Campbell EC150 User manual

EC150 CO2and H2O Open-Path
Gas Analyzer
Revision: 6/13
Copyright © 2010-2013
Campbell Scientific, Inc.

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warranted by Campbell Scientific, Inc. (“Campbell”) to be free from defects in
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
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 .............................................................2
5.1 Measurements ......................................................................................2
5.2 Output Signals......................................................................................5
5.3 Physical Description.............................................................................5
5.4 Power Requirements During Power-up and Operation ........................6
6. Installation...................................................................6
6.1 Orientation ...........................................................................................6
6.2 Mounting..............................................................................................6
6.3 Wiring and Connections.....................................................................11
7. Settings......................................................................14
7.1 Factory Defaults.................................................................................14
7.2 Details ................................................................................................15
7.2.1 SDM Address..............................................................................15
7.2.2 Bandwidth...................................................................................15
7.2.3 Unprompted Output ....................................................................15
7.2.4 Unprompted Output Rate ............................................................15
7.2.5 RS-485 Baud Rate.......................................................................16
7.2.6 Analog Output.............................................................................16
7.2.7 ECMon Update Rate ...................................................................16
7.2.8 Temperature Sensor ....................................................................16
7.2.9 Fixed Temperature Value............................................................16
7.2.10 Pressure Sensor ...........................................................................16
7.2.10.1 Pressure Gain....................................................................17
7.2.10.2 Pressure Offset .................................................................17
7.2.10.3 Fixed Pressure Value........................................................17
7.2.11 Pressure Differential Enable .......................................................17
7.2.12 Heater Control.............................................................................17
7.3 ECMon...............................................................................................17
7.4 Device Configuration Utility..............................................................19
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Table of Contents
8. EC100 Outputs ..........................................................19
8.1 SDM Output ...................................................................................... 20
8.2 USB or RS-485 Output...................................................................... 20
8.3 Analog Outputs.................................................................................. 22
9. Maintenance ..............................................................23
9.1 Routine Site Maintenance.................................................................. 23
9.2 Gas Analyzer Wicks.......................................................................... 23
9.3 Analyzer Window Cleaning .............................................................. 24
9.4 Zero and Span.................................................................................... 25
9.5 Replacing the EC150 Desiccant/CO2Scrubber Bottles..................... 29
9.6 Factory Recalibration ........................................................................ 30
10. Datalogger Programming with CRBasic .................30
10.1 EC100() Instruction ........................................................................... 30
10.2 EC100Configure() Instruction........................................................... 33
10.2.1 ConfigCmd 11 Zero-and-Span Control ...................................... 35
10.2.2 ConfigCmd 18 Heater Voltage................................................... 35
10.3 Example CRBasic Program............................................................... 36
11. Theory of Operation..................................................37
Appendices
A. Filter Bandwidth and Time Delay...........................A-1
B. Useful Equations.....................................................B-1
C. Material Safety Data Sheets (MSDS) .....................C-1
C.1 Magnesium Perchlorate MSDS ....................................................... C-1
C.2 Decarbite MSDS.............................................................................. C-2
D. Packing Information................................................D-1
D.1 EC150-GH Packing Information ..................................................... D-1
D.2 EC150-SH Packing Information...................................................... D-2
Figures
5-1. Dimensions of EC150 analyzer head................................................... 6
6-1. Exploded view of mounting the CSAT3A sonic head and EC150
gas analyzer head ............................................................................. 8
6-2. Exploded view of mounting the EC150 gas analyzer head without
the CSAT3A .................................................................................... 8
6-3. EC100 enclosure mounting bracket mounted on a vertical mast
(left) and a tripod leg (right) .......................................................... 10
6-4. Exploded view of mounting the EC100 enclosure ............................ 10
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Table of Contents
6-5. EC100 electronics front panel. The one on the left shows
how the EC100 will look shipped from the factory (enhanced
barometer shown). The one on the right shows the panel
after the user has done all the wiring and made all connections
(basic barometer shown).................................................................11
6-6. Bottom of EC100 enclosure ...............................................................12
7-1. The Main screen in ECMon ...............................................................18
7-2. The Setup screen in ECMon...............................................................19
8-1. An example of USB data output in terminal mode ............................21
9-1. Proper location of the gas analyzer top wick (left) and bottom
wick (right) .....................................................................................24
9-2. The zero-and-span shroud mounted on the zero-and-span stand.
The top tube is the gas intake, the black cable is the temperature
thermistor, and the short bottom tube is the gas exhaust. ...............26
9-3. ECMon zero-and-span window..........................................................27
9-4. Replacing the desiccant/CO2scrubber bottles....................................29
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....................................................................13
7-1. Factory Default Settings.....................................................................14
8-1. USB and RS-485 Output Elements ....................................................21
8-2. Multipliers and Offsets for Analog Outputs.......................................22
9-1. Rain Wick Replacement Parts............................................................23
10-1. Output Modes for EC100 Instruction.................................................31
10-2. Bits in the Sonic Diagnostic Flag .......................................................31
10-3. Bits in the Gas Diagnostic Flag..........................................................32
10-4. ConfigCmd Values for Setting and Retrieving Settings.....................34
A-1. Filter Time Delays for Various Bandwidths ................................... A-3
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
EC150 CO2and H2O Open-Path Gas
Analyzer
1. Introduction
The EC150 is an in-situ, open-path, mid-infrared absorption gas analyzer that
provides measurements of absolute densities of carbon dioxide and water
vapor. The EC150 may be used in conjunction with the CSAT3A sonic
anemometer, which measures orthogonal wind components.
Before using the EC150, 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:
oThe scrubber bottles (see Section 9.5, Replacing Desiccant and
Scrubber Bottles) contain the strong oxidizing agents sodium
hydroxide (caustic soda, NaOH) and anhydrous magnesium
perchlorate (Mg(ClO4)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 C. MSDS are updated periodically by
chemical manufacturers. Obtain current MSDS at
www.campbellsci.com.
•WARNING:
oDo not carry the EC150 or CSAT3A by the arms or carry the
EC150 by the strut between the arms. Always hold them by the
block, where the upper and lower arms connect.
oHandle the EC150 carefully. The optical source may be damaged
by rough handling, especially while the analyzer is powered.
oOver-tightening bolts will damage or deform the mounting
hardware.
•CAUTION:
oGrounding the EC100 measurement electronics is critical. Proper
grounding to earth (chassis) will ensure maximum ESD
(electrostatic discharge) protection and improve measurement
accuracy.
oDo not connect or disconnect the gas analyzer or sonic connectors
while the EC100 is powered.
oThe SDM, USB, and RS-485 output options include EC150
diagnostic data. Be aware that the absence of diagnostic data in
1

EC150 CO2and H2O Open-Path Gas Analyzer
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).
oResting the analyzer on its side during the zero-and-span
procedure may result in measurement inaccuracy.
oWhen 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, Analyzer
Window Cleaning).
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 EC150 is an in-situ open path mid-infrared absorption analyzer that
measures absolute densities of carbon dioxide and water vapor. It has been
designed specifically for eddy covariance flux measurements and may be used
in conjunction with the CSAT3A 3D sonic anemometer sensor head. The
analyzer has a rugged, aerodynamic design with low power requirements,
making it suitable for field applications.
The EC150 gas analyzer head, along with a temperature probe and optional
external barometer, connect directly to the EC100 electronics. After receiving
inputs from these sensors, the EC100 computes CO2and H2O absolute
densities. A CSAT3A sonic anemometer head may also be connected to the
EC100. The EC100 synchronizes data from the EC150 and the CSAT3A,
essential for valid flux measurements using the eddy covariance method.
The EC150 has been designed specifically to address issues of aerodynamics,
power consumption, spatial displacement, and temporal synchronicity. Its
unique design contains no obstructions surrounding the sample volume; it
operates with 5 W of power at room temperature; it has minimal spatial
displacement from the sample volume of a CSAT3A sonic anemometer head;
and the EC100 synchronously samples data from the EC150 and CSAT3A.
5. Specifications
5.1 Measurements
Features
•To compute carbon dioxide and water vapor fluxes using the eddy-
covariance method, the EC150 measures:
oabsolute carbon dioxide
owater vapor densities
othree-dimensional wind speed (requires the CSAT3A)
osonic air temperature (requires the CSAT3A)
oair temperature
obarometric pressure
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EC150 CO2and H2O Open-Path Gas Analyzer
These measurements are required to compute carbon dioxide and water vapor
fluxes using the:
•Standard outputs:
oCO2density, H2O density
ogas analyzer diagnostic flags
oair temperature, air pressure
oCO2signal strength, H2O signal strength
oAir temperature and air pressure are auxiliary sensor inputs
•Additional outputs:
oux, uy, and uzorthogonal wind components
osonic temperature (based on the measurement of c, the speed of
sound)
osonic diagnostic flags
Datalogger compatibility: CR1000
CR3000
CR5000
Measurement
Rate: 100 Hz
Output bandwidth2:5, 10, 12.5, 20, or 25 Hz
Output rate2:10, 25 or 50 Hz
Operating temperature: -30oto +50oC
Gas analyzer
Measurement precision1
CO2 density: 0.2 mg·m-3 (0.15 µmol·mol-1)
H2O density: 0.00350 g·m-3 (0.006 mmol·mol-1)
Factory calibrated range
CO2:0 to 1000 µmol·mol-1
H2O: 0 mmol·mol-1 to 37oC dewpoint
Analyzer temp: -30oto +50oC
Baro pressure: 70 to 106 kPa
CO2performance
Zero max drift3:±0.55 mg·m-3·°C-1 (±0.3 μmol·mol·°C-1)
Gain drift: ±0.1% of reading·°C-1 (maximum)
Sensitivity to H2O: ±1.1 x 10-4 µmol CO2·mol-1 H2O (max)
H2O performance
Zero max drift3:±0.037 g·m-3·°C-1 (±0.05 mmol·mol-1·°C-1)
Gain drift: ±0.3% of reading·°C-1 (maximum)
Sensitivity to CO2:±0.1 mol H2O·mol-1 CO2 (maximum)
3

EC150 CO2and H2O Open-Path Gas Analyzer
CSAT3A sonic measurement precision4
ux:1 mm·s-1
uy:1 mm·s-1
uz:0.5 mm·s-1
Sonic temperature: 0.025oC
CSAT3A sonic accuracy5
Offset error
ux, uy:< ±8 cm·s-1
uz:< 4 cm·s-1
Gain error
Wind vector ±5° horizontal: < ±2% of reading
Wind vector ±10° horizontal: < ±3% of reading
Wind vector ±20° horizontal: < ±6% of reading
CSAT3 sonic reporting range
Full scale wind: ±65.553 m/s
Sonic temperature: -50° to +60°C
Auxiliary sensors6
Barometer
Basic barometer
Accuracy
-30 to 0°C: ±3.7 kPa at -30°C, falling linearly to ±1.5
kPa at 0oC
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
EC150 temperature sensor:
Manufacturer: BetaTherm
Model: 100K6A1A Thermistor
Accuracy: ±0.15oC (-30oto +50oC)
1 noise rms, assumes:
o25°C
o85 kPa
o14 g·m-3 H2O
o597 mg·m-3 CO2
o25 Hz bandwidth.
2 user selectable
3 -30° to 50°C
4 noise rms
5 assumes:
o-30° to +50°C
owind speed <30 m·s-1
oazimuth angles between ±170°
6 refer to manufacturer’s product brochure or manual for details
4

EC150 CO2and H2O Open-Path Gas Analyzer
5.2 Output Signals
Features
•EC100 electronics outputs data using:
oCS SDM
oRS-485
oUSB
oAnalog out
Digital
SDM (Synchronous Device for Measurement)1
Data type: FLOAT
RS-485
Data type: ASCII
Output Rate2:5 to 50 Hz
Baud rate2:1200 to 230400 bps
USB
Data type: ASCII
Output rate2: 10, 25 or 50 Hz
Analog (two outputs for CO2and H2O densities)
Voltage range: 0 mV to 5000 mV
Resolution: 76 µV (16 bit)
Update rate: 100 Hz
Accuracy (at 25oC): ±3 mV
CO2density equation: mg·m-3 = 0.38632·(mVout) - 102.59
Full scale range: -103 to 1829 mg·m-3
H2O density equation: g·m-3 = 0.00865·(mVout) - 2.26
Full scale range: -2 to 41 g·m-3
1Synchronous 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
5.3 Physical Description
Optical measurement path length: 15.37 cm (6.05 in)
Spatial separation from
CSAT3A sampling volume: 5.0 cm (2.0 in)
Dimensions
Head housing diameter: 3.2 cm (1.25 in)
Head length: 29.7 cm (11.7 in)
EC100 enclosure: 24.1 cm x 35.6 cm x 14 cm (9.5 in x
14 in x 5.5 in)
Weight
Analyzer and cable: 2 kg (4.4 lbs)
EC100 electronics and
EC100 enclosure: 3.2 kg (7 lbs)
5

EC150 CO2and H2O Open-Path Gas Analyzer
FIGURE 5-1. Dimensions of EC150 analyzer head
5.4 Power Requirements During Power-up and Operation
Voltage supply: 10 to 16 Vdc
Power at 25°C including CSAT3A: 5.0 W
Power at 25°C excluding CSAT3A: 4.1 W
Power at 25°C in power-down
mode (CSAT3A fully powered and
EC150 in stand-by): 3.0 W
6. Installation
6.1 Orientation
During operation the EC150 should be positioned vertically (±15 degrees) so
that the product label reads right-side-up and the upper arm (source) is directly
above the lower arm (detector). If the sensor is being used with a sonic
anemometer, it should be leveled and pointed into the prevailing wind to
minimize flow distortion from the analyzer’s arms and other supporting
structures.
6.2 Mounting
The EC150 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 EC150 mounting hardware also
accommodates an optional CSAT3A sonic anemometer. The following steps
describe the normal mounting procedure. Refer to FIGURE 6-1 or FIGURE
6-2 throughout this section.
6

EC150 CO2and H2O Open-Path Gas Analyzer
a. Secure a CM20X crossarm (pn 1790X) to a tripod or other vertical
structure using a CM210 crossarm-to-pole bracket (pn 17767).
b. Point the horizontal arm into the direction of the prevailing wind. Tighten
all the fitting set screws.
Do not carry the EC150 or the CSAT3A by the arms or
the strut between the arms. Always hold them by the
block, where the upper and lower arms connect.
WARNING
c. If a CSAT3A is being used, bolt the EC150/CSAT3A mounting bracket
(pn 26786) to the CM250 leveling mount (pn 26559) (see FIGURE 6-1).
Next install the CSAT3A sonic head to the EC150/CSAT3A mounting
bracket by aligning the threaded hole on the CSAT3A sonic head with the
hole on the bracket. Insert and finger-tighten the bolt, making sure there is
no cross-threading. Finish tightening with a wrench. Install the assembly
to the end of the crossarm by fitting the leveling mount over the end of the
crossarm. Tighten the set screws on the leveling mount. The EC150 gas
analyzer head may now be installed to the EC150/CSAT3A mounting
bracket. To do this, tighten the mounting screw and loosely thread the
mounting bolt into the analyzer head. Next align the analyzer parallel with
the vertical plate of the mounting bracket and insert the mounting screw
and bolt into the mounting bracket slot. Carefully slide the analyzer
forward. Avoid crashing the arms of the sensors together. The arms of the
analyzer should slide in between the claws of the CSAT3A; the sonic head
may need to be loosened and repositioned to do this. Tighten the bolts.
Make sure that the analyzer is vertically oriented so that the label is right-
side-up and the upper arm (source) is directly above the lower arm
(detector).
7

EC150 CO2and H2O Open-Path Gas Analyzer
CSAT3A Sonic Head
EC150/CSAT3A
Mounting Bracket
(pn 26786)
FIGURE 6-1. Exploded view of mounting the CSAT3A sonic head and
EC150 gas analyzer head
FIGURE 6-2. Exploded view of mounting the EC150 gas analyzer head
without the CSAT3A
EC150 Gas
Analyzer Head
CM250 Leveling Mount
(pn 26559)
EC150 Gas
Analyzer Head
EC150 Head-Only
Mounting Bracke
t
(pn 26785)
CM250 Leveling Mount
(pn 26559)
8

EC150 CO2and H2O Open-Path Gas Analyzer
Over-tightening bolts will damage or deform the
mounting hardware.
WARNING
d. If a CSAT3A is not being used, bolt the EC150 head-only mounting
bracket (pn 26785) to the CM250 leveling mount (pn 26559) (see FIGURE
6-2). Mount the EC150 gas analyzer head to the EC150 head-only
mounting bracket. To do this, tighten the mounting screw into the back,
lower hole of the analyzer head, and place the mounting bracket on the
analyzer head so that mounting screw fits into the bracket’s small hole.
The other hole in the bracket should line up with the threaded hole on the
analyzer. Insert the mounting bolt through the holes and tighten. Now
mount this assembly to the end of the crossarm by fitting the leveling
mount over the end of the crossarm. Tighten the set screws on the leveling
mount.
Use caution when handling the EC150 gas analyzer head.
The optical source may be damaged by rough handling,
especially while the EC150 is powered.
CAUTION
The CSAT3A sonic anemometer is an updated version of the
CSAT3, designed to work with the EC100 electronics. An
existing CSAT3 maybe upgraded to a CSAT3A. Contact
Campbell Scientific for details.
NOTE
e. If the assembly is not level, slightly loosen the bolt that holds the
mounting bracket on the leveling mount and adjust the assembly. If the
CSAT3A is being used, adjust the assembly until the leveling bubble on
the top of the CSAT3A head is within the bullseye. Retighten the bolt.
f. 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 6-3). 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 6-4).
9

EC150 CO2and H2O Open-Path Gas Analyzer
FIGURE 6-3. EC100 enclosure mounting bracket mounted on a vertical
mast (left) and a tripod leg (right)
FIGURE 6-4. Exploded view of mounting the EC100 enclosure
10

EC150 CO2and H2O Open-Path Gas Analyzer
g. Mount the EC150 temperature probe so that it measures temperature at the
same height as the sample volume of the EC150 and CSAT3A. To do this,
first attach the R.M. Young 41303-5A 6-plate solar radiation shield (pn
4020) to the mast with the included u-bolt. Next insert the end of the
temperature probe into the hole on the bottom of the shield. Tighten the
screws to hold the probe in place. For more detailed information about the
temperature probe installation and specifications, refer to the Model 107
Temperature Probe instruction manual.
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.
6.3 Wiring and Connections
FIGURE 6-5 and FIGURE 6-6 below show EC100 electronics panel and the
bottom of the EC100 enclosure, respectively. Refer to these figures during
wiring and connecting.
FIGURE 6-5. EC100 electronics front panel. The one on the left shows
how the EC100 will look shipped from the factory (enhanced
barometer shown). The one on the right shows the panel after the
user has done all the wiring and made all connections (basic
barometer shown).
11

EC150 CO2and H2O Open-Path Gas Analyzer
FIGURE 6-6. Bottom of EC100 enclosure
a. Connect the EC150 gas analyzer head. Begin by removing the black
rubber cable entry plug (pn 26224) on the bottom right of the EC100
enclosure. (This plug can be stored in the mesh pocket of the enclosure).
Now insert the cable entry plug that is attached to the large cable of the
EC150 gas analyzer head into the vacant slot. Push the connector at the
end of the cable onto its mating connector (labeled Gas Analyzer) and
tighten the thumbscrews (see FIGURE 6-6). The EC150 gas analyzer
cable is approximately 3 meters in length.
b. Connect the CSAT3A sonic head (skip this step if not using the CSAT3A).
Similar to (a), begin by removing the black rubber cable entry plug found
on the bottom left of the EC100 enclosure. Insert the cable entry plug on
the CSAT3A cable into the slot and connect the male end to the female
connector labeled Sonic Anemometer on the EC100 electronics (see
FIGURE 6-6). The CSAT3A cable is approximately 3 meters in length.
Unlike previous models of the CSAT3 3D sonic anemometer, the
CSAT3A sonic head and the EC150 gas analyzer head have
embedded calibration information. This means that any
CSAT3A and any EC150 may be used with any EC100.
NOTE
c. Connect the EC150 temperature probe. Unscrew the temperature
connector cover, which is found on the bottom of the EC100 enclosure
(see FIGURE 6-6). Insert the 3-prong temperature probe connector into
the female connector on the enclosure and screw it firmly in place. The
EC150 temperature probe cable is approximately 3 meters in length.
12