Campbell Scientific CNR2 User Manual

CNR2 Net Radiometer

Revision: 5/10

Copyright © 2000-2010

Campbell Scientific, Inc.

Warranty and Assistance

The CNR2 NET RADIOMETER is warranted by CAMPBELL
SCIENTIFIC, INC. to be free from defects in materials and workmanship
under normal use and service for twelve (12) months from date of shipment
unless specified otherwise. Batteries have no warranty. CAMPBELL
SCIENTIFIC, INC.'s obligation under this warranty is limited to repairing or
replacing (at CAMPBELL SCIENTIFIC, INC.'s option) defective products.
The customer shall assume all costs of removing, reinstalling, and shipping
defective products to CAMPBELL SCIENTIFIC, INC. CAMPBELL
SCIENTIFIC, INC. will return such products by surface carrier prepaid. This
warranty shall not apply to any CAMPBELL SCIENTIFIC, INC. products
which have been subjected to modification, misuse, neglect, accidents of
nature, or shipping damage. This warranty is in lieu of all other warranties,
expressed or implied, including warranties of merchantability or fitness for a
particular purpose. CAMPBELL SCIENTIFIC, INC. is not liable for special,
indirect, incidental, or consequential damages.

Products may not be returned without prior authorization. The following
contact information is for US and International customers residing in countries
served by Campbell Scientific, Inc. directly. Affiliate companies handle
repairs for customers within their territories. Please visit
www.campbellsci.com to determine which Campbell Scientific company
serves your country.

To obtain a Returned Materials Authorization (RMA), contact CAMPBELL
SCIENTIFIC, INC., phone [phone]. After an applications engineer
determines the nature of the problem, an RMA number will be issued. Please
write this number clearly on the outside of the shipping container.
CAMPBELL SCIENTIFIC's shipping address is:

CAMPBELL SCIENTIFIC, INC.

RMA#_____
815 West 1800 North
Logan, Utah 84321-1784

For all returns, the customer must fill out a “Declaration of Hazardous Material
and Decontamination” form and comply with the requirements specified in it.
The form is available from our website at
completed form must be either emailed to [e-mail]
435-750-9579. Campbell Scientific will not process any returns until we
receive this form. If the form is not received within three days of product
receipt or is incomplete, the product will be returned to the customer at the
customer’s expense. Campbell Scientific reserves the right to refuse service on
products that were exposed to contaminants that may cause health or safety
concerns for our employees.

www.campbellsci.com/repair

. A

or faxed to

CNR2 Table of Contents

PDF viewers note: These page numbers refer to the printed version of this document. Use
the Adobe Acrobat® bookmarks tab for links to specific sections.

1. General Description.....................................................1

2. Sensor Specifications.................................................1

2.1 CNR2 Specifications ................................................................................1

2.2 Pyranometer Specifications......................................................................2

2.3 Pyrgeometer Specifications......................................................................2

3. Installation....................................................................2

4. Using the CNR2 in the Two Separate Components

Mode (2SCM).............................................................5

4.1 Measuring Solar Radiation with the Pyranometers ..................................5

4.2 Measuring Far Infrared Radiation with the Pyrgeometers........................5

4.3 Calculation of the Net Solar Radiation.....................................................6

5. Wiring............................................................................6

6. Datalogger Programming............................................7

6.1 Calibration Factor.....................................................................................8

6.2 Example Programs....................................................................................8

6.2.1 Example Program for CR1000 Datalogger.....................................8

6.2.2 Example Program for CR10X Datalogger......................................9

7. Calibration..................................................................11

8. Maintenance...............................................................12

9. Typical Values............................................................13

Figures

2-1. The Dimensions of the CNR2.................................................................2

3-1. Mounting According to Hemisphere.......................................................3

3-2. The CNR2 mounted to a pole (top) and crossarm (bottom) via

the 26120 Mounting Bracket Kit..........................................................4

5-1. Pin Layout on Campbell Scientific Black Cable.....................................6

5-2. Pin Layout on Kipp & Zonen Original Cable .........................................7

i

CNR2 Table of Contents

Tables

8-1. Dirt, Rain, or Snow on CNR2 Sensor will Reduce the Readings......... 12

8-2. CNR2 Net Radiometer Bubble-Level................................................... 13

8-3. Replacing Drying Cartridge.................................................................. 13

5-1. CRBasic Datalogger Connections for Differential Measurement........... 6

5-2. Edlog Datalogger Connections for Differential Measurement............... 7

5-3. Campbell Scientific Cable vs. Kipp & Zonen Cable.............................. 7

9-1. Typical Values from CNR2 Net Radiometer........................................ 13

ii

CNR2 Net Radiometer

1. General Description

The CNR2 Net Radiometer is intended for the analysis of the radiation balance
of short-wave and long-wave infrared radiation. The most common application
is the measurement of total net radiation at the earth's surface.

The CNR2 design is such that both the upward facing and the downward­facing instruments measure the energy that is received from the hemisphere.
The short-wave sensor, or pyranometer, has a field of view of 180 degrees on
the upper and 150 degrees on the lower detector. The long wave sensor, or
pyrgeometer, has a field of view of 150 degrees on the upper and the lower
detector. The output is expressed in Watts per square meter. The total spectral
range that is measured is roughly from 0.3 to 40 micrometers. This spectral
range covers both the solar radiation, 0.3 to 2.8 micrometers, and the far
infrared radiation, 4.5 to 42 micrometers.

The design of the CNR2 is such that short-wave radiation and long-wave
radiation are measured separately. Short-wave radiation is measured by two
pyranometers, one for measuring incoming short-wave radiation from the sky,
and the other, which faces downward, for measuring the reflected short-wave
radiation. The final result from these two pyranometers is net short-wave
radiation.

Long-waveradiation is measured by two pyrgeometers, one for measuring the
long-wave radiation from the sky, the other from the soil surface. Net long­wave radiation is a final result of measurements from those two detectors.

Additional information on the CNR2 sensor can be found in the Kipp & Zonen
CNR2 Manual. The primary intent of this manual is to provide information on
interfacing the CNR2 to Campbell Scientific dataloggers.

2. Sensor Specifications

2.1 CNR2 Specifications

Response time: <10s
Temperature dependence of

sensitivity (-10°C to +40°C): <5%
Sensor asymmetry: <5%
Sensitivities: 10 to 20 μV/W/m
Sensitivity change per year: <1%
Tilt error: <1%
Uncertainty in daily total: <10%
Cable length:

Weight:

2

Customer’s choice from 3 to 100 ft.
(Recommended are 50, 75, and 100 ft)

250 g (add about 300g for each
30ft of cable)

1

CNR2 Net Radiometer

2.2 Pyranometer Specifications

FIGURE 2-1. The Dimensions of the CNR2

2.3 Pyrgeometer Specifications

3. Installation

Spectral range:
Zero offset: Type A; 200 W/m

2

FIR
Field of view for upper detector:
Field of view for lower detector:
Directional error:
Non-linearity (0-1000 W m

-2

) net

irradiance:

Spectral range:
Field of view of upper detector:
Field of view of lower detector:
Non-linearity (-250 to +250 W m

net irradiance:

310 to 2800 nm
<15 W/m
180°
150°
<20 W m

<2.0%

4.5 to 42 µm
150°
150°

-2

)

<1%

2

-2

2

For measurement of the net radiation, it is important that the instrument is
located in a place that is representative of the entire study region.

Install the CNR2 such that no shadow is cast on the net radiometer at any time
during the day. In the Northern Hemisphere, mount the CNR2 south of the
mast. In the Southern Hemisphere, mount the CNR2 north of the mast (see
Figure 3-1).