INSTRUCTION MANUAL
CPEC200 Closed-Path
Copyright © 2013- 2014
Campbell Scientific, Inc.
Eddy-Covariance System
Revision: 7/14
Limited Warranty
“Products manufactured by CSI are warranted by CSI to be free from defects in
materials and workmanship under normal use and service for twelve months
from the date of shipment unless otherwise specified in the corresponding
product manual. (Product manuals are available for review online at
www.campbellsci.com.) Products not manufactured by CSI, but that are resold
by CSI, are warranted only to the limits extended by the original manufacturer.
Batteries, fine-wire thermocouples, desiccant, and other consumables have no
warranty. CSI’s obligation under this warranty is limited to repairing or
replacing (at CSI’s option) defective Products, which shall be the sole and
exclusive remedy under this warranty. The Customer assumes all costs of
removing, reinstalling, and shipping defective Products to CSI. CSI will return
such Products by surface carrier prepaid within the continental United States of
America. To all other locations, CSI will return such Products best way CIP
(port of entry) per Incoterms ® 2010. This warranty shall not apply to any
Products which have been subjected to modification, misuse, neglect, improper
service, accidents of nature, or shipping damage. This warranty is in lieu of all
other warranties, expressed or implied. The warranty for installation services
performed by CSI such as programming to customer specifications, electrical
connections to Products manufactured by CSI, and Product specific training, is
part of CSI's product warranty. CSI EXPRESSLY DISCLAIMS AND
EXCLUDES ANY IMPLIED WARRANTIES OF MERCHANTABILITY
OR FITNESS FOR A PARTICULAR PURPOSE. CSI hereby disclaims,
to the fullest extent allowed by applicable law, any and all warranties and
conditions with respect to the Products, whether express, implied or
statutory, other than those expressly provided herein.”
Assistance
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 (435) 227-9000. After an application 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 “Statement of Product Cleanliness
and Decontamination” form and comply with the requirements specified in it.
The form is available from our web site at www.campbellsci.com/repair. A
completed form must be either emailed to repair@campbellsci.com or faxed to
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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.
Precautions
DANGER — MANY HAZARDS ARE ASSOCIATED WITH INSTALLING, USING, MAINTAINING, AND WORKING ON OR AROUND
TRIPODS, TOWERS, AND ANY ATTACHMENTS TO TRIPODS AND TOWERS SUCH AS SENSORS, CROSSARMS, ENCLOSURES,
ANTENNAS, ETC. FAILURE TO PROPERLY AND COMPLETELY ASSEMBLE, INSTALL, OPERATE, USE, AND MAINTAIN TRIPODS,
TOWERS, AND ATTACHMENTS, AND FAILURE TO HEED WARNINGS, INCREASES THE RISK OF DEATH, ACCIDENT, SERIOUS
INJURY, PROPERTY DAMAGE, AND PRODUCT FAILURE. TAKE ALL REASONABLE PRECAUTIONS TO AVOID THESE HAZARDS.
CHECK WITH YOUR ORGANIZATION'S SAFETY COORDINATOR (OR POLICY) FOR PROCEDURES AND REQUIRED PROTECTIVE
EQUIPMENT PRIOR TO PERFORMING ANY WORK.
Use tripods, towers, and attachments to tripods and towers only for purposes for which they are designed. Do not exceed design
limits. Be familiar and comply with all instructions provided in product manuals. Manuals are available at www.campbellsci.com or
by telephoning 435-227-9000 (USA). You are responsible for conformance with governing codes and regulations, including safety
regulations, and the integrity and location of structures or land to which towers, tripods, and any attachments are attached. Installation
sites should be evaluated and approved by a qualified engineer. If questions or concerns arise regarding installation, use, or
maintenance of tripods, towers, attachments, or electrical connections, consult with a licensed and qualified engineer or electrician.
General
• Prior to performing site or installation work, obtain required approvals and permits. Comply
with all governing structure-height regulations, such as those of the FAA in the USA.
• Use only qualified personnel for installation, use, and maintenance of tripods and towers, and
any attachments to tripods and towers. The use of licensed and qualified contractors is highly
recommended.
• Read all applicable instructions carefully and understand procedures thoroughly before
beginning work.
• Wear a hardhat and eye protection, and take other appropriate safety precautions while
working on or around tripods and towers.
• Do not climb tripods or towers at any time, and prohibit climbing by other persons. Take
reasonable precautions to secure tripod and tower sites from trespassers.
• Use only manufacturer recommended parts, materials, and tools.
Utility and Electrical
• You can be killed or sustain serious bodily injury if the tripod, tower, or attachments you are
installing, constructing, using, or maintaining, or a tool, stake, or anchor, come in contact with
overhead or underground utility lines.
• Maintain a distance of at least one-and-one-half times structure height, or 20 feet, or the
distance required by applicable law, whichever is greater, between overhead utility lines and
the structure (tripod, tower, attachments, or tools).
• Prior to performing site or installation work, inform all utility companies and have all
underground utilities marked.
• Comply with all electrical codes. Electrical equipment and related grounding devices should
be installed by a licensed and qualified electrician.
Elevated Work and Weather
• Exercise extreme caution when performing elevated work.
• Use appropriate equipment and safety practices.
• During installation and maintenance, keep tower and tripod sites clear of un-trained or non-
essential personnel. Take precautions to prevent elevated tools and objects from dropping.
• Do not perform any work in inclement weather, including wind, rain, snow, lightning, etc.
Maintenance
• Periodically (at least yearly) check for wear and damage, including corrosion, stress cracks,
frayed cables, loose cable clamps, cable tightness, etc. and take necessary corrective actions.
• Periodically (at least yearly) check electrical ground connections.
WHILE EVERY ATTEMPT IS MADE TO EMBODY THE HIGHEST DEGREE OF SAFETY IN ALL CAMPBELL SCIENTIFIC PRODUCTS,
THE CUSTOMER ASSUMES ALL RISK FROM ANY INJURY RESULTING FROM IMPROPER INSTALLATION, USE, OR
MAINTENANCE OF TRIPODS, TOWERS, OR ATTACHMENTS TO TRIPODS AND TOWERS SUCH AS SENSORS, CROSSARMS,
ENCLOSURES, ANTENNAS, ETC.
Table of Contents
PDF viewers: These page numbers refer to the printed version of this document. Use the
PDF reader bookmarks tab for links to specific sections.
1. Introduction ................................................................. 1
2. Cautionary Statements ............................................... 1
3. Initial Inspection ......................................................... 2
4. Overview ...................................................................... 2
4.1 System Components ............................................................................. 2
4.1.1 Standard Components ................................................................... 2
4.1.1.1 EC155 Gas Analyzer .......................................................... 2
4.1.1.2 EC100 Electronics .............................................................. 3
4.1.1.3 CPEC200 Enclosure ........................................................... 3
4.1.1.4 CPEC200 Pump Module .................................................... 4
4.1.2 Optional Components ................................................................... 4
4.1.2.1 CR3000 Datalogger ............................................................ 4
4.1.2.2 NL115 or CFM100 Storage Module .................................. 5
4.1.2.3 CPEC200 Valve Module .................................................... 6
4.1.2.4 CSAT3A Sonic Anemometer Head .................................... 6
4.1.2.5 Barometer ........................................................................... 7
4.1.2.6 Carrying Cases ................................................................... 7
4.1.2.7 Enclosure Mounting Options .............................................. 7
4.1.3 Common Accessories .................................................................... 8
4.1.4 Support Software ........................................................................ 10
4.1.5 Replacement Parts ....................................................................... 11
4.2 Theory of Operation ........................................................................... 13
4.2.1 EC155 Gas Analyzer ................................................................... 13
4.2.2 CSAT3A Sonic Anemometer Head ............................................ 14
4.2.3 Valve Module .............................................................................. 14
4.2.4 Pump Module .............................................................................. 16
4.3 Specifications ..................................................................................... 17
5. Installation ................................................................. 17
5.1 Mounting ............................................................................................ 18
5.1.1 Support Structure ........................................................................ 18
5.1.2 Mount Enclosures ....................................................................... 18
5.1.3 Install EC Sensors ....................................................................... 19
5.2 Plumbing ............................................................................................ 21
5.2.1 Pump Module .............................................................................. 21
5.2.2 Zero/Span .................................................................................... 22
5.3 Wiring ................................................................................................ 23
5.3.1 Ground Connections ................................................................... 23
5.3.2 EC Sensor Cables ........................................................................ 24
5.3.3 Pump Module Cable.................................................................... 27
5.3.4 Apply Power ............................................................................... 27
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Table of Contents
5.4 Configure the Program ...................................................................... 28
5.4.1 System Configuration Variables ................................................. 28
5.4.2 Compile Switches ....................................................................... 32
5.5 Verify Proper Operation .................................................................... 32
6. Zero and Span ........................................................... 33
6.1 Introduction ....................................................................................... 33
6.2 Automatic Zero and Span .................................................................. 34
6.3 Manual Zero and Span ....................................................................... 35
6.3.1 Manually starting the zero/span sequence .................................. 35
6.3.1.1 Temperature Control ........................................................ 35
6.3.1.2 Starting the sequence ....................................................... 36
6.3.1.3 Stopping the sequence ..................................................... 36
6.3.2 Full Manual Control of Zero and Span ....................................... 37
6.3.2.1 Getting Ready .................................................................. 37
6.3.2.2 Checking and Setting the Zero ........................................ 37
6.3.2.3 Checking and Setting the CO2 Span ................................ 38
6.3.2.4 Checking and Setting the H2O Span ................................ 38
6.3.2.5 Returning to Normal EC Mode ........................................ 39
7. Maintenance and Troubleshooting .......................... 39
7.1 Enclosure Desiccant .......................................................................... 40
7.2 EC155 Intake Filter ........................................................................... 40
7.3 EC155 Windows ................................................................................ 40
7.4 EC155 Chemical Bottles ................................................................... 41
8. Repair ......................................................................... 41
Appendices
CPEC200 Diagnostics ............................................. A-1
A.
A.1 Overview ......................................................................................... A-1
A.2 Status Text Variables ....................................................................... A-1
A.3 Status Boolean Variables ................................................................. A-6
A.4 CPEC200 Diagnostic Words ........................................................... A-8
B. Public Variables ...................................................... B-1
C. Output Variables ..................................................... C-1
D. Control Bits.............................................................. D-1
E. Using Swagelok® Fittings ....................................... E-1
E.1 Assembly .......................................................................................... E-1
E.2 Common Replacement Parts ............................................................ E-2
F. Installing the AC/DC Power Adapter Kit ............... F-1
ii
Table of Contents
G. CPEC200 Scrub Module Installation, Operation
and Maintenance .................................................. G-1
G.1 Theory of Operation ........................................................................ G-1
G.2 Scrub Module Specifications .......................................................... G-2
G.3 Installation ....................................................................................... G-2
G.4 Maintenance .................................................................................... G-3
H. CPEC200 Pump Replacement ................................ H-1
H.1 Introduction ..................................................................................... H-1
H.2 Removal .......................................................................................... H-1
H.3 Installation ....................................................................................... H-4
Figures
4-1. EC155 closed-path CO2/H2O gas analyzer ......................................... 2
4-2. EC100 electronics module ................................................................... 3
4-3. CPEC200 system enclosure ................................................................. 3
4-4. CPEC200 pump module ....................................................................... 4
4-5. CR3000 datalogger ............................................................................... 5
4-6. NL115 (left) and CFM100 (right) ........................................................ 5
4-7. CFMC2G 2GB CompactFlash® memory card .................................... 5
4-8. CPEC200 valve module ....................................................................... 6
4-9. CSAT3A sonic anemometer head ........................................................ 7
4-10. CPEC200 scrub module ....................................................................... 9
4-11. 17752 USB memory card reader/writer ............................................. 10
4-12. Intake filter of EC155 ......................................................................... 11
4-13. Single desiccant pack ......................................................................... 11
4-14. Humidity indicator card ..................................................................... 12
4-15. Diaphragm pump used in CPEC200 .................................................. 12
4-16. EC155 gas analyzer ............................................................................ 13
4-17. CSAT3A sonic anemometer head ...................................................... 14
5-1. CPEC200 enclosure, pump module, and EC100 mounted to legs
of CM110-series tripod ................................................................... 19
5-2. CM210 mounting bracket on a tripod mast ........................................ 20
5-3. Mounting of EC155 and CSAT3A ..................................................... 20
5-4. Plumbing connections ........................................................................ 21
5-5. Connecting pump tube from EC155 analyzer to pump module ......... 22
5-6. Enclosure and tripod grounded to a copper-clad grounding rod ........ 24
5-7. EC155 electrical connections (mounting hardware not shown) ......... 24
5-8. Wiring of power and communications ............................................... 25
5-9. Wiring to EC100 electronics .............................................................. 26
5-10. Wiring to CPEC200 enclosure ........................................................... 26
E-1. Swagelok® insert .............................................................................. E-3
E-2. Front and back Swagelok® ferrules .................................................. E-3
E-3. Swagelok® plug ................................................................................ E-4
E-4. Swagelok® cap ................................................................................. E-4
F-1. Peripheral mounting kit installed in CPEC200 enclosure ................ F-1
F-2. Power supply in mounting bracket ................................................... F-2
F-3. Secured power supply in mounting bracket ..................................... F-2
F-4. Connections for the power supply in CPEC200 enclosure ............... F-3
F-5. Powered supply in CPEC200 enclosure ........................................... F-3
G-1. CPEC200 scrub module .................................................................. G-1
G-2. Scrub module interior ...................................................................... G-3
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Table of Contents
Tables
G-3. Interior of CPEC200 scrub module with tubing and cover
removed ....................................................................................... G-4
G-4. Empty bottle showing the top (on the right with spring) and
bottom (left) caps ......................................................................... G-5
H-1. Four screws holding filter assembly inside CPEC200 pump
module enclosure ......................................................................... H-1
H-2. Upright filter unit in enclosure ........................................................ H-2
H-3. Location of #4 screws of pump assembly ........................................ H-2
H-4. Exposed CPEC200 pump assembly ................................................ H-3
H-5. Location of pump connector in CPEC200 pump electronics ........... H-3
H-6. Self-tapping screws attaching pump to metal box ........................... H-4
H-7. Location of cuts to remove pump assembly from tubing ................ H-4
H-8. Inlet and outlet tubing reconnected to pump ................................... H-5
H-9. Pump side with inlet and outlet tubing connected ........................... H-5
H-10. Proper positioning of CPEC200 in shell cover ................................ H-6
5-1. SDM Wiring ...................................................................................... 25
6-1. Automatic Zero/Span Sequence ........................................................ 35
A-1. Summary CPEC200 diagnostic flags encoded in diag_cpec ........... A-9
B-1. CPEC200 public variables ............................................................... B-1
C-1. Values stored in table ts_data .......................................................... C-1
C-2. Values stored in table flux ............................................................... C-3
C-3. Values stored in table zero_ span .................................................... C-6
C-4. Values stored in table message_log ................................................. C-9
C-5. Values stored in table config_history ............................................ C-10
D-1. CPEC200 temperature control bits encoded in ControlBits ............ D-1
E-1. Available plastic tubing sizes, construction, and usage
guidelines ...................................................................................... E-2
E-2. Dimensions and part numbers for Swagelok® inserts ....................... E-3
E-3. Dimensions and part numbers for Swagelok® ferrules ..................... E-3
E-4. Dimensions and part numbers for Swagelok® plugs ........................ E-4
E-5. Dimensions and part numbers for Swagelok® caps .......................... E-4
iv
NOTE
CPEC200 Closed-Path Eddy-Covariance
System
1. Introduction
The CPEC200 is a closed-path, eddy-covariance (EC) flux system used for
long-term monitoring of atmosphere–biosphere exchanges of carbon dioxide,
water vapor, heat, and momentum. This complete, turn-key system includes a
closed-path gas analyzer (EC155), a sonic anemometer head (CSAT3A),
datalogger (CR3000), sample pump, and optional valve module for automated
zero and span.
Before using the CPEC200, please study:
• Section 2, Cautionary Statements
• Section 3, Initial Inspection
• Section 5, Installation
Operational instructions critical to the preservation of the system are found
throughout this manual. Before using the CPEC200, please study the entire
manual. Further information pertaining to the CPEC200 can be found in the
Campbell Scientific publications EC155 CO
Analyzer Manual, available at www.campbellsci.com.
and H2O Closed-Path Gas
2
Other manuals that may be helpful include:
• CR3000 Micrologger Operator’s Manual
• CFM100 CompactFlash® Module Instruction Manual
• NL115 Ethernet and CompactFlash® Module Instruction Manual
• Application Note 3SM-F, PC/CF Card Information
• LoggerNet Instruction Manual
• ENC10/12, ENC12/14, ENC14/16, ENC16/18 Instruction Manual
• CM106 Tripod Instruction Manual
• Tripod Installation Manual Models CM110, CM115, CM120
• CSAT3 Three Dimensional Sonic Anemometer Manual
This user manual applies specifically to version 2.0 of the
CPEC200 CRBasic program.
2. Cautionary Statements
• WARNING:
o Do not connect or disconnect the EC155 gas analyzer head or the
CSAT3A sonic anemometer head from the EC100 electronics
while the EC100 is powered. Doing so can result in
unpredictable performance of the system or damage to the
instrument head.
o Grounding electrical components in the measurement system is
critical. Proper earth (chassis) grounding will ensure maximum
electrostatic discharge (ESD) protection and higher measurement
accuracy.
o Use care when connecting and disconnecting tube fittings to
avoid introducing dust or other contaminants.
1
CPEC200 Closed-Path Eddy-Covariance System
3. Initial Inspection
Upon receipt of the CPEC200, inspect the packaging and contents for damage.
File damage claims with the shipping company.
Model numbers are found on each product. On cables, the model number is
usually found at the connection end of the cable. Check this information
against the enclosed shipping documents to verify the expected products and
the correct lengths of cable are included.
4. Overview
The CPEC200 is a closed-path EC flux system used for long-term monitoring
of atmosphere–biosphere exchanges of carbon dioxide, water vapor, heat, and
momentum.
4.1 System Components
o Do not overtighten the tube fittings. Consult Appendix E, Using
Swagelok
o The CPEC200 power source should be designed thoughtfully to
ensure uninterrupted power. If needed, contact a Campbell
Scientific applications engineer for assistance.
o Retain all spare caps and plugs as these are required when
shipping or storing the CPEC200 system.
®
Fittings, for information on proper connection.
The CPEC200 consists of several components, some of which are optional.
Some additional accessories are required to complete a fully functioning
CPEC200 system and are described and illustrated in the sections that follow.
4.1.1 Standard Components
Standard with the CPEC200 are the CPEC200 system enclosure, EC155 gas
analyzer, EC100 electronics, and CPEC200 pump module.
4.1.1.1 EC155 Gas Analyzer
The EC155 is a closed-path, infrared CO
integrated electronics (EC100 electronics) with the CSAT3A sonic
anemometer head. For detailed information and specifications, see the EC155
manual at www.campbellsci.com. The EC155, as shown in FIGURE 4-1, is an
included part of the CPEC200 system.
FIGURE 4-1. EC155 closed-path CO2/H2O gas analyzer
O gas analyzer. It shares
2/H2
2
4.1.1.2 EC100 Electronics
The EC100 electronics module (FIGURE 4-2) controls the EC155 and
CSAT3A. It is housed in its own enclosure and must be mounted within 3 m
of the sensors.
CPEC200 Closed-Path Eddy-Covariance System
FIGURE 4-2. EC100 electronics module
4.1.1.3 CPEC200 Enclosure
The CPEC200 enclosure (FIGURE 4-3) houses the CR3000 datalogger, control
electronics, the optional valve module, and communications and power
terminals. Several options for mounting to a tower, tripod, or large diameter
pole can be specified when ordering the system.
FIGURE 4-3. CPEC200 system enclosure
3
CPEC200 Closed-Path Eddy-Covariance System
4.1.1.4 CPEC200 Pump Module
The pump module (FIGURE 4-4) uses a small, low-power diaphragm pump to
draw air through the EC155 sample cell. The pumping speed is automatically
controlled to maintain the volumetric flow at the setpoint (3 to 7 LPM). The
pump module is temperature controlled to keep the pump in its operating
temperature range of 0°C to 55°C. The pump module includes a large-capacity
filter to protect the pump from contamination and dampen pressure fluctuations
in the sample cell that are caused by the pump.
FIGURE 4-4. CPEC200 pump module
4.1.2 Optional Components
4.1.2.1 CR3000 Datalogger
The CR3000 datalogger (FIGURE 4-5) is housed in the CPEC200 enclosure.
The CR3000 executes and stores measurements from all sensors. It calculates
online flux measurements, and stores both raw and processed data. Although
the CR3000 is a required component, the CPEC200 can be purchased without
the CR3000. However, the user must supply a CR3000 with the low-profile
base option.
4
FIGURE 4-5. CR3000 datalogger
4.1.2.2 NL115 or CFM100 Storage Module
The datalogger saves data onto a CompactFlash® (CF) memory card (FIGURE
4-7) via an optional NL115 or CFM100 card module (FIGURE 4-6). Either
module will provide data storage. The NL115 has the added capabilities that
are available with the Ethernet interface.
CPEC200 Closed-Path Eddy-Covariance System
FIGURE 4-6. NL115 (left) and CFM100 (right)
The CPEC200 can be ordered with either of the storage modules factory
installed. If the CPEC200 is ordered without a storage module, the user must
provide one. The CF card (FIGURE 4-7) can be ordered separately from
www.campbellsci.com. For details, see the CFM100 CompactFlash® Module
Instruction Manual or the NL115 Ethernet and CompactFlash® Module
Instruction Manual, and the Application Note 3SM-F, PC/CF Card
Information. All manuals are available at www.campbellsci.com.
FIGURE 4-7. CFMC2G 2GB CompactFlash® memory card
5
CPEC200 Closed-Path Eddy-Covariance System
NOTE
4.1.2.3 CPEC200 Valve Module
The optional CPEC200 valve module (FIGURE 4-8) is housed in the CPEC200
enclosure and is used to automate zero and CO
perform a field zero and field CO
span requires a dewpoint generator and cannot be automated because the
dewpoint generator is a laboratory instrument. Therefore, H
performed manually.
The CPEC200 valve module is available in two versions, one with three valves
(pn 27559) and another with six valves (pn 26578). The valve module is
normally ordered as a factory-installed option of the CPEC200, but the module
can also be ordered separately and installed by the user.
span checks, and automatically
2
span on a user-defined interval. Field H2O
2
O spans must be
2
FIGURE 4-8. CPEC200 valve module
4.1.2.4 CSAT3A Sonic Anemometer Head
The CSAT3A (FIGURE 4-9) is Campbell’s 3D sonic anemometer sensor head.
It shares integrated electronics (EC100 electronics) with the EC155 gas
analyzer. For detailed information and specifications, see the CSAT3 manual.
Campbell’s standalone sonic anemometer, the CSAT3, has its own
electronics box, whereas the CSAT3A shares the EC100
electronics with the EC155 gas analyzer. The measurement
specifications for the CSAT3 and CSAT3A are the same.
6
4.1.2.5 Barometer
CPEC200 Closed-Path Eddy-Covariance System
FIGURE 4-9. CSAT3A sonic anemometer head
4.1.2.6 Carrying Cases
The EC100 is always configured with an EC100 basic barometer. However, an
EC100 enhanced barometer is available as an option. The decision to upgrade
to the enhanced barometer is largely dependent on the specific site and
environmental constraints for a given site. In general, the enhanced barometer
provides overall greater accuracy, but may not be a necessary upgrade for
many applications.
Unlike open-path systems, the accuracy of the CPEC200 system is influenced
by the sample cell pressure. The EC155 sample cell pressure is measured by a
differential pressure sensor that measures the sample cell pressure relative to
barometric pressure (as measured by the EC100 barometer). The accuracy of
the sample cell pressure measurement is the sum of the accuracy of the
barometer in the EC100 and the differential pressure sensor in the EC155.
The measurement rate is likewise affected by both the sample cell pressure and
the specific barometric pressure of the barometer – either basic or enhanced.
The differential pressure sensor is always measured at 10 Hz, while the basic
barometer is measured at 10 Hz and the enhanced barometer is measured at 1
Hz.
For greater detail, see Section 4.3, Specifications, of this manual or consult a
Campbell Scientific applications engineer for specific sites and applications.
The EC155 and the CSAT3A may be ordered with optional carrying cases. If
the carrying cases are not ordered, the sensors are shipped in cardboard boxes.
4.1.2.7 Enclosure Mounting Options
The CPEC200 system enclosure and the CPEC200 pump module can be
configured with one of several mounting options. The CPEC system enclosure
is similar to the Campbell Scientific ENC16/18 enclosure, and the CPEC200
7
CPEC200 Closed-Path Eddy-Covariance System
NOTE
NOTE
pump module is similar to the ENC10/12 enclosure. The same mounting
options are available and outlined below:
• Triangular tower (UT10, UT20, or UT30)
• Tripod mast 3.8 cm (1.5 in) to 4.8cm (1.9 in) diameter
• Tripod leg (CM106 or CM106K tripod only)
• Large pole 10.2 cm (4.0 in) to 25.4 cm (10.0 in) diameter
• No mounting bracket
Consult the ENC10/12, ENC12/14, ENC14/16, ENC16/18 Instruction Manual,
available at www.campbellsci.com, for details on mounting bracket options.
4.1.3 Common Accessories
There are several items that may be required to complete the installation, but
are not included in the CPEC200. Some of the more common accessories are:
System Power Cable: Two power cables are required for the CPEC200; one
for the main CPEC200 system and one for the EC100 electronics.
The preferred power cable, CABLEPCBL-L, consists of a twisted red/black
pair of wire gauge (AWG) 16 within a rugged Santoprene™ jacket. It is cut to
the specified length and the end is finished for easy installation.
The “-L” designation after certain parts designates a cable or tube
length in feet. The length is specified by the user at the time of
order.
SDM Cable: An SDM communication cable is required to connect the EC100
to the CPEC200 system enclosure. The preferred SDM cable is CABLE4CBLL. This cable consists of four conductors with a shield and drain wire, and a
rugged Santoprene™ jacket. It is cut to the specified length and the end is
finished for easy installation.
Pump Tube: A tube must be used to connect the EC155 to the pump module.
If the EC155 is within 50 ft of the pump module, 3/8-in OD tubing, such as pn
26506, is recommended. For longer distances (up to 500 ft), a larger 1/2-in OD
tube (pn 25539) is recommended to minimize pressure drop in the tube. Preswaged pump tube assemblies, such as pn 26504-L, 3/8-in OD, or pn 26503-L,
1/2-in OD, are available for this purpose.
The fittings on the EC155 and the pump module are sized for 3/8in OD tubing. A reducer is required at each end for the larger
tubing size. These reducers are supplied as part of the pre-swaged
tube assembly.
Zero/span tubes: Tubes must be used to connect the EC155 and the zero and
span cylinders to the valve module. Bulk tubing may be cut to length and
CO
2
installed onsite using pn 15702 or its equivalent. This tubing has a 1/4-in OD
to fit the Swagelok
®
fittings on the EC155 and the valve module. The tubing
has an aluminum core to minimize diffusion through the tubing wall and a UVresistant, black, high-density polyethylene jacket. Maximum tubing length
available is a 500-ft roll.
8
CPEC200 Closed-Path Eddy-Covariance System
Minimize the length of these tubes to reduce the amount of equilibration time
required after the zero or CO
span cylinder is selected. One long tube is
2
required to connect the valve module to the EC155, and two short tubes are
required to connect the zero and CO
span cylinders to the valve module. Pre-
2
swaged tube assemblies (pn 21823-L) are available for this purpose.
CPEC200 Scrub Module: The CPEC200 scrub module (pn 27423) provides
a source of zero air and is used for zeroing the EC155. It consists of a pump
and a three-stage molecular sieve and connects to the CPEC200 system
enclosure. The scrub module (shown in FIGURE 4-10) eliminates the need for
a cylinder of zero air. A cylinder of known CO
is still required. The module
2
reduces the need for one of the two cylinders for zero/span and is useful in
locations where transporting and replacing cylinders is inconvenient.
Additional information regarding installation and maintenance of the CPEC200
scrub module can be found in Appendix G, CPEC200 Scrub Module
Installation, Operation and Maintenance.
FIGURE 4-10. CPEC200 scrub module
AC/DC Power Adapter Kit: An AC/DC adapter kit (pn 28549) can be
configured within the CPEC200 system enclosure with a peripheral mounting
kit (pn 16987). This configuration allows the CPEC200 to be powered from
AC mains power. See Appendix F, Installing the AC/DC Power Adapter Kit,
for more information.
CF Card: The CPEC200 stores data on a CompactFlash® memory card.
There are two types of CF cards available today: industrial grade and standard
or commercial grade. Industrial grade PC/CF cards are certified to a higher
standard in that they are designed to operate over a wider temperature range,
offer better vibration and shock resistance, and have faster read/write times
than their commercial counterparts. Campbell Scientific recommends the use
of industrial-grade cards, such as the CFMC2G or CFMC16G (FIGURE 4-7)
9
CPEC200 Closed-Path Eddy-Covariance System
available from Campbell Scientific. For more details about this card, see
Application Note 3SM-F, PC/CF Card Information, available from
www.campbellsci.com.
USB Memory Card Reader/Writer: The USB memory card reader/writer
(pn 17752) is shown in FIGURE 4-11. It is a single-slot, high-speed
reader/writer that allows a computer to read a memory card. When used with
Campbell Scientific equipment, the 17752 typically reads data stored on
CompactFlash® cards, but it can read many different types of memory cards.
FIGURE 4-11. 17752 USB memory card reader/writer
4.1.4 Support Software
There are several software products available for interfacing a PC to the
CPEC200’s datalogger.
PC200W: PC200W is a free, starter software package that provides basic
tools such as clock set, program download, monitor data, retrieve data, etc.
PC200W supports direct connections between PC and datalogger but has no
telecommunications or scheduled data-collection support.
PC400: PC400 is a mid-level software package that supports a variety of
telecommunication options, manual data collection, data display, and includes
a full-featured CRBasic program editor. PC400 does not support combined
communication options (for example, phone-to-RF), PakBus® routing, or
scheduled data collection.
LoggerNet: LoggerNet is a full-featured software package that supports
programming, communication, and data collection and display. LoggerNet
consists of a server application and several client applications integrated into a
single product. This package is recommended for applications that require
telecommunications support, scheduled data retrieval, or for large datalogger
networks.
LoggerLink Mobile Apps: The LoggerLink Mobile Apps allows an iOS or
Android device to communicate with an IP-enabled datalogger such as the
CR3000. The apps support field maintenance tasks such as viewing and
collecting data, setting the clock, and downloading programs.
10
4.1.5 Replacement Parts
Intake Filter: The EC155 intake filter (FIGURE 4-12) will become clogged
over time and must be replaced. The default replacement part is pn 26072. It is
a 2.5-cm (1.0-in) diameter, sintered stainless steel disk filter with a 20 µm pore
size encased in a molded Santoprene™ shell. An alternative 40 µm filter (pn
28698) is also available. Use a 40 µm filter if the default 20 µm filter clogs
long before the EC155 optical windows become dirty.
FIGURE 4-12. Intake filter of EC155
Sonic Wicks: A sonic wicks spares kit (pn 28902) is used to replace the wicks
on the CSAT3A. The kit includes three top wicks, three bottom wicks, an
installation tool, and adhesive.
CPEC200 Closed-Path Eddy-Covariance System
Silica Desiccant Bags: Silica desiccant bags (FIGURE 4-13) are used to
desiccate the CPEC200 system enclosure and should be periodically replaced.
A single four-unit silica desiccant bag is pn 4905. These can be purchased in
quantities of 20 as pn 6714.
FIGURE 4-13. Single desiccant pack
Humidity Indicator Card: The replacement humidity indicator card
(FIGURE 4-14) provides a visual reference of humidity level inside the
enclosure. A single replacement card is pn 28878.
11
CPEC200 Closed-Path Eddy-Covariance System
FIGURE 4-14. Humidity indicator card
EC155 Replacement Chemical Bottles: The EC155 has two small bottles
filled with chemicals to remove CO
sensor head. If replacement bottles are needed, two bottles are included with
pn 26511.
and water vapor from the inside of the
2
Diaphragm Pump: The pump module for the CPEC200 includes a small
double-head diaphragm pump with a brushless DC motor. The pump includes
a speed-control input and a tachometer to measure actual pumping speed. It is
mounted in an insulated, temperature-controlled box inside the CPEC200
system enclosure. If the pump fails, the replacement pump (FIGURE 4-15) is
available as pn 26402. The part includes the connector for easy installation.
See Appendix H, CPEC200 Pump Replacement, for instructions on replacing
the pump.
12
FIGURE 4-15. Diaphragm pump used in CPEC200
4.2 Theory of Operation
The CPEC200 is used for long-term monitoring of atmosphere–biosphere
exchanges of carbon dioxide, water vapor, heat, and momentum. This
complete, turn-key system includes a closed-path gas analyzer (EC155), a
sonic anemometer head (CSAT3A), datalogger (CR3000), sample pump, and
an optional valve module for automated zero and span.
4.2.1 EC155 Gas Analyzer
The EC155 (FIGURE 4-16) is Campbell Scientific’s closed-path, mid-infrared
absorption gas analyzer that measures molar mixing ratios of carbon dioxide
and water vapor. More information about the operation of the EC155 can be
found in the manual, EC155 CO
www.campbellsci.com.
CPEC200 Closed-Path Eddy-Covariance System
and H2O Closed-path Gas Analyzer at
2
FIGURE 4-16. EC155 gas analyzer
13
CPEC200 Closed-Path Eddy-Covariance System
4.2.2 CSAT3A Sonic Anemometer Head
The CSAT3A, as shown in FIGURE 4-17, is an ultrasonic anemometer sensor
head for measuring wind speed in three dimensions. It shares integrated
electronics, the EC100 electronics, with the EC155 gas analyzer. It is similar
to the sensor head for the CSAT3 sonic anemometer, with the primary
difference being that the CSAT3 can be used as a standalone anemometer
because it includes independent electronics. The CSAT3A uses three
nonorthogonal pairs of transducers to sense the wind velocity vector. Each pair
of transducers transmits and receives ultrasonic pulses to determine the time of
flight, which is directly related to the speed of sound and the wind speed along
the line between the pair of transducers. The CSAT3A transforms the results
into orthogonal wind components u
head.
The CSAT3A also determines the speed of sound for each transducer pair.
These measurements are averaged and converted to sonic virtual temperature
) based on the relationship between speed of sound and air temperature. For
(T
s
more detailed information and specifications, see the CSAT3 manual.
, uy, and uz, referenced to the anemometer
x
14
FIGURE 4-17. CSAT3A sonic anemometer head
4.2.3 Valve Module
The optional valve module, shown in FIGURE 4-8, is housed in the CPEC200
enclosure and is used to automate zero and CO
perform a zero and CO
Section 4.1.2.3, CPEC200 Valve Module, H
generator and cannot be automated.
The CPEC200 valve module is available in two versions, one with three valves
(pn 27559) and another with six valves (pn 26578). The valve module is
normally ordered as a factory-installed option, but can also be ordered
separately and installed by the user.
span checks, and automatically
2
span on a user-defined interval. As described in
2
O span requires a dewpoint
2
CPEC200 Closed-Path Eddy-Covariance System
For the three-valve version, the inputs are:
• Zero
• CO
• H
Span 1
2
O Span
2
For the six-valve version, the inputs are:
• Zero
• CO
• CO
• CO
• CO
• H
Span 1
2
Span 2
2
Span 3
2
Span 4
2
O Span
2
The CPEC200’s zero and CO
that they flow only when selected. This allows the zero and CO
span inlets are not bypass equipped, meaning
2
span tanks to
2
be continuously connected for automatic, unattended operation.
The H
O Span input is bypassed (vented to the atmosphere through the H2O
2
Span Bypass outlet) when it is not selected, so it permits flow all the time.
This allows a dewpoint generator to be connected directly to the H
O Span
2
inlet. The dewpoint generator’s internal pump can push flow into the valve
module even when the H
caused by pressurization inside the dewpoint generator. When the H
O Span valve is not selected, minimizing errors
2
O Span
2
valve is selected, the dewpoint generator pushes moist air through the valve
module to the EC155.
The CPEC200 pushes the zero/span flow backward through the EC155 sample
cell and exhausts it through the intake tube to the atmosphere. Flow through
the intake tube causes the sample-cell pressure to rise slightly above ambient
pressure. The CPEC200 infers the flow rate from this pressure rise. The
EC155 has a differential pressure sensor to measure this pressure rise directly,
but its accuracy is affected by a small offset drift. The accuracy of this
differential pressure measurement can be improved by stopping all flow
through the EC155, allowing the pressure in the sample cell to equilibrate with
ambient pressure, and measuring the differential pressure offset. This offset is
then subtracted from subsequent measurements used to control the flow.
Because the pressure sensor offset can change over time, this offset is
measured at the beginning of every zero/span cycle. This step requires at least
10 seconds to complete; 5 seconds for the pressure to equilibrate, and 5
seconds to average and store the differential pressure measurement.
Either of the CPEC200 valve modules have a proportional control valve to
actively control the flow of zero and span gas to the EC155. The CPEC200
program adjusts public variable valveControl between 0 (closed) and 1 (fully
open) as needed for the measured flow valve_flow to reach the desired flow, as
indicated by CAL_FLOW_SETPT. The default value for
CAL_FLOW_SETPT is 1.0 LPM. This flow is adequate for lower
measurement heights (allowing a shorter tube between the valve module and
the EC155), but setting a higher flow rate may be required with long zero/span
delivery tubes used on tall towers. The proportional valve is opened fully
during an H
O span operation to prevent pressurizing the dewpoint generator.
2
15
CPEC200 Closed-Path Eddy-Covariance System
The CPEC200 valve module includes a heater and a fan to keep the valves
within their operating range of 0°C to 60°C. The valve heater turns on/off at
2°C. The valve fan turns on at 50°C and stays on until the valve temperature
drops to 48°C. To conserve power, temperature control is active just prior to
and during the time when valves are in use. If the valves cannot be maintained
within the temperature range, the valves are disabled. The valve module
temperature control can be manually activated so that manual zero/span can be
performed by the station operator on site or remotely. If starting from the
minimum ambient temperature (–30°C), the valves may take as much as 15
min to warm up to the operating range of 0°C to 60°C.
4.2.4 Pump Module
The CPEC200 pump module pulls air through the system and exhausts it
through the Exhaust fitting on the bottom of the enclosure. It uses a small
double-head diaphragm pump with a brushless DC motor. This pump includes
a speed control input and a tachometer to measure the actual pumping speed. It
is mounted in an insulated, temperature-controlled box located inside the
weather-tight fiberglass enclosure. The pump module includes a large filter
cartridge to dampen the pressure fluctuations from the pump and to protect the
pump from particulates or debris.
If the pump fails, the replacement pump is available as pn 26402 (see Section
4.1.5, Replacement Parts). See Appendix H, CPEC200 Pump Replacement,
for instructions on replacing the pump. The filter cartridge in the pump module
is unlikely to clog over the lifetime of the CPEC200 system.
The following sections describe operating parameters of the pump.
Pump Speed: The pump tachometer is measured, converted to volumetric
flow rate, and reported in public variable pump_flow. The CPEC200 sets the
value of public variable pump_control to a value between 0 (off) and 1 (full
speed) to adjust the pump’s speed as needed to match pump_flow to the
setpoint flow PUMP_SETPT. PUMP_SETPT is a system configuration
variable (see Section 5.4.1, System Configuration Variables).
Pump Inlet Pressure: The measured inlet pressure of the pump is reported in
public variable pump_press. This pressure will normally be slightly lower (~1
kPa) than the EC155 sample cell pressure due to the pressure drop in the pump
tube.
Pump Temperature: The temperature of the pump module is reported in
public variable pump_tmpr. The operating range of the pump is 0°C to 55°C.
If the pump temperature is outside this range, the CPEC200 will disable the
pump. The pump module has a heater (drawing 8 W while operational) that
turns on if the pump temperature falls below 2°C. If the CPEC200 is started at
cold temperature, it may take up to 50 minutes to warm the pump module
(from –30°C to 0°C). When it reaches 2°C the heater will cycle on/off as
needed to maintain this temperature.
The pump module has a fan (drawing 0.7 W while operational) that turns on if
the pump temperature rises above 50°C. The fan will stay on until the pump
temperature falls below 45°C.
16
The outlet of the pump connects the Exhaust fitting on the bottom of the pump
module enclosure. This fitting has a screen to prevent insects or debris from
entering when the pump is off.
4.3 Specifications
System
Operating temperature: –30° to +50°C
Input voltage: 10.5 to 16.0 Vdc
Power: 12 W (typical), 35 W (max, at cold startup)
System enclosure
Dimensions: 52.1 x 44.5 x 29.7 cm (20.5 x 17.5 x 11.7 in)
Weight basic system: 11.6 kg (25.5 lb)
CR3000: 1.6 kg (3.7 lb)
CFM100/NL115: 0.2 kg (0.4 lb)
Three-valve module: 1.5 kg (3.3 lb)
Six-valve module: 1.9 kg (4.2 lb)
Pump module
Cable length: 3.0 m (10 ft)
Inlet connection: 3/8-in Swagelok
Pressure sensor range: 15 to 115 kPa
Pumping speed: 3 to 9 LPM (automatically controlled at the
Dimensions: 35.6 x 29.2 x 13.5 cm (14.0 x 11.5 x 5.3 in)
Weight w/ out mounting: 5.4 kg (11.8 lb)
CPEC200 Closed-Path Eddy-Covariance System
®
set-point, typically 7 LPM)
5. Installation
Valve module
Flow rate: 1 to 5 LPM (automatically controlled at the
set-point, typically 1 LPM)
Inlets
Three-valve module: Zero, CO
Six-valve module: Zero, CO
Outlets: Analyzer and H
Connections: 1/4-in Swagelok
span, and H2O span
2
spans 1 through 4, and H2O span
2
O bypass
2
®
Dimensions: 14.0 x 12.7 x 14.0 cm (5.5 x 5.0 x 5.5 in.)
Weight
Three-valve module: 1.5 kg (3.3 lb)
Six-valve module: 1.9 kg (4.2 lb)
EC155 and CSAT3A Specifications: see the user manual: EC155 CO
O Closed-path Gas Analyzer Manual and CSAT3 Three Dimensional Sonic
H
2
and
2
Anemometer Manual
The following tools are required to install the CPEC200 system in the field.
Additional tools may be required for a user-supplied tripod or tower.
• 9/16-in, open-end wrench
• 1/2-in, open-end wrench
• 11/16-in, open-end wrench
• Adjustable wrench
17
CPEC200 Closed-Path Eddy-Covariance System
NOTE
• Small, flat-tip screwdriver (included with EC100 and CPEC200)
• Large, flat-tip screwdriver (included with EC100)
• Sledgehammer (to drive grounding rod into the ground)
• 3/16-in hex-key wrench (included with CM250 leveling mount)
5.1 Mounting
5.1.1 Support Structure
The CPEC200 system has four major components that must be mounted to a
user-provided support structure. The support structure itself is not included in
the CPEC200 so that it can be tailored to specific needs, but several options are
available. Contact a Campbell Scientific applications engineer for more
information on site-specific mounting options.
EC sensors (EC155 and CSAT3A): Mounted on a horizontal round pipe of
3.33 cm (1.31 in) outer diameter, such as the CM20X crossarm.
EC100 electronics: Mounted within 3.0 m (10 ft) of the EC sensors. The
EC100 mounting bracket will accommodate a pipe at any orientation, with
outer diameter from 2.5 cm to 4.8 cm (1.0 in to 1.9 in).
CPEC200 enclosure: Mounted where it can be accessed easily to retrieve data
from the CF cards on the datalogger. The CPEC200 enclosure is similar to the
ENC16/18, with the same mounting options (tower, tripod, leg, or pole).
CPEC200 pump module: Mounted within 3.0 m (10 ft) of the CPEC200
enclosure. The pump module enclosure is similar to the ENC10/12, with the
same mounting options (tower, tripod, leg, or pole).
Consult the ENC10/12, ENC12/14, ENC14/16, ENC16/18 Instruction Manual,
available at www.campbellsci.com, for details on mounting bracket options.
The following sections describe a typical application using a CM110 tripod and
CM202 crossarm. The CPEC200 enclosure and the CPEC200 pump module
are shown with the leg-mount options. The CM110 tripod and the leg
mounting options, shown in FIGURE 5-1, are ideal for a low EC measurement
height to minimize wind disturbance.
5.1.2 Mount Enclosures
Mount the EC100 electronics within 3.0 m (10 ft) of the EC sensors (this
measurement corresponds to the length of the cables on the EC155 and the
CSAT3A).
The EC100 should be mounted vertically to prevent water ingress
from precipitation.
The mounting bracket will accommodate a horizontal, vertical, or angled pipe
from 2.5 cm to 4.8 cm (1.0 in to 1.9 in) diameter. See the EC155 user manual
for details on configuring the EC100 mounting bracket. The EC100 electronics
are shown mounted on one leg of a CM110 tripod in FIGURE 5-1.
18
Mount the CPEC200 enclosure and the CPEC200 pump module within 3.0 m
(10 ft) distance. The enclosure and pump module are shown mounted back-to-
CPEC200 Closed-Path Eddy-Covariance System
CPEC200 Enclosure
Pump Module
EC100
Electronics
back on the leg of a CM110 tripod in FIGURE 5-1, but they may also be
mounted on a vertical pipe, triangular tower, or large-diameter pole, depending
on the site requirements and the mounting options ordered.
FIGURE 5-1. CPEC200 enclosure, pump module, and EC100 mounted
to legs of CM110-series tripod
For the EC100 and the system enclosure, open the sealed bag containing the
desiccant packs and humidity card. Place two of the desiccant packs and the
humidity indicator card in the mesh pocket in the enclosure door. Reseal the
remaining two desiccant packs in the bag to use later.
5.1.3 Install EC Sensors
Install a horizontal mounting crossarm at the height desired for the EC
measurement. This crossarm must be within ±15 degrees of horizontal to level
the sonic anemometer. Point the crossarm into the predominant wind direction
to minimize wind disturbance caused by wind flowing past the mounting
structure and EC sensors. The outer diameter of the crossarm should be 3.3 cm
(1.3 in). The CM202 crossarm is shown in FIGURE 5-2.
19
CPEC200 Closed-Path Eddy-Covariance System
CM202 Crossarm
CM210 Crossarm-to-
Leveling
Bubble
CSAT3A Sonic
Anemometer Head
EC155
Gas Analyzer
CM20X
Crossarm
CM250 Leveling
Mount
Mounting
Platform
Pole Bracket
FIGURE 5-2. CM210 mounting bracket on a tripod mast
The EC155 gas analyzer and CSAT3A sonic anemometer head are mounted on
the end of the crossarm using the CM250 leveling mount and the CPEC200
mounting platform, as shown in FIGURE 5-3. Adjust the tilt of the mounting
platform to level the CSAT3A. For more details see instructions in the EC155
and H2O Closed-path Gas Analyzer manual.
CO
2
20
FIGURE 5-3. Mounting of EC155 and CSAT3A
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