication of the voltage value with the
reciprocal of the sensitivity, often called the calibration factor. The
CM 4 pyranometer sensitivity is given in the supplied calibration
certificate.

For calculation of the solar irradiance the following formula must be
applied:

U

E

=

S

ensitivity

emf

(Formula 1)

E = Global radiation [W/m

= Output of pyranometer [μV]

U

emf

S

= Sensitivity of pyranometer [μV/W/m2]

ensitivity

2

]

27

28

5. MAINTENANCE

5 MAINTENANCE

Once installed the pyranometer needs little maintenance. The
pyranometer dome must be kept clean and inspected regularly.

Ensure that the silica gel 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 active silicagel
as supplied in the small refill packs. The content of one pack is
sufficient for one complete refill.

In humid areas it is usual to replace the desiccant twice a year.
The replacement interval is affected by humidity, variations in air
pressure and the extent of temperature changes.

Some tips when changing the desiccant:

- Do not remove the desiccant cartridge unnecessarily.

- Dirt in combination with water is the main cause of corrosion.

Make sure the surfaces of the pyranometer and the cartridge
that touch the rubber sealing ring are clean.

- For a better seal, the rubber ring is normally coated with

silicon grease (Vaseline can also be used). If the rubber ring
looks dry apply some grease to it.

29

30

6. CALIBRATION

6 CALIBRATION

6.1 INITIAL CALIBRATION

The ideal pyranometer should always have a constant ratio of
voltage output to irradiance level (outside the instrument in the plane
of the sensing element). This ratio is called sensitivity (S

ensitivity

) or

responsivity.
The calibration (sensitivity) factor of a particular pyranometer is

unique. It is determined in the manufacturer's laboratory by
comparison against a reference pyranometer.
The reference pyranometer is regularly calibrated outdoors at the
World Radiation Centre in Davos, Switzerland. Of course the
spectral content of the laboratory lamp differs from the outdoor solar
spectrum at the Radiation Centre. However, this has no
consequences for the transfer of calibration, because the reference
pyranometer and the pyranometer under test have the same black
coating and glass dome.

The supplied calibration factor is determined under the following
conditions:

 An ambient temperature of 20°C.
 For a horizontal pyranometer as well as for a tilted pyranometer.
 Normal incident radiation of 500 W/m

2

.

 Spectral content the same as clear sky solar radiation.

6.2 RECALIBRATION

The pyranometer sensitivity changes with time and with exposure to
radiation, this deviation is also known as the non-stability.
Periodically a radiometer calibration is advised, at least every two
years. Recalibration can be done at Kipp & Zonen. When sending
back a pyranometer to Kipp & Zonen for recalibration it is
recommended to use the recalibration form in the back of this
manual, Appendix IV.

31

Accurate calibrations can also be done outdoors under clear
conditions by comparison to a reference pyrheliometer. Many
National Weather Services have calibration facilities. Their standard
pyrheliometer is compared with the World Radiometric Reference
(maintained at Davos, Switzerland) embodied by several absolute
pyrheliometers (black body cavity type).
The comparisons are performed indoors or outdoors at one of the
regional Radiation Centres, see Appendix III. These institutes
sometimes offer calibration services.

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 pyranometer to be
calibrated 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 irradiance 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 recalibrate a pyranometer. The latter is
extensively described in International standard ISO 9846. A
summary of calibration methods is also found in the WMO guide of

1996.
Another procedure to recalibrate pyranometers is described in the

International Standard ISO 9847. Here the pyranometer to be
calibrated is compared to a reference pyranometer under clear sky
conditions. 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.

32

6. CALIBRATION

6.3 CALIBRATION PROCEDURE AT KIPP & ZONEN

6.3.1 The facility

The calibration facility at Kipp & Zonen consists of a good quality film
sun (Osram) fed by an AC voltage stabiliser. This is used as an
artificial sun. It embodies a 150 W Metal Halide lamp with compact
filament.

To minimise stray light from the walls and the operator, the light is
limited to a small cone around the two pyranometers. The unknown
pyranometer 'a' and the standard pyranometer 'b' are placed side by
side on a small table. The table can rotate to interchange the
positions (1 and 2) of the pyranometers. 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
pyranometers (3°) so this cannot give rise to errors. The two
pyranometers are not levelled with the screws, but placed on their
bases. The effect of a small tilt is almost zero (Compare cos. 3° =

0.9986 and cos. 4° = 0.9976). The irradiance of the pyranometers is
approx. 500 W/m

2

. The colour temperature of the light is 3300 K.

6.3.2 Procedure

After illuminating for 70 s, the output voltages of both pyranometers
are integrated over 20 s with a solar integrator. Next, a blackened
‘hat’ covers both pyranometers. After 70 s the zero offset signal of
both pyranometers is integrated again.

The problem of the zero offset is described below. This zero offset
has to be subtracted to obtain the response due to illumination. So
we get responses A and B respectively.

The irradiance at position 1 (pyranometer 'a') may be slightly
different from that at position 2 (pyranometer 'b') due to asymmetry in

33

+

the lamp optics etc. Therefore the pyranometers are interchanged
and the whole procedure is repeated. We get another pair of values:
A' and B'.

6.3.3 Calculation

The sensitivity of the unknown pyranometer is calculated using
formula 2:

=

+

(Formula 2)

⋅

sS

ba

'

BB

'

AA

Sb = Sensitivity of the reference pyranometer at 20 °C.
A = Output of test pyranometer at position 1
A’ = Output of test pyranometer at position 2
B = Output of reference pyranometer at position 2
B’ = Output of reference pyranometer at position 1
S

= Sensitivity of the test pyranometer at 20 °C.

a

Output = mean value at 100% response minus zero offset signal

6.3.4 Zero offset

The lamp housing and diaphragms are emitting long wave infrared
radiation, which heats up the glass dome. When the pyranometers
are shaded, there still remains a small signal up to + 20 µV due to
longwave infrared radiation from the 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 70 s
shading is subtracted.

34

6. CALIBRATION

6.3.5 Traceability to World Radiometric Reference

Working reference pyranometers are maintained at Kipp & Zonen.
Each reference pyranometer is characterised. Linearity, temperature
dependence curve and directional response are well kno wn.

The working reference pyranometers are calibrated each year at the
World Radiation Center in Davos, Switzerland, according to the
component method.

35

36

7 FREQUENTLY ASKED QUESTIONS

7 FREQUENTLY ASKED QUESTIONS (FAQ’s)

The most frequently asked questions are listed below.

1. Negative output during measurements?

This error is related to the zero offset type A. Normally this zero
offset is present when the dome has a different temperature from the
cold junctions of the sensor. In practice this is always the case when
there is very large and cold object close to the pyranometer. The
emitted heat by the glass dome is attracted from the body (by
conduction in the dome) and from the air (by convection and heat
conductivity). The 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 the
absorbed solar radiation and causes the well known zero
depression. This negative zero offset is always present, however,
hidden within the thermopile signal.

2. What is the primary entry point for humidity?

The desiccant cartridge and cable gland have equal chances to
transport some moisture. Also the silicon glue of the domes is not
completely watertight.

When care is not taken one can easily make the desiccant
cartridge the primary entry point. See chapter 5 for the
maintenance of the CM 4 Pyranometer.

Note: Water vapour transport through the cable is also possible when

the open end of the cable at the readout device is in a humid
environment.

37

38

8 TROUBLE SHOOTING

8 TROUBLE SHOOTING

The following contains a procedure for checking the instrument in
case it appears that it does not function as one could expect.

Trouble shooting:
Output signal fails or shows improbable results:
 Check the wires, whether they are properly connected to the

readout equipment.

 Check the dome and the drying cartridge, they should be clear. If

water is deposited on the inside, please change the desiccant. If
too much water is deposited the instrument should be dried
internally.

 Check the instrument impedance (500 - 2000 Ohm)
 Check datalogger or integrator offset by connecting a dummy

load (500 - 2000 Ohm resistor). This should give a “zero”
reading.

If water or ice is deposited to the outside of the dome, clean the
dome. Usually water droplets will evaporate in less than one hour.

Any visible damage or malfunction should be reported to your dealer,
who will suggest appropriate action.

39

40

9 PART NUMBERS / SPARE PARTS / OPTIONS

9 PART NUMBERS / SPARE PARTS / OPTIONS

Description Part no.

Drying Cartridge kit 0356 111
(incl. Cartridge, Cover, Rubber Ring)

Silica gel refill pack 2643 951

41

42

APPENDIX I PYRA NOMETER CLASSIFICATION

ACCORDING TO WMO GUIDE 1996

Characteristics

ISO 9060 classification
Response time (95 percent response) < 15 s < 30 s < 60 s

Zero offset:
(a) Response to 200 W/m

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/m

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/m
due to any change of irradiance
within the range 100 to 1000 W/m

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 μm)

Tilt response (percentage deviation
from the responsivity at 0° tilt,
horizontal, due to change in tilt from
0° to 90° at 1000 W/m

2

2

irradiance)

2

)

2

2

High

quality

Secondary

standard

± 7 W/m

± 2 W/m

± 1 W/m

± 0.8 ± 1.5 ± 3.0

± 10 W/m

± 2 ± 4 ± 8

± 0.5 ± 1 ± 3

)

± 2 ± 5 ± 10

± 0.5 ± 2 ± 5

Good

quality

First class Second class

2

2

2

± 15 W/m

± 4 W/m

± 5 W/m2 ± 10 W/m2

2

± 20 W/m2 ± 30 W/m2

2

2

Moderate

quality

± 30 W/m

± 8 W/m

2

2

43

Achievable uncertainty, 95 percent
confidence level

Hourly totals
Daily totals

3%
2%

8%
5%

20%
10%

44

APPENDIX II PT-100 SPECIFICATIONS

Temp.

[°C]

-40

-39

-38

-37

-36

-35

-34

-33

-32

-31

-30

-29

-28

-27

-26

-25

-24

-23

-22

-21

-20

-19

-18

-17

-16

-15

-14

-13

-12

-11

-10

-9

Resistance

[Ω]

84,27
84,67
85,06
85,46
85,85
86,25
86,64
87,04
87,43
87,83
88,22
88,62
89,01
89,40
89,80
90,19
90,59
90,98
91,37
91,77
92,16
92,55
92,95
93,34
93,73
94,12
94,52
94,91
95,30
95,69
96,09
96,48

Temp.

[°C]

-8

-7

-6

-5

-4

-3

-2

-1
0
1
2
3
4
5
6
7
8
9

10
11
12
13
14
15
16
17
18
19
20
21
22
23

Resistance

[Ω]

96,87
97,26
97,65
98,04
98,44
98,83
99,22

99,61
100,00
100,39
100,78
101,17
101,56
101,95
102,34
102,73
103,12
103,51
103,90
104,29
104,68
105,07
105,46
105,85
106,24
106,63
107,02
107,40
107,79
108,18
108,57
108,96

Temp.

[°C]

24
25
26
27
28
29
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

Resistance

[Ω]

109,35
109,73
110,12
110,51
110,90
111,29
111,67
112,06
112,45
112,83
113,22
113,61
114,00
114,38
114,77
115,15
115,54
115,93
116,31
116,70
117,08
117,47
117,86
118,24
118,63
119,01
119,40
119,78
120,17
120,55
120,94
121,32

45

Temp.

[°C]

Resistance

[Ω]

Temp.

[°C]

Resistance

[Ω]

Temp.

[°C]

Resistance

[Ω]

56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87

121,71
122,09
122,47
122,86
123,24
123,63
124,01
124,39
124,78
125,16
125,54
125,93
126,31
126,69
127,08
127,46
127,84
128,22
128,61
128,99
129,37
129,75
130,13
130,52
130,90
131,28
131,66
132,04
132,42
132,80
133,18
133,57

88
89
90
91
92
93
94
95
96
97
98

99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119

133,95
134,33
134,71
135,09
135,47
135,85
136,23
136,61
136,99
137,37
137,75
138,13
138,51
138,88
139,26
139,64
140,02
140,40
140,78
141,16
141,54
141,91
142,29
142,67
143,05
143,43
143,80
144,18
144,56
144,94
145,31
145,69

120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150

146,07
146,44
146,82
147,20
147,58
147,95
148,33
148,70
149,08
149,46
149,83
150,21
150,58
150,96
151,33
151,71
152,08
152,46
152,83
153,21
153,58
153,96
154,33
154,71
155,08
155,46
155,83
156,20
156,58
156,95
157,33

46

APPENDIX III LIST OF WORLD AND REGIONAL

RADIATION CENTRES

World Radiation Centres
St. Petersburg (Russia)

Regional Radiation Centres
Region I Africa: Cairo (Egypt)

Khartoum (Sudan)
Kinshasa (Zaire)
Lagos (Nigeria)
Tamanrasset (Algeria)
Tunis (Tunisia)

Region II Asia: Poona (India)
Tokyo (Japan)

Region III South America: Buenos Aires
(Argentina)

Region IV North and Central America: Toronto (Canada)

Washington (U.S.A.)
Region V South West Pacific: Aspendale (Australia)
Region VI Europe: Bracknell (United Kingdom)

Budapest (Hungary)
Davos (Switzerland)
St. Petersburg (Russia)
Norrköping (Sweden)
Trappes/Carpentras
(France)

Davos (Switzerland)

Uccle (Belgium)
MOH Hamburg (Germany

47

48

APPENDIX IV RECALIBRATION SERVICE

Pyranometers, UV-meters, Pyrgeometers &

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 at least 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 your convenience we have attached three fax forms to schedule
the recalibration of your instrument(s) at Kipp & Zonen.

49

50

Name :
Company/Institute :
Address :
Postcode + City :
Country :
Phone :
Fax :
E-mail :

RECALIBRATION FORM

 I would like to receive a price estimate for recalibration
 I would like to submit my instruments for recalibration

Type/Model: Qty: Requested deliv ery time

Conformation by Kipp & Zonen

□ Yes, the dates are acceptable to us

I intend to send the instrument(s) to

Kipp & Zonen on:

. . . . . ./. . . . . ./. . . . . .

I would like to receive the instrument(s)

back on:

. . . . . ./. . . . . ./. . . . . .

□ No, unfortunately the dates do not fit into our calibration

schedule. We suggest the following dates:

. . . . . ./. . . . . ./. . . . . .

. . . . . ./. . . . . ./. . . . . .

Fax: [phone] or mail to:

Kipp & Zonen, P.O. Box 507, 2600AM Delft, The

Netherlands

51

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.

HEA D OFFICE

Kipp & Zonen B.V.

Delftechpark 36, 2628 XH Delft
P.O. Box 507, 2600 AM Delft
The Netherlands

T: [phone]
F: [phone]
[e-mail]

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

Go to www.kippzonen.com for your local distributor or contact your local sales office

T:

[phone]
F: [phone]
[e-mail]

T: [phone]
F: [phone]
[e-mail]

T: [phone]
F: [phone]
[e-mail]

Passion for Precision