Dissolved Oxygen Logger Operation Manual - Zebra-Tech

Dissolved Oxygen Logger Operation Manual - Zebra-Tech
D-OptoLogger
Dissolved Oxygen Logger
Operation Manual
Software version 3.4
D-OptoLogger Operation Manual
Contents
1. Introduction………………..……………………………………………………………………………………………………………………... 1
Optical Sensor Technology……………………...…………………………………………………………………………………………………………………………..1
Features………………………………………………...…………………………………………………………………………………………………………………………... 1
2. D-OptoLogger Specifications ……………………………………………………………………………………………………………….2
Specifications………………………………………..……………………………………………………………………………………………………………………………. 2
Communication Cable Wiring Scheme…..……………………………………………………………………………………………………………………………. 2
3. Software ……………………………………………………………………………………………………………………………………………..3
Installation………………………………………………………………………………………………………………………………………………………………………….. 3
Operation………………….…………………………………………………………………………………………………………………………………………………………4
4. Operating the D-OptoLogger.…………………………………………………………………………………………………………….. 9
Installation……………………………………………………………………………..…………………………………………………………………………………………...9
Sealing the D-OptoLogger……..……………………………………………………………………………………………………………………………………….…… 9
Logging Endurance…………………………………………………………………..………………………………………………………………………………………. 10
Calibration……………………………..…………………………………………………………………………………………………………………………………………. 11
5. Maintenance……………………..…………………………………………………………………………………………………………….. 13
6. Troubleshooting……………………………………………………………………………………………………………………….…….…14
Interpreting the LED indicator…………………………………………………………………………………………………………………………………………… 14
Loss of communication……………………………………………………………………………………………………………………………………………………… 14
Zero value data…………………….…………………………………………………………………………………………………………………………………………… 14
Erractic dissolved oxygen readings……………………………………………………………………………………………………………………….…………… 14
7. Appendices….…..………………………………………………………………………………………………………………………………. 15
Appendix 1: Pressure Correction Chart…………………………………………………………………………………………………………………………..….15
Appendix 2: Useful Conversions…………………………………………………………………………………………………………………………………..…….16
8. Further Assistance ….……………………………………………………………………………………………………………………..… 17
D-OptoLogger Operation Manual
1. Introduction
The D-OptoLogger is a fully self-contained dissolved oxygen logger incorporating a dissolved oxygen
sensor, battery and low power data logger in a rugged compact underwater housing.
The D-OptoLogger uses a field-proven solid-state optical sensing system to measure dissolved oxygen. It
is highly stable over long periods of time, even in harsh conditions. The data is stored onboard in nonvolatile memory. The D-OptoLogger is setup and data offloaded using simple Windows based software
supplied with the instrument.
Optical Sensor Technology
Unlike conventional dissolved oxygen sensors, the D-OptoLogger sensing element utilizes fluorescence
to measure dissolved oxygen. The basic principle involves subjecting a fluorescing compound
(ruthenium) to a fixed wavelength of light. When the light source is removed, the compound emits a
fluorescence, the intensity of which is dependent on the oxygen levels present in the surrounding water.
An extremely stable electronic circuit has been designed to firstly excite the ruthenium and then
measure the intensity of the resulting fluorescence. Using this circuitry, the D-OptoLogger should
provide accurate dissolved oxygen measurements over many months without re-calibration.
Unlike conventional polarographic dissolved oxygen sensors, the optical method does not consume
oxygen. Consequently the measurement of dissolved oxygen by the D-OptoLogger is unaffected by
water movement. Also the D-OptoLogger does not utilize a membrane or any other consumables, thus
minimizing servicing requirements.
Features
Your D-OptoLogger offers the following features:

Accurate dissolved oxygen measurements over long periods without re-calibration

Low power consumption data logger

Windows based communication software

Minimal servicing requirements
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D-OptoLogger Operation Manual
2. D-OptoLogger Specifications
Specifications
Physical Dimensions
200mm long x 50mm diameter
Accuracy
Temperature:
DO:
+/- 0.1 degrees C
1% of reading or 0.02 PPM, whichever is greater
Resolution
Temperature:
DO saturation:
PPM
00.01 degrees C
000.01%
00.001 PPM
Sensor Drift
<1% per year (provided measurement interval ≥10 minutes)
Power Supply
1 x PP9-9 volt alkaline battery. Duracell or Energizer recommended
Power Consumption
12 mA during measurement, 0.03 mA between measurements
Memory Capacity
10080 data records.
Each data record consists of date, time, battery voltage, temperature,
dissolved oxygen % saturation, dissolved oxygen PPM
Depth Rating
Maximum 30m water depth
“O” Rings
2 of #128 (1½ x3/32”)
TABLE 1: D-OPTOLOGGER SPECIFICATIONS
Communication Cable Wiring Scheme
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D-OptoLogger Operation Manual
3. Software
The D-OptoLogger is supplied with the custom designed Windows based communication software
program “D-OptoLog”. This software:

Enables the user to communicate with the D-OptoLogger via a computer

Is used to setup the D-OptoLogger prior to deployment

Is used to download data from the D-OptoLogger to the PC after retrieval
Installation
The D-OptoLogger is supplied with a software CD that contains the file ‘Install D-OptoLogX.exe’ (X =
version number). Double clicking the file from Windows Explorer will initiate installation onto the PC.
The default installation destination is C:\Program Files\D-OptoLog. It is recommended that this
destination is accepted. This will result in the correct installation into the appropriate folders for either
XP or Vista operating systems.
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D-OptoLogger Operation Manual
Operation
The D-OptoLogger is supplied with a communication cable. This cable has a 9-pin serial plug on one end
and a 3.5mm jack plug on the other end.
The 9-pin plug is plugged into the serial port on the PC. If the PC does not have a serial port, a USB to
serial adaptor can be used. This adaptor plugs into the USB port on the PC and has a serial port that the
communication cable 9-pin plug can be plugged into.
The jack plug on the communication cable is plugged into the communication socket located inside the
D-OptoLogger housing. This is accessed by removing the D-OptoLogger end cap.
When D-OptoLog is started and the current port is unavailable, a port selection window opens
(Figure 1).
FIGURE 1: D-OPTOLOG SERIAL PORT SELECTION WINDOW
If the computer has a hardware serial port, it will typically be ‘Com 1’. If a USB to serial converter is
being used, the com port number will most likely be another number.
To determine the correct com port number when using a USB to serial converter it is necessary to open
the Device Manager. In Vista, the device manager can be opened directly from the Control Panel. With
XP, first open ‘Control Panel’, then open the ‘System’ folder, click on the ‘Hardware’ tab and then click
on the ‘Device Manager’ button. Once you have opened ‘Device Manager’, click on ‘Ports (COM & LPT)’
to extend the tree. The com port number for the USB to serial converter will be displayed.
Control
Panel
System
Hardware
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Device
Manager
Ports
(COM &
LPT)
D-OptoLogger Operation Manual
In the example in Figure 2, the com port is ‘Com 4’.
FIGURE 2: DEVICE MANAGER
NOTE!
The com port number assigned to the USB serial converter may change between
computer re-starts.
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D-OptoLogger Operation Manual
Once the correct port has been selected and the ‘OK’ button pressed, the computer will start
communicating with the D-OptoLogger. This may take up to 8 seconds. When communication has
started the D-OptoLog main window will open (Figure 3).
FIGURE 3: D-OPTOLOG MAIN WINDOW
The main window displays current dissolved oxygen (% saturation and PPM) and temperature (˚C) data
and is updated approximately once every second.
The serial number displayed is factory set and is unique to each D-OptoLogger. It corresponds to the
number displayed on the outside of the D-OptoLogger housing.
The logger setup section enables the operator to set the desired logger parameters.
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D-OptoLogger Operation Manual
The ‘Plot data’ button enables a graphical plot of historic D-OptoLogger data to be displayed on screen
(Figure 4).
FIGURE 4: ‘PLOT DATA’ SCREEN
The ‘Calibrate’ button opens the D-OptoLogger Calibration window (Figure 5). All calibration values are
calculated and stored internally by the D-OptoLogger. The ‘Restore Defaults’ button causes the DOptoLogger to resort back to the original factory calibrations. A full description of the calibration
procedure is outlined in the ‘Operating the D-OptoLogger’ section.
FIGURE 5: D-OPTOLOGGER CALIBRATION WINDOW
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D-OptoLogger Operation Manual
The ‘Altitude Correction’ button opens up the Pressure Correction Calculator which provides a tool for
pressure correcting the dissolved oxygen saturation content of fully aerated water (Figure 6). It will
accept either altitude (m) or barometric pressure (mBar).
NOTE!
By pressing the ‘Restore Defaults’ button, the original factory calibration values are
reinstated by the D-OptoLogger.
FIGURE 6: PRESSURE CORRECTION CALCULATOR
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D-OptoLogger Operation Manual
4. Operating the D-OptoLogger
Installation
The D-OptoLogger can be mounted in any orientation. The body can be clamped in position.
Avoid using excessive force. A safety wire can be attached to the eyelet swivel on the top cap
of the logger. It is not recommended that the D-OptoLogger is suspended solely from the
eyelet swivel.
NOTE!
A new battery should always be used when starting a deployment. Use good quality
alkaline batteries such as Duracell or Energizer.
Sealing the D-OptoLogger
The D-OptoLogger end cap features a dual ‘O’ ring sealing system. It is essential that these ‘O’
rings are properly serviced and maintained, otherwise moisture may penetrate the housing.
The ‘O’ rings must be cleaned and lubricated each time the end cap is replaced prior to
underwater deployment.
1) Using the ‘O’ ring pick supplied, remove the ‘O’ rings from the inside of the end cap and
the body of the D-OptoLogger.
2) Using a lint free tissue, clean the ‘O’ ring seats, the corresponding ‘O’ ring surfaces and
both ‘O’ rings.
3) Lightly grease both ‘O’ rings with the grease supplied with your D-OptoLogger.
4) Replace the ‘O’ rings, ensuring no hairs or particles become trapped under them.
5) Screw the end cap onto the D-OptoLogger body. Do not over tighten.
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D-OptoLogger Operation Manual
Logging Endurance
The D-OptoLogger can log 10,080 data records into non-volatile memory. Each data record
consists of the time and date, battery voltage, dissolved oxygen percent saturation, PPM and
temperature (See Table 2).
Data Field Number:
Description:
1
Year
2
Month
3
Day
4
Hour
5
Minute
6
Second
7
Battery voltage
8
9
Temperature (Degrees C)
Dissolved Oxygen (%)
10
Dissolved Oxygen (PPM)
TABLE 2: DATA FILE FORMAT
Data is retained in the non-volatile memory until a new logging session is started, at which
point the memory is cleared of the previous data.
Memory logging endurance for different logging intervals are shown in Table 3.
Logging Interval
Memory Endurance
(minutes):
(Days):
1
7
5
35
10
70
15
30
105
210
60
420
TABLE 3: MEMORY ENDURANCE
NOTE!
In reality battery power may limit the deployment duration, not memory capacity.
The D-OptoLogger will operate until the battery voltage drops below around 7.0 volts. If this
occurs while the D-OptoLogger is in logging mode, the last set of data values in the data file will be
set to zero and the D-OptoLogger enters a low power sleep mode with no further data values
being logged.
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D-OptoLogger Operation Manual
Calibration
Under normal operating conditions the D-OptoLogger should require only infrequent calibration.
Calibration of the D-OptoLogger is a simple operation that can be performed in the field. Due to the
measurement principle of the D-OptoLogger, performing air calibrations is not advisable.
NOTE!
When calibrating the D-OptoLogger, do not allow water to enter into the instrument.
The offset and gain of the D-OptoLogger are calibrated individually. Normally only the offset will need
to be calibrated as the gain is more stable than the offset over time.
NOTE!
The gain should be calibrated only AFTER the offset has been calibrated.
FIGURE 7: D-OPTOLOGGER CALIBRATION WINDOW
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D-OptoLogger Operation Manual

Offset Calibration
A reference solution of 0% dissolved oxygen is required for the offset calibration. This can be created
by mixing a couple of teaspoons of sodium sulfite into 1 litre of distilled or fresh tap water.
Procedure:
1) Place the D-OptoLogger in the reference solution and allow it to equilibrate for at least 30
minutes.
2) Power up the D-OptoLogger and start D-OptoLog. Once the measurements have stabilized, press
the ‘Calibrate’ button in the main window.
3) Enter 0 (zero) in the offset calibration edit box and press the ‘Reset offset’ button.
4) The D-OptoLogger performs a calibration routine followed by a self-check; this can take up to 30
seconds. Do not remove the D-OptoLogger from the reference solution during this period. The
operator will be notified when the process is complete.

Gain Calibration
A solution of known dissolved oxygen content, other than 0%, should be used for the gain
calibration. The most practical method is to create a fully aerated solution. This can be done by
bubbling air through a container of distilled or fresh tap water, stirring frequently. After around 30
minutes, the water can be assumed to be fully saturated.
The actual dissolved oxygen saturation can be calculated by correcting for altitude, or preferably, the
local barometric pressure if that is known. The ‘Correction Calculator’ can be used to calculate the
corrected dissolved oxygen content of the fully aerated reference solution. As an example, if the
D-OptoLogger is installed at a field site at 435 meters above sea level, and a fully aerated reference
solution is prepared on site, the actual dissolved oxygen percent saturation is calculated at 95%. (See
Appendix 1)
Procedure:
1) Place the D-OptoLogger in the reference solution and allow it to equilibrate for at least 30
minutes.
2) Power up the D-OptoLogger and start D-OptoLog. Once the measurements have stabilized, press
the ‘Calibrate’ button in the main window to open the Calibration window.
3) Enter the pressure corrected dissolved oxygen percent saturation of the reference solution in the
gain calibration edit box and press the ‘Reset span’ button.
4) The D-Opto performs a calibration routine followed by a self-check; this can take up to 30
seconds. Do not remove the D-OptoLogger from the reference solution during this period. The
operator will be notified when the process is complete.
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D-OptoLogger Operation Manual
5. Maintenance
As with all instruments, it is good operating practice to make regular checks on the quality of data being
generated by the D-OptoLogger. This can be carried out on site using one of the following two methods:
1) Place a recently calibrated transportable dissolved oxygen sensor next to the D-OptoLogger and
compare the measurements. It is important to allow a sufficient period of time for temperature
equilibration to occur.
2) Place the D-OptoLogger in a solution of known dissolved oxygen content. A solution of 0% dissolved
oxygen saturation can be created by adding a few teaspoons of sodium sulfite to 1 litre of distilled or
fresh tap water.
The D-OptoLogger can tolerate some biofouling, however steps should be taken to minimize this where
possible. For example, covering the D-OptoLogger can reduce the amount of bio-growth by restricting
available light. The copper biofouling control ring should reduce bio-growth in the area around the
optical window; this ring is sacrificial and may require replacement on an occasional basis.
Periodically it may be necessary to clean the D-Opto optical window to remove bio-growth or other
accumulated deposits. Use warm soapy water to clean the D-OptoLogger.
NOTE!
DO NOT use a hard object to clean the optical window as this may scratch or damage it.
Only use the cleaning pads supplied with the D-Opto.
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D-OptoLogger Operation Manual
6. Troubleshooting
Interpreting the LED indicator
The LED indicator inside the D-OptoLogger housing, next to the battery and communication socket, can
be used to identify the D-OptoLogger’s current status. The interval between the flashing sequences may
be up to 8 seconds.
LED Blink Sequence:
Status Description:
One flash
Operational
Two flashes
Delayed start
Three flashes
Not operational, waiting for PC communications
Four flashes
Memory full
Five flashes
Low battery shut down
TABLE 4: LED FLASH SEQUENCE CODES
Loss of communication
If the PC starts to communicate with the D-OptoLogger, but then loses communication, replace the DOptoLogger battery.
If the D-OptoLogger is not communicating with the PC:
 Check the battery voltage.
 Check the communications cable is plugged into the correct serial port on the PC.
Zero value data
If the last data record in the data file consists of zero values the D-OptoLogger battery dropped below
around 7 volts and needs replacing.
Erratic dissolved oxygen readings
You may encounter occasions when the dissolved oxygen readings are highly erratic, but the
temperature readings are stable. The D-OptoLogger incorporates a high gain amplification circuit to
measure the fluorescence of the optical window. The instrument has been carefully designed to prevent
electrical interference impacting on the operation. Under extreme conditions however, noise may
become a problem.
 Track down the source of noise; this could be a nearby pump or other motor.
 If the D-OptoLogger is being bench tested in a small container of water, noise can be caused by a
lack of suitable earthing. Place a grounding wire from the water to the D-OptoLogger power
ground.
 The D-OptoLogger is supplied with built-in noise rejection specific for the country of supply. If
the D-OptoLogger is being used in a country other than the country it was supplied to, contact
your supplier or Zebra-Tech.
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D-OptoLogger Operation Manual
7. Appendices
Appendix 1: Pressure Correction Chart
Altitude
(m)
0
85
170
256
343
431
519
608
698
789
880
972
1066
1160
1254
1350
1447
1544
1643
1743
1843
1945
2047
2151
2256
2362
2469
2577
2687
2797
2909
3023
3137
Altitude
(feet)
0
278
558
841
1126
1413
1703
1995
2290
2587
2887
3190
3496
3804
4115
4430
4747
5067
5391
5717
6047
6381
6717
7058
7401
7749
8100
8455
8815
9178
9545
9917
10293
Barometric
pressure (mBar)
1013
1003
993
983
973
963
952
942
932
922
912
902
899
882
871
861
851
841
831
821
811
800
790
780
770
760
750
740
730
719
709
699
689
% Saturation
100
99
98
97
96
95
94
93
92
91
90
89
88
87
86
85
84
83
82
81
80
79
78
77
76
75
74
73
72
71
70
69
68
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D-OptoLogger Operation Manual
Appendix 2: Useful Conversions
Convert from
kPA
inHg
Feet
Centigrade
To
mBar
mBar
Meters
Fahrenheit
Calculation
Multiply by 10
Multiply by 33.85
Multiply by 0.3048
C) +32
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D-OptoLogger Operation Manual
8. Further Assistance
For further assistance with this or any other Zebra-Tech product, please contact:
Zebra-Tech Ltd
PO Box 1668
Nelson 7040
New Zealand
Tel: International 0064 3 548 0468
Fax: International 0064 3 548 0466
Email: [email protected]
For up to date information about the D-OptoLogger and other Zebra-Tech products, please visit the
Zebra-Tech Ltd website at:
http://www.zebra-tech.co.nz
Proudly designed and manufactured in New Zealand
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