Campbell Scientific CMP3 User Manual

CMP3-L Pyranometer

Revision: 2/09

Copyright © 2006-2009

Campbell Scientific, Inc.

Warranty and Assistance

The CMP3-L PYRANOMETER 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

CAMPBELL SCIENTIFIC, INC. does not accept collect calls.

CMP3-L Pyranometer 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. Specifications ..............................................................1

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

4. Wiring............................................................................4

5. Example Programs......................................................5

5.1 Input Range...............................................................................................5

5.2 Multiplier..................................................................................................6

5.3 Offset........................................................................................................6

5.4 Example Programs....................................................................................7

5.4.1 CR1000 Example Program.............................................................7

5.4.2 CR10X Example Program ..............................................................8

5.5 Output Format Considerations..................................................................9

6. Maintenance...............................................................10

7. Troubleshooting ........................................................10

Figures

3-1. CMP3-L Pyranometer Attached to CM225 Solar Sensor Mounti ng Stand3

4-1. CMP3-L Schematic.................................................................................4

Tables

4-1. Differential Connections to Campbell Scientific Dataloggers ................4

4-2. Single-Ended Connections to Campbell Scientific Dataloggers.............5

5-1. Multipliers Required for Average Flux Density and Total Fluxes.......... 6

5-2. Wiring for Example Programs ................................................................7

i

CMP3-L Pyranometer

1. General Description

This manual provides information for interfacing the CMP3-L Pyranometer to
various models of Campbell Scientific dataloggers. The CMP3-L is
manufactured by Kipp & Zonen and then cabled by Campbell Scientific.
Cable length is user specified.

The CMP3-L is shipped with an instruction manual provided by Kipp & Zonen
that contains information concerning the CMP3-L’s construction, spectral
sensitivity, cosine response, and a simple sensor check out procedure.
Included with the sensor and manual is a calibration certificate with the sensor
calibration constant and serial number. Cross check this serial number against
the serial number on your CMP3-L to ensure that the given calibration constant
corresponds to your sensor.

The CMP3-L pyranometer is designed for continuous outdoor use. Due to its
flat spectral sensitivity from 300 to 3000 nm, it can be used in natural sunlight,
under plant canopies, in green houses or buildings, and inverted to measure
reflected solar radiation. Two CMP3-Ls can be used in combination to
measure albedo. The CMP3-L can also be used to measure most types of
artificial light (Xenon lamps, Halogen lamps, etc.).

The CMP3-L pyranometer consists of a thermopile sensor, housing, dome, and
cable. The thermopile is coated with a black absorbent coating. The paint
absorbs the radiation and converts it to heat. The resultant temperature
difference is converted to a voltage by the copper-constantan thermopile. The
thermopile is encapsulated in the housing in such a way that it has a field of
view of 180 degrees and the angular characteristics needed to fulfill the cosine
response requirements.

2. Specifications

The CMP3-L is an ISO Second Class pyranometer. While the worst case
accuracy for daily sums given by Kipp & Zonen is +
is +

ISO SPECIFICATIONS:
Response Time 95%: 18 seconds

Zero offset due to 200 W/m
radiation:

Zero offset due to temperature change
of 5ºK / hr:

Non stability (% change/year): < +
Non linearity (0 to 1000 W/m

Directional error (at 80º with
1000 W/m

5%.

2

beam):

2

thermal

2

):

10%, the typical accuracy

< 15 W m

< +

< +

< + 20 W m-2

-2

4 W m-2
1%

2.5%

1

CMP3-L Pyranometer

Temperature Dependence of
sensitivity:

Tilt response (+

OTHER SPECIFICATIONS

Expected accuracy for daily sums: +
Spectral range (50% points, nm): 310 to 2800 nm
Sensitivity:

Typical signal output for atmospheric
applications:

Impedance:
Operating Temperature: -40º to +80ºC
Max. irradiance:
Detector: Copper-constantan multi junction

Level accuracy: 1 degree
DIMENSIONS / SHIPPING DIMENSIONS
CMP3-L: 3 in dia x 4 in / 8x12x4 in

80º) (at 1000 W/m2):

5% (-10º to + 40ºC)

+

< +

2%

10%

5 to 20 μV W

0 to 15 mV
30 to 100 Ω

2000 Wm

thermopile

-1 m2

-2

3. Installation

WEIGHT/SHIPPING WEIGHT

CMP3-L: 1.2 lbs / 1.8 lbs

The CMP3-L is usually installed horizontally, but can also be installed at any
angle including an inverted position. In all cases it will measure the flu x that is
incident on the surface that is parallel to the sensor surface.

Site the CMP3-L to allow easy access for maintenance while ideally avoiding
any obstructions above the plane of the sensing element. It is important to
mount the CMP3-L such that a shadow will not be cast on it at any time.

If this is not possible, try to choose a site where any obstruction over the
azimuth range between earliest sunrise and latest sunset has an elevation not
exceeding 5°. Diffuse solar radiation is less influenced by obstructions near
the horizon. For instance, an obstruction with an elevation of 5° over the
whole azimuth range of 360° decreases the downward diffuse solar radiation
by only 0.8%.

The sensor should be mounted with the cable pointing towards the nearest
magnetic pole, e.g., in the Northern Hemisphere point the cable toward the
North Pole.

2