Xylem EXO1, EXO2 User Manual
EXO
User Manual
ADVANCED WATER QUALITY MONITORING PLATFORM
Item# 603789REF
Revision A
e information contained in this manual is subject to
change without notice.
Eort has been made to make the information in
this manual complete, accurate, and current. e
manufacturer shall not be held responsible for errors or
omissions in this manual. Consult EXOwater.com for the
most up-to-date version of this manual.
Table of Contents
1. Introduction
1.1 EXO1 Sonde Overview
1.2 EXO2 Sonde Overview
1.3 EXO Handheld Overview
1.4 EXO Sensors Overview and Specications
1.5 Conductivity/Temperature
1.6 Depth and Level
1.7 Dissolved Oxygen
1.8 fDOM
1.9 pH and ORP
1.10 Total Algae (Chlorophyll and Blue-green Algae)
1.11 Turbidity
2. Operation
2.1 Install Batteries
2.2 Install/Remove Sensors
2.3 Install/Remove Sensor Guard or Calibration Cup
2.4 Sonde States and LED Descriptions
2.5 Awake Sonde, Activate Bluetooth
Attach Sonde to Handheld
2.6 Field Cable
2.7 Bluetooth Wireless Communication
2.8 Install KOR Soware
Connect Sonde
2.9 USB
2.10 Bluetooth Link to PC
2.11 Data Collection Platform
2.12 Flow Cell
3. Handheld
3.1 Install Batteries
3.2 Power On/O Handheld
Attach Handheld to Sonde
3.3 Field Cable
3.4 Bluetooth Wireless Communication
Spot Sampling
3.5 View Live Data
3.6 Record Spot Sampling Data
3.7 Upload Data
3.8 GPS
4. KOR Software
4.1 Introduction to Navigation
4.2 Run Menu
4.3 Calibrate Menu
4.4 Deploy Menu
4.5 Sites Menu
4.6 Data Menu
4.7 Options Menu
4.8 Connections Menu
4.9 Help Menu
4.10 Data Files & File Locations
4.11 SDI-12
pg | 3
5. Calibration
5.1 Introduction to Basic Procedure
5.2 Calibrating Conductivity/Temperature
5.3 Calibrating Dissolved Oxygen
5.4 Calibrating Depth
5.5 Calibrating pH
5.6 Calibrating ORP
5.7 Calibrating Turbidity
5.8 Calibrating Total Algae (Chlorophyll and Blue-green Algae)
5.9 Calibrating fDOM
5.10 Calibration Standards
5.11 Calibration Record Sheet
6. Maintenance
6.1 Sonde Storage, Short-term and Long-term
6.1 Sonde Maintenance
6.2 Install/Replace Sonde Batteries
6.3 Replace Sonde Bails
6.4 Update Sonde Firmware
6.5 Handheld Maintenance and Storage
6.6 Install/Replace Handheld Batteries
6.7 Update Handheld Firmware & KOR Soware on Handheld
6.8 Depth Sensor Storage and Maintenance
6.9 Standard Optical Sensors Maintenance and Storage
6.10 Conductivity/Temperature Sensor Maintenance and Storage
6.11 Dissolved Oxygen Sensor Storage, Maintenance and Rehydration
6.12 Sensor Cap Replacement
6.13 pH and ORP Sensor Storage, Maintenance and Rehydration
6.14 Sensor Module Replacement
6.15 Wiper Maintenance and Storage
6.16 Field Cable Maintenance and Storage
6.17 Antifouling Equipment Maintenance
Sacricial Anode
6.18 Connectors Maintenance and Storage
6.19 Flow Cell Maintenance
pg | 4
7. Health & Safety, Warranty, Service
7.1 Chemicals
Conductivity Solutions
pH Solutions
Zobell Solution
Turbidity Standard
Ultraviolet Light (fDOM Sensor)
7.2 Radio Frequency
7.3 Declarations of Conformity
7.4 Instrument Warranty
7.5 Instrument Cleaning & Packing Instructions
7.6 Recycling
2.9
EXO 1 Sonde
1.1
Overview
e EXO1 sonde is a multiparameter instrument that collects water quality data. e sonde collects the
data with up to four user-replaceable sensors and an integral pressure transducer. Each sensor measures its
parameter via a variety of electrochemical, optical, or physical detection methods. Each port accepts any EXO
sensor and automatically recognizes its type. Depending on user-dened settings, the EXO1 will collect data
and store it onboard the sonde, transfer the data to a data collection platform (DCP), or relay it directly to
a user’s PC or EXO Handheld.
Users communicate with the sonde via a eld cable to an
EXO Handheld, Bluetooth® wireless connection to a PC or
EXO Handheld, or a USB connection (via communications
adapter) to a PC.
Specifications
Operating
Environment
Depth Rating
Medium
Material
Internal Logging
Memory Capacity
250 meters, 820 feet
Water
®
Xenoy
titanium, copper-nickel
alloy, 316 stainless steel
512 MB
, Lexan® , bronze,
Universal Sensor Ports
Software
Communications
Sonde
Adapters
Power
External
Internal
Temperature
Operating
Storage
Battery Life
Dimensions
Diameter
Length
Weight
Kor Interface Software
Bluetooth, Field Cable,
USB, RS-485;
USB, SDI -12/RS -232
9-16 VDC
2 D - size batteries
-5 to 50°C
+
-20 to
90 days typically
(see pg 78)
4.70 cm,1.85 in
64.77 cm, 25.50 in
1.65 kg, 3.63 lb
80°C
pg | 5
EXO1 Sonde
599501
Removable Bail
599473
6-Pin Cable Connector
Upper Battery
Compartment Seal
O-rings 599680
Battery Compartment
Battery Cover
Lower Battery
Compartment Seal
Pressure Transducer
Opening
Red LED Indicator
– Sonde
Status
Blue LED Indicator – Bluetooth
On/Off Magnetic Switch for
Power and Bluetooth
Bulkhead
Sensor
Port Plug
599475
Calibration Cup
599289
Sensor Guard
599333, 599563
pg | 6
Guard Weight
599471, 599365
2.9
EXO2 Sonde
1.2
Overview
e EXO2 sonde is a multiparameter instrument that collects water quality data. e sonde collects the
data with up to six user-replaceable sensors and an integral pressure transducer. Each sensor measures its
parameter via a variety of electrochemical, optical, or physical detection methods. Each port accepts any EXO
sensor and automatically recognizes the type of sensor. Depending on user-dened settings, the EXO2 will
collect data and store it onboard the sonde, transfer the data to a data collection platform (DCP), or relay it
to a user’s PC or EXO Handheld via cable, USB connection, or Bluetooth connection.
In addition to six standard sensor ports, the EXO2 also has a bulkhead port for a central wiper (or an
additional sensor) and an auxiliary port on top of the sonde. is auxiliary port will allow the user to connect
the EXO2 to other EXO sondes.
Users communicate with the sonde via a eld cable to an
EXO Handheld, Bluetooth® wireless connection to a PC or
EXO Handheld, or a USB connection (via communications
adapter) to a PC.
Specifications
Operating
Environment
Pressure Transducer
Openings
Depth Rating
Medium
Material
Internal Logging
Memory Capacity
Software
250 meters, 820 feet
Water
Xenoy, Lexan, bronze,
titanium, copper-nickel
alloy, 316 stainless steel
512 MB
Kor Interface Software
Wiper/Sensor Port
Universal Sensor Ports
Communications
Sonde
Adapters
Power
External
Internal
Temperature
Operating
Storage
Battery Life
Dimensions
Diameter
Length
Weight
Bluetooth, Field Cable,
USB, RS-485;
USB, SDI -12/RS -232
9-16 VDC
4 D - size batteries
+
-5 to
-20 to
90 days typically
(see pg 80)
7.62 cm, 3.00 in
71.1 cm, 28.00 in
2.65 kg, 5.83 lb
50°C
+
80°C
pg | 7
EXO2 Sonde
599502
Removable Bail
599474
Auxiliary Port
6-Pin Cable Connector
Battery Cap/Pressure Relief Valve
O-rings 599681
Battery Compartment Opening
Battery Compartment
pg | 8
On/Off Magnetic Switch for
Power and Bluetooth
Red LED Indicator
– Sonde
Status
Blue LED Indicator – Bluetooth
Bulkhead
Sensor
Port Plug
599475
Sensor Guard
599334, 599564
Calibration Cup
599316
Central Wiper
599549
Guard Weight
599472, 599366
2.9
EXO Handheld
1.3
Overview
e EXO Handheld (HH) is a rugged, microcomputer-based instrument that allows the user to display sonde
readings, congure sondes, store and retrieve data, and transfer data from sondes to a computer. Equipped with
GPS, barometer, and custom operating system, the Handheld communicates via Bluetooth wireless technology,
eld cable, or USB connector. e unit utilizes an adjustable backlit screen for easy day or night viewing. Preinstalled KOR soware facilitates all user interaction and provides powerful control over data collection.
Top View
Specifications
US B Port
Speaker
Microphone is for future
functionality; not active yet
Magnet
GPS Antenna
Tripod Mount
(1)
Barometer
Vent
Handstrap
Mount
Battery Cover
(internal)
Back View
Barometer
GPS
Microphone
Audio Speaker
Operating
System
Material
Memory
Software
Communications
Power
Internal
Temperature
Operating
Storage
Dimensions
Width
Length
Weight w. batt.
Yes
Yes
Yes
Yes
Windows CE 5.0
Polymer,
rated to IP-67 in factory
tests
2 GB
Kor Interface Software
Bluetooth, Field Cable,
USB
4 C - size alkaline batteries
+
-5 to
-20 to
11.9 cm, 4.7 in
22.9 cm, 9.0 in
0.91 kg, 2.1 lb
50°C
+
80°C
Handstrap
Mount
pg | 9
EXO Handheld
599150
Bluetooth Indicator
Wi-Fi Indicator is for future
functionality; not active yet
Daylight-viewable
LCD
Soft Keys (2)
Menu
Escape
Navigation Arrows (4)
& Return
Backspace
Tab
Power
Brightness
Alphanumeric
Keypad
Shift
pg | 10
Cable Connector
EXO Sensors
1.4
Overview
e EXO product line includes nine sensors that detect a variety of physical, chemical, and biological
properties of natural water. EXO sensors are designed to collect highly accurate data under ever-changing
environmental conditions.
Data Filtering
All EXO sensors share some common embedded soware, including the ltering of real-time data. Sensors
acquire environmental data at a constant rate, and use this stream of data as the input to the ltering algorithm
that produces results seen by the user. EXO sondes collect data from the EXO sensors and are able to output
data at rates up to 4 Hz. e EXO sensor data ltering process consists of four components:
Basic Rolling Filter
e lter is fundamentally a rolling or window average of past acquired inputs to the lter, such that as a new
data value is added to the summation, the oldest data value is removed, and the total summation is divided
by the total number of data values. It is a simple average, just rolling or moving in time.
Adaptive Filtering
e drawback to a basic rolling lter is that response time to an impulse event is delayed, and the more entries
in the average summation, the longer the delay for the result to converge on the true value. To correct this,
the lter algorithm monitors the new data arriving and compares it to the current averaged result, looking
for indication of an impulse event. When new data deviates from the average by more than a predetermined
tolerance, the number of data entries within the rolling average is reduced to a minimum count and the
remaining values are ushed with the new data. e result is a snap to the new value, entirely eliminating
the inherent delay caused by the rolling average.
Outlier Rejection
Every time a newly acquired data value is added, the rolling average entries are scanned for outlier data.
Although such data has already been determined to fall within the tolerances dened above, the remaining
worst oenders are removed from the rolling average calculation. is outlier rejection allows for smoother
continuous data results.
Calibration Stability
During calibration, the ltering is active as described, plus an additional feature works to provide stability
feedback to the user. When the user attempts to calibrate a sensor, the sudden changes in environment
are perceived as impulses or plunge events and the ltering reacts accordingly. e results immediately
show the value of the solution, and aer a few moments, the lter incrementally engages fully and supplies
the smoothest data. However, as the sensor and the calibration solution work towards equilibrium, the
measurement may slowly dri. e sensor will monitor the results from the lter and determine if the
measurement is stable. It watches the results and calculates a slope from each and every result to the next.
Once the slope settles and is consistently at for approximately 30 seconds, the sensor is considered stable.
KOR is then notied and calibration can continue.
pg | 11
Sensor Response Times
Response times for EXO sensors are based on laboratory testing. Actual response times in the eld may vary
depending on application.
Sensor Accuracy Specifications
To maintain accuracy specications for EXO sensor, we recommend that users calibrate sensors in the lab in
standards with temperatures as close to the ambient temperature of the eld water as possible.
pg | 12
2.9
Conductivity/Temperature
1.5
Sensor Overview
e EXO combination conductivity and temperature sensor should be installed in a sonde in nearly all sonde
applications. Not only will this sensor provide the most accurate and fastest response temperature data, but
it will also provide the best data for the use in temperature compensation for the other EXO probes. e
conductivity data is used to calculate salinity, specic conductance, and total dissolved solids, and compensate
for changes in density of water (as a function of temperature and salinity) in depth calculations if a depth
sensor is installed.
Temperature Thermistor
e temperature sensor uses a highly stable and aged
thermistor with extremely low-dri characteristics. e
Conductivity Cell
Specifications
Conductivity
Default Units
Temperature
Operating
Storage
Range
Accuracy
Response
Resolution
Sensor Type
Temperature
microSiemens/centimeter
-5 to +50°C
-20 to +80°C
0 to 200 mS/cm
0-100 mS/cm: ±0.5% of
reading or 0.001 mS/cm,
whichever is greater;
100-200 mS/cm: ±1% of
reading
T63<2 sec
0.0001 to 0.01 mS/cm
range-dependent
4-electrode nickel cell
(see pg 12)
(continued)
599870
Default Units
Temperature
Operating
Storage
Accuracy
Response
Resolution
Sensor Type
°Celsius
-5 to +50°C
-20 to +80°C
-5 to 35°C: ±0.01°C
35 to 50°C: ±0.05°C
T63<1 sec
0.001°C
Thermistor
pg | 13
thermistor’s resistance changes with temperature. e measured resistance is then converted to temperature
using an algorithm. e temperature sensor receives a multi-point NIST traceable wet calibration and the
accuracy specication of 0.01˚C is valid for expected life of the probe. No calibration or maintenance of the
temperature sensor is required, but accuracy checks can be conducted and logged through the KOR interface
soware.
Conductivity Electrodes
e conductivity sensor uses four internal, pure-nickel electrodes to measure solution conductance. Two of
the electrodes are current driven, and two are used to measure the voltage drop. e measured voltage drop is
then converted into a conductance value in milliSiemens (millimhos). To convert this value to a conductivity
value in milliSiemens per cm (mS/cm), the conductance is multiplied by the cell constant that has units of
reciprocal cm (cm-1). e cell constant for the conductivity cell is approximately 5.5/cm ±10%. For most
applications, the cell constant is automatically determined (or conrmed) with each deployment of the system
when the calibration procedure is followed.
Temperature Compensation
EXO sensors have internal thermistors for quality assurance purposes. However, this internal temperature
is not logged or displayed. Turbidity uses the internal thermistor for temperature compensation, while all
other EXO sensors reference the C/T probe for temperature compensation. To display and log temperature,
a C/T probe must be installed in an EXO sonde.
pg | 14
Depth
1.6
Sensor Overview
EXO measures depth of water with a non-vented strain gauge. A dierential strain gauge transducer
measures pressure with one side of the transducer exposed to the water and the other side exposed to a
vacuum. We calculate depth from the pressure exerted by the water column minus atmospheric pressure.
Factors inuencing depth measurement include barometric pressure, waterdensity, and temperature.
Calibration in the atmosphere “zeros” the sensorwith respect to the local barometric pressure. A change in
barometricpressure will result in a zero shi unless the transducer is recalibrated to the new pressure.
EXO sondes have intake openings to allow water to act on the strain gauge. e EXO1 intake is located in
the yellow section between the battery compartment and
label of the sonde. e EXO2 intake openings are two small
holes on the face of the sonde bulkhead.
Location of Depth Sensor
Depth sensors are not on center. When deploying the sonde
vertically, take care to ensure the sonde is redeployed in
same position. Oen a marker pin inside a PVC pipe is
used. In horizontal deployments, take care to ensure the
redeployments are always in the same orientation. is is
especially important for the EXO2 sonde because the depth
EXO 2 Depth Intake
EXO 1 Depth Intake
sensor is o-axis.
(continued)
Specifications
Depth Sensor Location relative
to other water quality sensors
(see EXO sonde label)
Depth Sensor Location
27.2 cm to WQ Sensors
Units
Temperature
Operating
Storage
Range
Accuracy
Response
Resolution
Sensor Type
PSI, Depth (m, ft, bar)
-5 to +50°C
-20 to +80°C
Shallow: 0 to 33 ft (10 m)
Medium: 0 to 328 ft (100 m)
Deep: 0 to 820 ft (250 m)
Shallow: ±0.04% FS (±0.013
ft or ±0.004 m)
Medium: ±0.04% FS (±0.13 ft
or ±0.04 m)
Deep: ±0.04% FS (±0.33 ft or
±0.10 m)
T63<2 sec
0.001 ft (0.001 m)
Stainless steel strain gauge
(see pg 12)
pg | 15
Location of Depth Sensor (continued)
To assist with consistent horizontal orientation, the EXO2 sonde has
an indentation at the top of the sonde for a marker or positioning
pin.
e sonde should be installed with at least 1 cm of water above the
intake ports.
If a conductivity sensor is installed, the depth will be compensated
automatically for changes in the density of water as temperature
and salinity change.
Depth Configuration
EXO sondes must be ordered with a specic depth option: 0-10 m,
0-100 m, 0-250 m, or no depth. Once the depth selection is made,
the sonde’s depth sensor cannot be changed.
pg | 16
2.9
Dissolved Oxygen
1.7
Sensor Overview
e principle of operation of the EXO optical Dissolved Oxygen sensor is based on the well-documented
concept that dissolved oxygen quenches both the intensity and the lifetime of the luminescence associated
with a carefully chosen chemical dye. e EXO DO sensor operates by shining a blue light of the proper
wavelength on this luminescent dye which is immobilized in a matrix and formed into a disk. e blue
light causes the immobilized dye to luminesce and the lifetime of this dye luminescence is measured via a
photodiode in the probe. To increase the accuracy and stability of the technique, the dye is also irradiated with
red light during part of the measurement cycle to act as a reference in the determination of the luminescence
lifetime.
When there is no oxygen present, the lifetime of the signal
is maximal; as oxygen is introduced to the membrane
surface of the sensor, the lifetime becomes shorter. us,
the lifetime of the luminescence is inversely proportional
Sensor Cap
Sensor without
Sensor Cap
to the amount of oxygen present and the relationship
between the oxygen pressure outside the sensor and the
lifetime can be quantied by the Stern-Volmer equation.
For most lifetime-based optical DO sensors, this SternVolmer relationship
((Tzero/T) – 1) versus O2 pressure
is not strictly linear (particularly at higher oxygen
pressures) and the data must be processed using analysis by
(continued)
599100,
599110
Specifications
Units
Temperature
Operating
Storage
Range
Accuracy
Response
Resolution
Sensor Type
% Saturation, mg/L
-5 to +50°C
-20 to +80°C
0 to 500% air sat.
0 to 50 mg/L
0-200%: ±1% reading or 1%
air sat., whichever is greater;
200-500%: ±5% reading
0-20 mg/L: ±1% of reading or
0.1 mg/L;
20-50 mg/L: ±5% reading
T63<5 sec
0.1% air sat.
0.01 mg/L
Optical, luminescence lifetime
(see pg 12)
pg | 17
polynomial non-linear regression. Fortunately, the non-linearity does not change signicantly with time
so that, as long as each sensor is characterized with regard to its response to changing oxygen pressure, the
curvature in the relationship does not aect the ability of the sensor to accurately measure oxygen for an
extended period of time.
pg | 18
fDOM
1.8
Sensor Overview
e EXO fDOM (Fluorescent Dissolved Organic Matter) sensor is a uorescence sensor which detects the
uorescent component of DOM (Dissolved Organic Matter) when exposed to near-ultraviolet (UV) light.
Colored Dissolved Organic Matter
Users might wish to quantify colored dissolved oxygen matter (CDOM) in order to determine the amount of
light which is absorbed by stained water and thus is not available for the photosynthesis process carried out
by subsurface aquatic plants and algae. In most cases, fDOM can be used as a surrogate for CDOM.
Quinine Sulfate
A surrogate for fDOM is Quinine Sulfate, which, in acid
solution, uoresces similarly to dissolved organic matter.
e units of fDOM are quinine sulfate units (QSUs) where
1 QSU = 1 ppb quinine sulfate and thus quinine sulfate is
really a double surrogate for the desired CDOM parameter.
e EXO fDOM sensor shows virtually perfect linearity
2
=1.0000) on serial dilution of a colorless solution of
(R
WARNING
UV LIGHT
Do not look
directly at light.
quinine sulfate. However, on serial dilution of stained water
eld samples, the sensor shows some underlinearity. e
point of underlinearity in field samples varies and is
(continued)
599104
Specifications
Units
Temperature
Operating
Storage
Range
Response
Resolution
Sensor Type
Linearity
Detection Limit
Optics:
Excitation
Emission
Quinine Sulfate equivalents
(QSE), ppb
-5 to +50°C
-20 to +80°C
0 to 300 ppb QSE
T63<2 sec
0.01 ppb QSE
Optical, fluorescence
2
>0.999 for serial dilution
R
of 300 ppb Quinine Sulfate
solution
0.07 ppb QSE
365±5 nm
480±40 nm
(see pg 12)
pg | 19
aected by the UV absorbance of the DOM in the water. Testing shows that underlinearity can occur at fDOM
concentrations as low as 50 QSU. is factor means that a eld sample with an fDOM reading of 140 QSU will
contain signicantly more than double the fDOM of a sample that reads 70 QSU. is eect—good linearity
in colorless quinine sulfate solution, but underlinearity in stained eld samples—is also exhibited by other
commercially available fDOM sensors and thus the performance of the EXO sensor is likely to be equivalent
or better than the competition while providing the advantages of easy integration into a multiparameter
package and automatic mechanical cleaning when used in monitoring studies with an EXO2 sonde.
pg | 20
2.9
pH and ORP
1.9
Sensor Overview
Users can choose between a pH sensor or a combination pH/ORP sensor to measure these parameters. pH
describes the acid and base characteristics of water. A pH of 7.0 is neutral; values below 7 are acidic; values
above 7 are alkaline. ORP designates the oxidizing-reducing potential of a water sample and is useful for
water which contains a high concentration of redox-active species, such as the salts of many metals and strong
oxidizing (chlorine) and reducing (sulte ion) agents. However, ORP is a non-specic measurement—the
measured potential is reective of a combination of the eects of all the dissolved species in the medium.
Users should be careful not to overinterpret ORP data unless specic information about the site is known.
(continued)
Specifications
pH
Units
Temperature
Operating
Storage
Range
Accuracy
Response
Resolution
Sensor Type
ORP
Units
Temperature
Operating
Storage
pH units
-5 to +50°C
0 to 60°C
0 to 14 units
±0.1 pH units within ±10°C
of calibration temperature;
±0.2 pH units for entire temp
range
T63<3 sec
0.01 units
Glass combination electrode
millivolts
-5 to +50°C
0 to 60°C
(see pg 12)
EXOISE1, EXOISE2,
EXOISE5, EXOISE6,
599795, 599797
Range
Accuracy
Response
Resolution
Sensor Type
-999 to +999 mV
±20 mV in Redox standard
solution
T63<5 sec
0.1 mV
Platinum button
(see pg 12)
pg | 21
Replaceable Sensor Module
e EXO pH and pH/ORP sensors have a unique design that incorporates a user-replaceable sensor tip
(module) and a reusable sensor base that houses the processing electronics, memory, and wet-mate connector.
is allows users to reduce the costs associated with pH and pH/ORP sensors by only replacing the relatively
inexpensive module periodically and not the more costly base.
e connection of the module to the sensor base is designed for one connection only and the procedure must
be conducted in an indoor and dry environment. Once installed the module cannot be removed until you
are prepared to replace it with a new module. See section 6.14 for detailed instructions.
Users must order either a pH or pH/ORP sensor. Once ordered the sensor is only compatible with like-model
sensor modules. For example, if a pH sensor is purchased initially, then the user must order a replaceable pH
sensor module in the future; it cannot be replaced with a pH/ORP module.
Electrodes
EXO measures pH with two electrodes combined in the same probe: one for hydrogen ions and one as a
reference. e sensor is a glass bulb lled with a solution of stable pH (usually 7) and the inside of the glass
surface experiences constant binding of H+ ions. e outside of the bulb is exposed to the sample, where the
concentration of hydrogen ions varies. e resulting dierential creates a potential read by the meter versus
the stable potential of the reference.
e ORP of the media is measured by the dierence in potential between an electrode which is relatively
chemically inert and a reference electrode. e ORP sensor consists of a platinum button found on the tip
of the probe. e potential associated with this metal is read versus the Ag/AgCl reference electrode of
the combination sensor that utilizes gelled electrolyte. ORP values are presented in millivolts and are not
compensated for temperature.
Amplification
Signal conditioning electronics within the pH sensor improve response and increase stability. Amplication
(buering) in the sensor head is used to eliminate any issue of humidity in the front-end circuitry and reduce
noise. Finally, the EXO pH sensor is insensitive to proximal interference during calibration due to having the
circuit next to the sensor and having a well-shielded pH signal.
pg | 22
Total Algae (Chl & BGA-PC)
1.10
Sensor Overview
e EXO total algae sensor is a dual-channel uorescence sensor that generates two independent data sets;
one resulting from a blue excitation beam that directly excites the chlorophyll a molecule, present in all
photosynthetic cells, and a second from an orange excitation beam that excites the phycocyanin accessory
pigment found in blue-green algae (cyanobacteria). is orange excitation triggers a transfer of energy from
the phycocyanin to the central chlorophyll a, where photosynthesis is initiated.
Although blue-green algae contain chlorophyll a, the chlorophyll uorescence signal detected by in situ
uorometers is weaker than in eukaryotic phytoplankton. is results in an underestimate of algae biomass when
using a single-channel chlorophyll sensor when blue-green
algae are present. e EXO total algae sensor generates a more
accurate total biomass estimate of the planktonic autotrophic
a
and
community by exciting chlorophyll
Specifications
Units
Chlorophyll
BGA - PC
Temperature
Operating
Storage
Range
RFU, µg/L Chl
RFU, µg/L PC
-5 to +50°C
-20 to +80°C
Chl: ~0 to 400 µg/L Chl; 0 to
100 RFU
BGA-PC: 0 to 100 µg/L PC;
0 to 100 RFU
phycocyanin.
(continued)
599102
Response
Resolution
Sensor Type
Linearity
Detection
Limit
Optics:
Chl Excitation
PC Excitation
Emission
T63<2 sec
Chl: 0.01 µg/L Chl; 0.01 RFU
BGA-PC: 0.01 µg/L PC;
0.01 RFU
Optical, fluorescence
2
>0.999 for serial dilution
Chl: R
of Rhodamine WT solution from 0
to 400 µg/L Chl equivalents
BGA: R2>0.999 for serial dilution
of Rhodamine WT solution from 0
to 100 µg/L PC equivalents
Chl: 0.09 µg/L Chl
BGA-PC: 0.04 µg/L PC
.
470±15 nm
590±15 nm
685±20 nm
(see pg 12)
pg | 23
e sensor generates data in three formats: RAW, RFU, and an estimate of the pigment concentration in μg/L.
e RAW value is a value unaected by user calibrations and provides a range from 0-100, representing the per
cent of full scale that the sensor detects in a sample.
RFU stands for Relative Fluorescence Units and is used to set sensor output relative to a stable secondary
standard, such as Rhodamine WT dye. is allows users to calibrate sensors identically; for example, calibrating
all sensors in a network to read 100 RFU in a concentration of Rhodamine WT dye. e sensors can then be
deployed and generate data that is relative to all other sensors. Once a sensor is retrieved, it can be checked
against that same standard to assess sensor performance, dri, or the potential eects of biofouling.
e μg/L output generates an estimate of pigment concentration. e relationship between μg/L and sensor’s
RAW signal should be developed through following standard operating procedures of sampling the water body
of interest, collecting sensor data from sample, and then extracting the pigment to establish a correlation. e
higher the temporal and spatial resolution of the sampling, the more accurate this estimate will be.
Chlorophyll
e EXO chlorophyll sensor operates on the in vivo uorescence principle with no disruption of the cells
required to obtain either spot readings or long-term data. e EXO sensor has an excellent detection limit as
determined under laboratory conditions and this advantage should be realized in many eld applications.
EXO chlorophyll readings show excellent linearity on serial dilution of a surrogate solution of Rhodamine WT
2
>0.9999) and this should ensure relative accuracy of eld chlorophyll readings, i.e., a chlorophyll reading
(R
of 100 units will represent twice the algal content of water with a chlorophyll reading of 50 units. Also, EXO
chlorophyll readings show very low interference from turbidity, allowing for more accurate determination of
algal content during rainfall events which release both sediment and algae into the water. e EXO chlorophyll
sensor also exhibits very low interference from dissolved organics, increasing data accuracy.
Blue-green Algae
e EXO BGA readings show excellent linearity on serial dilution of a surrogate solution of Rhodamine WT
2
>0.9999) and this should ensure relative accuracy of eld BGA-PC readings, i.e., a BGA-PC reading of 100
(R
units will represent twice the algal content of water with a BGA-PC reading of 50 units. A signicant advantage
of the EXO BGA-PC sensor is that its readings show less interference from turbidity and this will allow for
much more accurate determination of BGA-PC content during rainfall events which release both sediment
and algae into the water.
pg | 24
2.9
Turbidity
1.11
Sensor Overview
Turbidity is the indirect measurement of the suspended solid concentration in water and is typically
determined by shining a light beam into the sample solution and then measuring the light that is scattered
o of the particles which are present. e suspended solid concentration is an important water quality factor
and is a fundamental measure of environmental change. e source of the suspended solids varies in nature
(examples include silt, clay, sand, algae, organic matter) but all particles will impact the light transmittance
and result in a turbidity signal.
e EXO Turbidity sensor employs a near-infrared light source and detects scattering at 90 degrees of the
incident light beam. According to ASTM D7315 method,
this type of turbidity sensor has been characterized as a
nephelometric near-IR turbidimeter, non-ratiometric
is method calls for this sensor type to report values in
formazin nephelometric units (FNU). FNU is the default
calibration unit for the EXO sensor but users are able to
change calibration units to nephelometric turbidity units
(NTU), raw sensor signal (RAW), or total suspended solids
(TSS) assuming the user enters the appropriate correlation
data.
e RAW value is a value unaected by user calibrations
and provides a range from 0-100, representing the per cent
of full scale that the sensor detects in a sample.
(continued)
#
.
599101
Specifications
Default Units
Temperature
Operating
Storage
Range
Accuracy
Response
Resolution
Sensor Type
Optics:
Excitation
#
ASTM D7315-07a “Test Method for Determination of
Turbidity Above 1 Turbidity Unit (TU) in Static Mode.”
FNU
-5 to +50°C
-20 to +80°C
0 to 4000 FNU
0-999 FNU: 0.3 FNU or
±2% of reading, whichever is
greater; 1000-4000 FNU: ±5%
of reading
T63<2 sec
0-999 NTU: 0.01 FNU
1000-4000 FNU: 0.1 FNU
Optical, 90° scatter
.
860±15 nm
(see pg 12)
pg | 25
While all turbidity sensors will read consistently in formazin, other calibration solutions and eld readings
will vary between dierent models of turbidity sensors. ese dierences are thought to be a result of diering
optical components and geometries and the resulting detection of varying suspended sediment characteristics.
is eect is inherent in the nature of every turbidity sensor, and as a result readings between dierent model
turbidity sensors are likely to show dierent eld values even aer calibration in the same standards.
For long-term, in situ continuous monitoring of turbidity, the EXO2 sonde has a wiper to clean the turbidity
sensor to avoid sensor fouling and maintain accuracy.
pg | 26
Install Batteries
2.1
e EXO1 Sonde uses two (2) D-cell alkaline batteries and the EXO2 Sonde uses four (4) D-cell alkaline
batteries as the recommended power source. Alternatively, the sonde may use rechargeable NiMH D-cell
batteries that you purchase. See detailed installation instructions Section 6.2
1. Remove battery cover.
EXO1: Twist the blue battery cover counterclockwise to
loosen, li up to remove.
nec essar y.
Do not remove the screws on the sonde’s electronics
compartment.
Use included wrench to loosen, if
EXO1
EXO2
EXO2: Unscrew and remove battery cap. Use included
wrench to loosen, if necessary.
2. Install batteries.
Insert the batteries with positive terminals (+) facing up
and negative terminals (-) facing down toward the probes.
3. Replace battery cover.
Replace the battery cover or cap and tighten until snug. Do
not overtighten.
pg | 27
Install/Remove Sensors
2.2
EXO sensors have identical connectors and identify themselves via onboard rmware; therefore, users can
install any probe into any universal sonde port. e exception is the wiper for the EXO2 sonde, which must
be installed in the central Port 7. Individual ports are physically identied by an engraved number on the
sonde bulkhead. Although the probes are wet-mateable, users should clean, lubricate, and dry the sonde and
sensors connectors prior to installation or service, when possible.
1 Remove probe or port plug.
Remove the calibration cup and sensor guard from the
sonde. Place the sonde on a clean, at surface and prevent
it from rolling. R
and place on a clean surface.
If removing a sensor,
nut and rotate counterclockwise to loosen. Pull the probe
straight out of the port and place on a clean surface.
Remove hydration caps or buer bottles on probes. Wipe
dry with a clean, lint-free cloth.
emove port plugs by pulling straight out
use the probe tool in the locking
2 Clean port and install sensor.
Visually inspect the port for contamination. If the port
is dirty or wet, clean it with a clean, lint-free cloth or
compressed air. Apply a light coat of Krytox grease to the
rubber mating surfaces of the connector.
Insert the sensor into the port by properly aligning the
connectors’ pins and sleeves (male and female contacts);
then press them rmly together.
3 Tighten locking nut.
Taking care not to cross-thread the grooves, nger-tighten
the locking nut clockwise. When the nut is seated against
the bulkhead, tighten it with probe tool until snug. Once
sensors or plugs are installed, reinstall the sensor guard to
protect sensors from impact damage.
Take care not to twist the probe body when tightening
and loosening the locking nut. Excessive twisting of the
probe can damage the connector and is not covered under
warranty.
pg | 28
Install/Remove Guard or
2.3
Calibration Cup
Sonde guards protect EXO sensors from impact throughout deployment. Users should always install the guard
prior to data collection. e calibration cup (cal cup) is used for storage and calibration. We recommend
using two guards: one for eld deployments and a second used exclusively for calibrations. Using a second
guard will minimize calibration solution contamination (especially for turbidity) and calibration errors. EXO
calibration cups install over an installed sonde guard. is conguration reduces the amount of standards
required for calibration.
1 Install/remove sonde guard.
Install guard by threading it onto the sonde bulkhead
threads. Rotate the guard clockwise on the bulkhead to
install. Rotate it counterclockwise to remove. Always
use one guard for deployment/storage and the other for
calibration only.
Take care not to let the guard damage unguarded pH or
pH/ORP sensors when installing and removing.
2 Install/remove calibration cup.
Before installation, loosen (but do not remove) the
cup’s clamping ring. en, with the sonde guard already
installed, slide the cal cup over the guard until the bottom
of the guard rests against the bottom of the cal cup. Tighten
the ring until snug. To remove the cal cup, loosen the ring
by 1/4 turn and pull the guard free from the cup.
pg | 29
Sonde States and
2.4
LED Descriptions
States
An EXO sonde is always in one of three operational states: O, Awake, and Asleep. ese states determine the
sonde’s current power usage and logging potential. When O , the sonde is not powered and cannot collect
data (no batteries installed, no topside power). Users can apply power to the sonde internally, using batteries,
or externally with an EXO eld cable attached from the topside port to an EXO Handheld, DCP or other
approved power source. Once power is applied to a sonde, it is either Awak e or Asleep.
When in an Asleep state, the sonde remains in a very low
States
Off: Not powered, no data
collection.
Asleep: Low power. Waiting for
command.
Awake: Full power. Ready to
collect.
LED Indicators
Blue LED – Bluetooth
None: Off, not active.
On Solid: On, not linked.
2 Hz Blink: On, successfully linked.
Red LED – Sonde State
None: Sonde is Off or Asleep
with logging disabled.
0.1 Hz Blink: Sonde is Asleep with
logging enabled.
1 Hz Blink: Sonde is Awake.
On: Sonde is Awake with faults.
power setting and waits for a user command or its next
scheduled logging interval. An Awake sonde is fully powered
and ready to collect data. Once awakened, a sonde remains
Awake for ve minutes aer its last communication via
Bluetooth or 30 seconds aer its last communication via
the topside port. e sonde also automatically awakens 15
seconds before its next scheduled logging interval.
LED Indicators
Each sonde has two LED indicators that show the sonde’s
status. The blue LED indicates the Bluetooth’s wireless
connection status. e red LED indicates the sonde’s current
state.
e Bluetooth light (blue) is activated by a magnet swipe at
the magnetic activation area. When the blue LED is o, the
Bluetooth is disabled. When the light is on continuously, the
Bluetooth is enabled, but no link has been established. When
the blue LED blinks at 2 Hz, the sonde’s Bluetooth is on, and
has established a link.
When the red sonde state LED is o, the sonde is either O
or Asleep and not logging. When it blinks at 0.1 Hz (once
every 10 seconds), the sonde is Asleep and logging is enabled.
When the red light blinks at 1 Hz, the sonde is Awak e and
has no faults. If the red light is lit continuously, the sonde is
Awake and has detected faults, such as problems with the
system that need to be xed prior to use.
pg | 30
Modes
Within the Awake state, the sonde has three modes, which
are activated via Kor soware. When “Inactive (O),” the
sonde does not log any data. In “Real-Time” mode, the
sonde continuously collects data at a user-specied interval
(default is 2 Hz). “Sample/Hold” mode allows users to easily
synchronize data between the sonde’s data logger and an
external data collection platform.
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