Campbell Scientific EC155 User Manual

INSTRUCTION MANUAL

EC155 CO2 and H2O Closed-Path

Copyright © 2010- 2014

Campbell Scientific, Inc.

Gas Analyzer

Revision: 6/14

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 [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 "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 [e-mail] or faxed to
[phone]. Campbell Scientific is unable to 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.

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

5. Specifications ............................................................. 3

5.1 Measurements ...................................................................................... 3

5.2 Output Signals ...................................................................................... 5

5.3 Physical Description ............................................................................. 6

5.4 Power Requirements ............................................................................ 8

6. Installation ................................................................... 8

6.1 Mounting .............................................................................................. 8

6.2 Plumbing ............................................................................................ 11

6.2.1 Flow ............................................................................................ 11

6.2.2 Pressure ....................................................................................... 11

6.2.3 Filtration ...................................................................................... 12

6.2.4 Plumbing Connections ................................................................ 12

6.2.4.1 Sample Intake ................................................................... 13

6.2.4.2 Pump ................................................................................ 13

6.2.4.3 Zero and Span................................................................... 13

6.3 Wiring and Connections ..................................................................... 14

7. Settings ...................................................................... 17

7.1 Factory Defaults ................................................................................. 17

7.2 Details ................................................................................................ 18

7.2.1 SDM Address .............................................................................. 18

7.2.2 Bandwidth ................................................................................... 18

7.2.3 Unprompted Output .................................................................... 18

7.2.4 Unprompted Output Rate ............................................................ 18

7.2.5 RS-485 Baud Rate ....................................................................... 19

7.2.6 Analog Output ............................................................................. 19

7.2.7 ECMon Update Rate ................................................................... 19

7.2.8 Temperature Sensor .................................................................... 19

7.2.9 Fixed Temperature Value ............................................................ 19

7.2.10 Pressure Sensor ........................................................................... 19

7.2.10.1 Pressure Gain.................................................................... 20

7.2.10.2 Pressure Offset ................................................................. 20

7.2.10.3 Fixed Pressure Value ........................................................ 20

7.2.11 Differential Pressure ......................................................... 20

7.3 ECMon ............................................................................................... 20

i

Table of Contents

7.4 Device Configuration Utility ............................................................. 23

8. EC100 Outputs .......................................................... 23

8.1 SDM Output ...................................................................................... 23

8.2 USB or RS-485 Output ...................................................................... 24

8.3 Analog Outputs .................................................................................. 26

9. Maintenance .............................................................. 26

9.1 Routine Maintenance ......................................................................... 26

9.2 Intake Filter Replacement .................................................................. 27

9.3 Cleaning Analyzer Windows ............................................................. 28

9.4 Zero and Span .................................................................................... 31

9.5 Replacing the EC155 Desiccant/CO2 Scrubber Bottles ..................... 34

9.6 Factory Recalibration ........................................................................ 36

10. Datalogger Programming with CRBasic ................. 37

10.1 EC100() Instruction ........................................................................... 37

10.2 EC100Configure() Instruction ........................................................... 40

10.2.1 ConfigCmd 11 Zero-and-Span Control ...................................... 42

10.2.2 ConfigCmd 18 Heater Voltage ................................................... 42

10.3 Example CRBasic Program ............................................................... 43

11. Theory of Operation .................................................. 44

Appendices

Filter Bandwidth and Time Delay ........................... A-1

A.

B. Useful Equations ..................................................... B-1

C. EC155 Sample Cell and Intake Maintenance ........ C-1

C.1 Cleaning Sample Cell ...................................................................... C-1

C.2 Cleaning Intake Tube ...................................................................... C-1

Dust Blowout ........................................................................... C-1

C.2.1

C.2.2 Solvent Flush ............................................................................ C-2

D. Material Safety Data Sheets (MSDS) ..................... D-1

D.1 Magnesium Perchlorate MSDS ....................................................... D-1

D.2 Decarbite MSDS .............................................................................. D-2

E. EC155 Packing Information .................................... E-1

Figures

5-1. Dimensions of EC155 analyzer head with optional heated intake ....... 7

5-2. Dimensions of EC155 analyzer head without optional heated intake . 7
6-1. Exploded view of mounting the EC155 gas analyzer and the

CSAT3A sonic head ........................................................................ 9

ii

Table of Contents

6-2. EC100 enclosure mounting bracket mounted on a vertical mast

(left) and a tripod leg (right) ........................................................... 10

6-3. Exploded view of mounting the EC100 enclosure ............................. 11

6-4. End views of the analyzer showing the sample intake (optional

heated intake not shown), pump outlet, and zero-and-span

intake .............................................................................................. 13

6-5. EC100 electronics front panel. The picture on the left shows the

panel as it is shipped from the factory (enhanced barometer
shown). The picture on the right shows the panel after the user
has done all the wiring and made all connections (basic

barometer used). ............................................................................. 14

6-6. Bottom of EC100 enclosure ............................................................... 15

7-1. The Main window of ECMon ............................................................ 21

7-2. The Setup window in ECMon ............................................................ 22

7-3. The ECMon Status window ............................................................... 22

8-1. An example of USB data output in terminal mode ............................ 25

9-1. The underside of the optional heated intake ....................................... 28

9-2. The EC155 analyzer with the top shell open ...................................... 29

9-3. By loosening the thumbscrews above the sample cell, the latches

may be spun from position A to position B, thus freeing the

struts of the analyzer. ...................................................................... 29

9-4. The EC155 analyzer and sample cell with shell top open .................. 30

9-5. Analyzer removed from sample cell and shell ................................... 30

9-6. ECMon Zero/Span window ................................................................ 34

9-7. Replacing the source housing desiccant/scrubber bottle .................... 35

9-8. Replacing the detector housing desiccant/scrubber bottle .................. 36

A-1. Frequency and amplitude response of the EC100 filter at various

bandwidths ................................................................................... A-2

A-2. Frequency response comparison of the EC100 10-Hz bandwidth

and a 50-msec moving average .................................................... A-3

Tables

6-1. EC100 SDM output to a Campbell Scientific CR1000, CR3000,

or CR5000 Datalogger .................................................................... 16

7-1. Factory Default Settings ..................................................................... 17

8-1. USB and RS-485 Output Elements .................................................... 25

8-2. Multipliers and Offsets for Analog Outputs ....................................... 26

10-1. Output Modes for EC100 Instruction ................................................. 38

10-2. Bits in the Sonic Diagnostic Flag ....................................................... 38

10-3. Bits in the Gas Diagnostic Flag .......................................................... 39

10-4. ConfigCmd Values for Setting and Retrieving Settings ..................... 41

A-1. Filter Time Delays for Various Bandwidths ................................... A-3

iii

Table of Contents

iv

EC155 CO2 and H2O Closed-Path Gas
Analyzer

1. Introduction

The EC155 is an in-situ, closed-path, mid-infrared absorption gas analyzer that
measures molar mixing ratios of carbon dioxide and water vapor, along with
sample cell temperature and pressure. The EC155 may be used in conjunction
with the CSAT3 sonic anemometer, which measures orthogonal wind
components.

Before using the EC155, please study

• Section 2, Cautionary Statements

• Section 3, Initial Inspection

• Section 6, Installation

More details are available in the remaining sections.

2. Cautionary Statements

• DANGER:

o The scrubber bottles (see Section 9.5, Replacing the EC155

Desiccant/CO

agents sodium hydroxide (caustic soda, NaOH) and anhydrous
magnesium perchlorate (Mg(ClO

• WARNING:

o Do not carry the EC155 or CSAT3A by the arms or carry the

EC155 by the strut between the arms. Always hold them by the
block, where the upper and lower arms connect.

o Handle the EC155 carefully. The optical source may be damaged

by rough handling, especially while the analyzer is powered.

o Over-tightening bolts will damage or deform the mounting

hardware.

Scrubber Bottles) contain the strong oxidizing

2

).

4)2

 Avoid direct contact with the chemicals.
 Ensure your work area is well ventilated and free of

reactive compounds, including liquid water.

 Store used chemical bottles in a sealed container until

disposal.

 Dispose of chemicals and bottles properly.
 Materials Safety Data Sheets (MSDS) are provided in

Appendix D. MSDS are updated periodically by
chemical manufacturers. Obtain current MSDS at

www.campbellsci.com.

1

EC155 CO2 and H2O Closed-Path Gas Analyzer

• CAUTION:

o Grounding the EC100 measurement electronics is critical. Proper

grounding to earth (chassis) will ensure maximum ESD
(electrostatic discharge) protection and improve measurement
accuracy.

o Do not connect or disconnect the gas analyzer or sonic connectors

while the EC100 is powered.

o The SDM, USB, and RS-485 output options include EC155

diagnostic data. Be aware that the absence of diagnostic data in
the analog output option could make troubleshooting difficult and
may lead to the user not being aware of potential problems with
the instrumentation (see Section 8, EC100 Outputs).

o Resting the analyzer on its side during the zero-and-span

procedure may result in measurement inaccuracy.

o When cleaning the gas-analyzer window, make sure the alcohol

and any residual water completely evaporate before proceeding
with the zero-and-span procedure (see Section 9.3, Cleaning
Analyzer Windows).

3. Initial Inspection

Upon receipt of your equipment, inspect the packaging and contents for
damage. File damage claims with the shipping company.

4. Overview

The EC155 is a closed-path, mid-infrared absorption analyzer that measures
molar mixing ratios of carbon dioxide and water vapor, along with sample cell
temperature and pressure. It has been designed specifically for eddy
covariance flux measurements and may be used in conjunction with the
CSAT3A 3D sonic anemometer head. The analyzer has a rugged, aerodynamic
design with low power requirements, making it suitable for field applications.

The EC155 gas analyzer connects directly to the EC100 electronics, which
computes real-time CO
sample cell of the analyzer. A CSAT3A sonic anemometer head may also be
connected to the EC100.

The EC155 has been designed specifically to address issues of aerodynamics,
power consumption, performance during precipitation events, ambient air
density fluctuations, temporal synchronicity, and system integration. Its unique
design enables it to operate with only 4.8 W power; it has minimal spatial
displacement from the sample volume of a CSAT3A sonic anemometer; the
EC100 electronics synchronize data from the EC155 and CSAT3A; and the
analyzer is easily integrated into the CPEC200 closed-path eddy covariance
system, a turn-key system containing data acquisition and control
instrumentation, a sample pump, and optional zero-and-span valve module.

and H2O molar mixing ratios of the air inside the

2

2

5. Specifications

5.1 Measurements

Features

• To compute carbon dioxide, water vapor, and sensible heat fluxes using

These measurements are required to compute carbon dioxide and water vapor
fluxes using the:

• Standard outputs:

EC155 CO2 and H2O Closed-Path Gas Analyzer

the eddy-covariance method, the EC155 measures:

o absolute carbon dioxide
o water vapor mixing ratios
o three-dimensional wind speed (requires CSAT3A)
o sonic air temperature (requires CSAT3A)
o sample-cell temperature
o barometric pressure

o CO

mixing ratio, H2O mixing ratio

2

o gas analyzer diagnostic flags
o cell temperature, cell pressure
o CO

signal strength, H2O signal strength

2

o differential pressure
o air temperature and air pressure are auxiliary sensor inputs

• Additional outputs:

o u

, uy, and uz orthogonal wind components

x

o sonic temperature (based on the measurement of c, the speed of

sound)

o sonic diagnostic flags

Compatibility: CR1000
CR3000
CR5000

Measurement

Rate: 100 Hz

2

Output bandwidth
Output rate

2

Operating temperature: -30

: 5, 10, 12.5, 20, or 25 Hz

: 10, 25 or 50 Hz

o

to 50oC

Gas analyzer

1

Measurement precision

density: 0.2 mg·m

CO

2

O density: 0.00350 g·m

H

2

-3

(0.15 µmol·mol-1)

-3

(0.006 mmol·mol-1)

3

EC155 CO2 and H2O Closed-Path Gas Analyzer

Factory calibrated range

: 0 to 1000 µmol·mol-1

CO

2

O: 0 mmol·mol

H

2

Analyzer temp: -30
Baro pressure: 70 to 106 kPa

performance

CO

2

Zero max drift
Gain Drift: ±0.1% of reading·°C
Sensitivity to H

O performance

H

2

Zero max drift
Gain Drift: ±0.3% of reading·°C
Sensitivity to CO

CSAT3A sonic measurement precision

: 1 mm·s-1

u

x

: 1 mm·s-1

u

y

: 0.5 mm·s-1

u

z

Sonic temperature: 0.025

-1

o

to 50oC

3

: ±0.55 mg·m-3·°C-1 (±0.3 μmol·mol·°C-1)

O: ±5.6 x 10-5 µmol CO2·mol-1 H2O (max)

2

3

: ±0.037 g·m-3·°C-1 (±0.05 mmol·mol-1·°C-1)

: ±0.05 mol H2O·mol-1 CO2 (maximum)

2

o

C

to 37oC dewpoint

4

-1

(maximum)

-1

(maximum)

5

CSAT3A sonic accuracy

Offset error

, uy: < ±8 cm·s-1

u

x

: < 4 cm·s-1

u

z

Gain error

Wind vector ±5° horizontal: < ±2% of reading
Wind vector ±10° horizontal: < ±3% of reading
Wind vector ±20° horizontal: < ±6% of reading

CSAT3A sonic reporting range

Full scale wind: ±65.553 m/s
Sonic temperature: -50° to +60°C

6

Sample cell sensors

Barometer

Basic barometer

Accuracy

-30 to 0°C: ±3.7 kPa at -30°C, falling linearly to ±1.5

0° to 50°C: ±1.5 kPa

Measurement rate: 10 Hz
Optional enhanced barometer:

Manufacturer: Vaisala
Model: PTB110
Accuracy

-30 to 0°C: ±0.15 kPa

Measurement rate: 1 Hz

Temperature sensor:

Manufacturer: BetaTherm
Model: 100K6A1A Thermistor
Accuracy: ±0.15

o

kPa at 0

o

C

C (-30o to 50oC)

4

1

noise rms, assumes:

o 25°C
o 85 kPa
o 19 mmol/mol H
o 326 mmol/mol CO
o 25 Hz bandwidth.

2

user selectable

3

-30° to 50°C

4

noise rms

5

assumes:

o -30° to +50°C
o wind speed <30 m·s
o azimuth angles between ±170°

6

refer to manufacturer’s product brochure or manual for details

5.2 Output Signals

Features

• EC100 electronics outputs data using:

O concentration

2

o CS SDM
o RS-485
o USB
o Analog out

EC155 CO2 and H2O Closed-Path Gas Analyzer

concentration

2

-1

Digital

1

SDM (Synchronous Device for Measurement)

Data type: FLOAT

RS-485

Data type: ASCII
Output Rate
Baud rate

2

: 5 to 50 Hz

2

: 1200 to 230400 bps

USB

Data type: ASCII

2

Output rate

Analog (two outputs for CO

: 10, 25 or 50 Hz

and H2O molar mixing ratios)

2

Voltage range: 0 mV to 5000 mV
Resolution: 76 µV (16 bit)
Update rate: 150 Hz

o

Accuracy (at 25

C): ±3 mV

mixing ratio equation: µmol/mol = 211.27 (V

CO

2

) – 56.34

out

Full scale range: -56 to 1000 µmol/mol

O mixing ratio equation: mmol/mol = 11.31 (V

H

2

) – 3.04

out

Full scale range: -3 to 53 mmol/mol

1

Synchronous Device for Measurement. A Campbell Scientific, Inc. proprietary serial interface

for datalogger to peripheral and sensor communication. See Section 8.1, SDM Output for details.

2

user selectable

5

EC155 CO2 and H2O Closed-Path Gas Analyzer

5.3 Physical Description

Sample cell volume: 5.9 cm3 (0.36 in3)

Sample cell length: 12.0 cm (4.72 in)

Sample cell diameter: 7.94 mm (0.313 in)

Spatial separation between
EC155 optional intake and
CSAT3A sample volume: 15.6 cm (6.1 in)

Length of tubing from tip
of optional heated intake
to sample cell: 58.4 cm (23 in)

Inside diameter of intake tubing: 2.67 mm (0.105 in)

Dimensions

Analyzer: 42.7 cm x 7.4 cm x 10.1 cm (16.8 in x 2.9
in x 4.0)
Length of optional intake: 38.1 cm (15.0 in)
EC100 electronics: 24.1 cm x 35.6 cm x 14 cm (9.5 in x 14 in
x 5.5 in)
Cable length: 3 m (9.8 ft) from analyzer to EC100
electronics

Weight

Analyzer: 3.9 kg (8.5 lbs)
Mounting hardware: 0.4 kg (0.9 lbs)
EC100 electronics and

enclosure: 3.2 kg (7 lbs)

Connections

Pump: 3/8 inch Swagelok
Zero/Span: 1/4 inch Swagelok
Sample Intake: 1/8 inch Swagelok or Optional Heated
Intake Assembly

6

EC155 CO2 and H2O Closed-Path Gas Analyzer

FIGURE 5-1. Dimensions of EC155 analyzer head with optional heated

intake

FIGURE 5-2. Dimensions of EC155 analyzer head without optional

heated intake

7

EC155 CO2 and H2O Closed-Path Gas Analyzer

WARNING

5.4 Power Requirements

Voltage supply: 10 to 16 Vdc

6. Installation

6.1 Mounting

Power at 25

Power at 25

Power at 25
mode (CSAT3A fully powered
and EC155 in stand-by): 3.0 W

Power for optional heated intake: set by user, 0 to 0.7 W.

The EC155 is supplied with mounting hardware to attach it to the end of a
horizontal pipe of 1.31 inch outer diameter, such as the CM202, CM204, or
CM206 crossarm (pn 1790x). The EC155 mounting hardware also
accommodates an optional CSAT3A sonic anemometer, placing it at the proper
position when the EC155 is configured with the optional heated intake
assembly. The following steps describe the normal mounting procedure with
the optional heated intake assembly and optional CSAT3A sonic head. Other
mounting arrangements are acceptable as long as the analyzer is upright. The
bottom of the analyzer has two #6-32 UNC-thread mounting holes for
applications that do not use the EC155 mounting platform.

o

C including CSAT3A: 4.8 W

o

C excluding CSAT3A: 4.0 W

o

C in power-down

Refer to FIGURE 6-1 throughout this section.

a. Mount a CM202, CM204, or CM206 crossarm (pn 1790X) to a tripod or

other vertical structure using a CM210 crossarm-to-pole bracket (pn

17767). The crossarm should be within ± 7 degrees of horizontal to allow
the CSAT3A sonic anemometer to be leveled.

Do not carry the EC155 by the intake or the CSAT3A by the
arms. Always hold the instruments by the body or base.

b. Mount the CM250 leveling mount (pn 26559) on the end of the crossarm.

Tighten the set screws on the leveling mount.

c. Bolt the mounting platform (pn 26570) to the CM250 leveling mount (pn

26559).

d. Place the EC155 gas analyzer on the mounting platform so the four rubber

feet fit into the platform holes, and tighten the captive screws located on
the bottom of the platform into the mounting holes on the bottom of the
analyzer.

e. If a CSAT3A is being used, mount it on the end of the mounting platform

using the captive CSAT3A mounting bolt.

8

EC155 CO2 and H2O Closed-Path Gas Analyzer

WARNING

WARNING

NOTE

CSAT3A Sonic

EC155 Gas

CM20X Crossarm

Mounting Platform

CM250 Leveling

f. Level the assembly by slightly loosening the bolt in the CM250 leveling

mount. Adjust the assembly until the leveling bubble on top of the
CSAT3A is in the bullseye. Retighten the bolt.

Over-tightening bolts will damage or deform the mounting
hardware.

Use caution when handling the EC155 gas analyzer. The
optical source may be damaged by rough handling,
especially when the EC155 is powered.

If the assembly is to be mounted on a high tower, it can be hoisted
using the handle on the front of the analyzer and the holes in the
mounting platform.

(pn 26570)

Mount (pn 26559)

Anemometer Head

Analyzer

(pn 1790X)

FIGURE 6-1. Exploded view of mounting the EC155 gas analyzer and

the CSAT3A sonic head

9

EC155 CO2 and H2O Closed-Path Gas Analyzer

NOTE

The CSAT3A sonic anemometer is an updated version of the
CSAT3, designed to work with the EC100 electronics. An
existing CSAT3 may be upgraded to a CSAT3A. Contact
Campbell Scientific for details.

g. Attach the EC100 electronic enclosure to the mast, tripod leg, or other part

of the mounting structure. To do this, attach the EC100 enclosure
mounting bracket (pn 26604) to the pipe by loosely tightening the u-bolts
around the pipe. The u-bolts are found in the mesh pocket inside the
EC100 enclosure. If the pipe does not run vertically up-and-down (e.g., if
you are attaching the enclosure to a leg of a tripod), rotate the bracket to
the side of the pipe. As the enclosure must hang up-right, angle
adjustments may need to be made by loosening the four nuts and rotating
the bracket plates relative to one another. If the necessary angle cannot be
reached in the given orientation, the four nuts may be removed and the top
plate indexed by 90 degrees to allow the bracket to travel in the other
direction (see FIGURE 6-2). Once adjusted, tighten all the nuts. Finally
attach the EC100 enclosure to the bracket by loosening the bolts on the
back of the enclosure, hanging the enclosure on the mounting bracket (it
should slide into place and be able to securely hang from the bracket), and
tightening the bolts (see FIGURE 6-3).

10

FIGURE 6-2. EC100 enclosure mounting bracket mounted on a vertical

mast (left) and a tripod leg (right)

EC155 CO2 and H2O Closed-Path Gas Analyzer

6.2 Plumbing

6.2.1 Flow

6.2.2 Pressure

FIGURE 6-3. Exploded view of mounting the EC100 enclosure

h. Remove the EC100 enclosure desiccant from the plastic bag and put it

back in the mesh pocket of the enclosure. Adhere the humidity indicator
card to the inside of the enclosure.

The EC155 has a small sample cell volume (5.9 cm3) to give good frequency
response at a relatively low flow rate. The sample cell residence time is 50 ms
for a nominal 7 LPM flow. The CPEC200 pump module is designed to provide
this flow for the EC155, but other user-supplied pumps may be used. There is
no specific limitation to the flow rate that may be used with the EC155, but the
sample cell pressure must be considered.

The EC155 is designed to be used near ambient pressure, but it will not be
damaged by operation under vacuum. The EC155 includes a differential
pressure sensor to measure the sample cell pressure relative to ambient
pressure, which has a range of ± 7 kPa. If the EC155 is operated less than
7 kPa from ambient pressure, the user must attach a separate, user-supplied
pressure sensor.

11