PME miniDOT Manuale utente
Precision Measurement Engineering, Inc.
(760) 727-0300
www.pme.com
1
Precision Measurement Engineering, Inc. • www.pme.com
User’s Manual
2018
Precision Measurement Engineering, Inc.
(760) 727-0300
www.pme.com
2
Warranty
1-YEAR LIMITED WARRANTY ON miniDOT HARDWARE
Precision Measurement Engineering, Inc. (PME) warrant that the miniDOT Logger shall be
free of defects in workmanship and materials, under normal use, for a period of one year
from the date of shipment. This warranty is made only to the original purchaser. In the event
a miniDOT Logger covered by this warranty fails to operate according to our published
specifications, then return it freight pre-paid to PME or an authorized Service Provider. PME
will repair the unit at no charge to the customer and bear the cost of return shipment.
Carefully pack all components, as the customer is responsible for any freight damage.
This warranty does not apply to services or consumable / expendable items (such as
batteries, fuses and ropes) required for general maintenance. Equipment manufactured by
other companies (such as meteorology sensors, solar panels, etc) are warranted only to the
limit of the warranties provided by their original manufacturer.
PME makes no warranty, either expressed or implied, that the sensors will be operable after
they are exposed to adverse environmental conditions, such as bio-fouling, oil fouling,
freezing temperatures or others.
This warranty is void if, in our opinion, the miniDOT Logger has been damaged by accident,
mishandled, altered, or repaired by the customer, where such treatment has affected its
performance or reliability. In the event of such treatment by the customer, costs for repairs
plus two-way freight costs (no COD shipments will be accepted) will be borne by the
customer. In such cases, an estimate will be submitted for approval before repair work is
started. Items found to be defective should be returned to PME carefully packed, as the
customer will be responsible for freight damage.
Incidental or consequential damages or costs incurred as a result of the product malfunction
are not the responsibility of PME.
For all warranty or non-warranty returns please obtain, complete, and submit a RMA to PME.
This RMA form may be obtained at
http://www.pme.com/HTML%20Docs/RMAform.html.
After submission of this form, then PME will respond with a RMA number. Please place this
number on all shipments and related communications.
Precision Measurement Engineering, Inc.
(760) 727-0300
www.pme.com
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Safety Information
BURSTING HAZARD
Should water enter the miniDOT Logger and come into contact with the enclosed batteries,
then the batteries may generate gas, causing the internal pressure to increase. This gas will
likely exit via the same location where the water entered, but not necessarily. The miniDOT
Logger is designed to release internal pressure, as the black end cap is unscrewed, prior to
the disengagement of the black end cap threads. If internal pressure is suspected, then treat
the miniDOT Logger with extreme caution.
Revision History
Date Revision Description
2014JUN09 Initial Document, revised from 6881
2014JUL01 Extensively Revised
2014JUL16 Added Storage When Not in Use to sec 1.2
2014SEP24 Added pictures, reworded. Removed wire mesh installation instructions
2014NOV14 Added update Java instructions. Removed statement saying alkaline batteries
supplied.
2014DEC17 Added 1 green flash for sample intervals of 1 minute or less
2015JAN09 Minor revision
2015JAN23 Added note about miniDOTPlot large sample sets
2015FEB03 Modified battery endurance, modified wording, added # files warning
2015APR15 Added file upload to Android phone instructions
2015SEP11 Added the Cu mesh / plate instructions
2015SEP11 Updated wording to be consistent throughout manual
2016APR13 Expanded description of Android use
2017FEB28 Revised recalibration recommendation from 1/2 million samples to yearly.
2018JAN08 Corrected "oxygen saturation" to be "air saturation"
2018JAN25 Changed wording
2018MAR29 Updated for 16GB SD cards, added maintenance section, changed battery
section
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CONTENTS
Chapter 1 Quick Start
1.1 The Quickest Start Possible
1.2 A Few Details
1.3 Overview General Maintenance
Chapter 2 Software
2.1 Overview and Software Installation
2.2 miniDOTControl
2.3 miniDOTPlot
2.4 miniDOTConcatenate
Chapter 3 miniDOT Logger
3.1 Overview
3.2 Opening and Closing the miniDOT
Logger
3.3 Electrical Connections and Controls
3.4 Battery Replacement
3.5 Installing Copper Mesh or Plate
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Chapter 1: Quick Start
1.1 The Quickest Start Possible
Your miniDOT Logger has arrived completely ready to go. It is set to measure and record
time, battery voltage, temperature, oxygen concentration, and measurement quality once
every 10 minutes and write one file of measurements daily. Open the miniDOT Logger and
move the Logger Control Switch to the “Record” position. In this condition, the miniDOT
Logger will record measurements for a year before the internal batteries are expended. You
must re-close the miniDOT Logger prior to deploying it.
At the end of the deployment period, open the miniDOT Logger and connect it to a HOST
computer via the USB connection. The miniDOT Logger will appear as a ‘thumb drive’. Your
temperature and oxygen concentration measurements, together with a time stamp indicating
the time the measurements were made, are recorded in text files in the folder having the
serial number of your miniDOT Logger. These files can be copied onto any Windows or Mac
HOST computer.
This Manual and other software programs are also recorded on the miniDOT Logger.
miniDOTControl program allows you to see the state of the miniDOT Logger as well as
set the recording interval.
miniDOTPlot program allows you to see the plots of the recorded measurements.
miniDOTConcatenate program gathers all the daily files into one CAT.txt file.
Your miniDOT Logger will return to recording measurements after you disconnect the USB
connection. If you wish to stop recording, then move the Logger Control Switch to the “Halt”
position.
You may move the Logger Control Switch at any time.
Follow these steps to start the deployment, logging DO & T once each 10 minutes:
1) Open the miniDOT Logger by unscrewing the white pressure housing from the black end
cap. It opens like a flashlight. Remove the white pressure housing completely. Inside
you will see the circuit pictured below:
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2) Move the Logger Control Switch
to the “Record” position. The LED will flash green 5
times. The miniDOT Logger will now record a measurement of time, battery voltage,
temperature, and dissolved oxygen every 10 minutes (or at some other interval you may
have set using the miniDOTControl program).
3) Inspect the o-ring seal for debris.
4) Close the miniDOT Logger by screwing the white pressure housing back onto the black
end cap.
5) Deploy the miniDOT Logger.
Follow these steps to end the deployment
1) Recover the miniDOT Logger
2) Clean and dry all accessible surfaces except the ‘sensing foil’.
3) Open the miniDOT Logger by unscrewing the white pressure housing from the black end
cap. Remove the white pressure housing completely, taking care that water does not drip
onto interior surfaces of circuits or other items inside the miniDOT Logger.
4) Connect to a Windows HOST computer via the USB connection. The miniDOT Logger
will appear as a ‘thumb drive’.
5) Copy the folder having the same serial number as the miniDOT Logger (example 7450-
0001) to the HOST computer.
6) (Suggested, but optional) Delete the measurement folder, but NOT the miniDOTControl
program or the other .jar programs.
7) (Optional) Run the miniDOTControl program to see the state of the miniDOT Logger such
as battery voltage or to select a different recording interval.
8) (Optional) Run the miniDOTPLOT program to see a plot of measurements.
9) (Optional) Run the miniDOTConcatenate program to gather together all the daily files of
measurements into one CAT.txt file.
10) If no more recording is desired, then move the Logger Control Switch to “Halt”, otherwise
leave it set to “Record” to continue recording measurements.
11) Disconnect the miniDOT Logger from the USB connection.
12) Inspect the o-ring seal for debris.
13) Close the miniDOT Logger by screwing the white pressure housing back onto the black
end cap.
Remove the batteries if storing the miniDOT Logger for extended periods.
1.2 A Few Details
The previous section gives instructions for sampling at 10-minute intervals. However, there
are a few additional details that will enhance use of the miniDOT Logger.
Recording Interval – The miniDOT Logger measures and records time, battery voltage,
temperature, dissolved oxygen concentration and measurement quality at equal time
intervals. The default time interval is 10 minutes. However, it is also possible to instruct the
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miniDOT Logger to record at different intervals. This is accomplished by running the
miniDOTControl.jar program supplied with the miniDOT Logger. Recording intervals must
be 1 or more minutes and must be less than or equal to 60 minutes. Intervals outside this
range will be rejected by the miniDOTControl program. (Contact PME for other recording
intervals.)
Please refer to Chapter 2 for instructions on operating the miniDOTControl program.
Time – All miniDOT Logger times are UTC (formerly known as Greenwich mean time
(GMT)). The miniDOT Logger internal clock will drift in the <10 ppm range (< about 30
seconds/month) so you should plan to connect it occasionally to a HOST computer having an
Internet connection. The miniDOTControl program will automatically set time based on an
Internet time server.
Please refer to Chapter 2 for instructions on operating the miniDOTControl program.
File Information – The miniDOT Logger software creates 1 file daily on the miniDOT
Logger’s internal SD card. The number of measurements in each file will depend upon the
sample interval. Files are named by the time of the first measurement within the file based
on the miniDOT Logger’s internal clock and expressed in YYYY-MM-DD HHMMSSZ.txt
format. For example a file having the first measurement on September 9, 2014 at 17:39:00
UTC will be named
2014-09-09 173900Z.txt.
Files can be uploaded from the miniDOT Logger by connecting it to a HOST computer. Use
the HOST computer’s copy/paste functions to move the files from the miniDOT Logger to the
HOST computer.
Each measurement within the files has a time stamp. The time stamp format is Unix Epoch
1970, the number of seconds that have passed since the first moment of 1970. This may be
inconvenient in some cases. If so, then the miniDOTConcatenate program not only
concatenates all the measurement files, but also adds more readable statements of the time
stamp.
Please refer to Chapter 2 for instructions on operating the miniDOTConcatenate program.
The miniDOT Logger requires time and battery energy to work through the file directory on
the SD card to allocate new file space. A few hundred files on the SD card is not a problem,
but as the number of files grows large into the thousands then the miniDOT Logger may
suffer decreased battery life or other performance problems. Please, at the earliest
convenient time, copy the recorded files to a HOST computer and delete them from miniDOT
Logger’s SD card. Also, do not use miniDOT Logger to store files unrelated to the miniDOT
Logger’s operation.
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Control miniDOT and Upload Files to an Android device – It is possible to control
miniDOT and to transfer your measurement files from the miniDOT Logger to your Android
device. This operation has 3 prerequisites.
1. An Android device equipped with USB On-The-Go (OTG) feature and one that can act as
a USB host. OTG is a feature for most modern Android devices that allow them to act as
a USB host. OTG was introduced with Android version 3.1 and should be a useable
feature for most devices. It is still possible that your device doesn't support OTG or that it
does support OTG but will either not see miniDOT as a local drive or will not control
miniDOT. Please test your device with a miniDOT Logger prior to attempting to upload
while in the field.
2. A USB OTG cable. This is essentially an adapter with a micro USB connector on one end
that connects to your Android device and a standard A type USB plug on the other. The
cable supplied with the miniDOT Logger connects to this end.
3. A "File Explorer" app downloaded on your Android device. These types of apps assist
with being able to view and move files from device to device. "ES File Explorer" is a free
app available on the Google app store and is recommended for use with the miniDOT
Logger. Samsung products have their own file explorer called "MyFiles".
If the 3 requirements are met, then connect the miniDOT Logger to your Android device. You
should see the miniDOT Logger’s green connection light come on and your Android device
will display a message about "preparing USB storage". When "USB storage ready" is shown,
then use your "file explorer" program to move your data from the miniDOT Logger onto your
Android device. You will later use the device to move the file to a new location via internet or
possibly move the file onto plugged SD card storage.
miniDOT can be controlled by using a PME app. This can be downloaded from Google Play
Store. Search for "pmecontrolapp". Download. The app is free. After the app is
downloaded just plug miniDOT into the device. This will bring up the app. There may be
some confusion at plug in time since the app comes up but also the system file explorer may
appear. The app will appear requesting a sample interval be entered. If not entering an
interval touch Done to make the entry pad disappear. The app will scold you for not entering
a valid sample interval. Ignore this. The sample interval within miniDOT will be unchanged
and appears in the app.
Again, it is highly recommended that you try these operations prior to depending upon this in
the field. Not all devices that support OTG will communicate with miniDOT.
Currently the associated miniDOT Logger programs miniDOTPlot, and miniDOTConcatenate
are not supported on the Android devices.
1.3 Overview General Maintenance
Cleaning the Sensing Foil –The sensing foil can be cleaned at regular intervals depending
on the fouling condition at the site. The cleaning procedure of the sensing foil should be done
with caution so that the protective coating is not removed. If the fouling is calcareous it can
normally be dissolved with household vinegar.
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If the marine growth remains, then use Q-tips to gently wipe the sensing foil after it has been
softened by soaking in vinegar or perhaps diluted HCl. After cleaning the sensing foil, then it
should be rinsed well in clean tap water before storing or reuse. Do not use other organic
solvents such as acetone, chloroform, and toluene since these and others will damage the
sensing foil.
The sensing foil can also be cleaned using a 3% H2O2 solution or rinsing it with ethanol.
The white pressure housing and black end cap can be gently scrubbed.
AA Alkaline Battery Life – Alkaline batteries will give somewhat less performance than
lithium, especially at low temperatures. Alkaline batteries are superior to lithium in one way:
you can determine how much battery life remains by measuring the battery terminal voltage.
For short deployments of a month or two, then alkaline batteries will provide adequate
performance. For longer deployments, or for deployments in cold environments, then
substitute lithium batteries.
AA Lithium Battery Life – The miniDOT Logger consumes battery power mostly from the
measurement of dissolved oxygen, but also slightly from simply keeping track of time, writing
files, sleeping, and other activities. The following table shows the approximate endurance of
the miniDOT Logger when powered by the Energizer L91 AA lithium / ferrous disulfide
batteries:
SAMPLE INTERVAL
(minutes)
Main AA Battery Life
(months)
Number of Samples
1 12 500K
10 >12 >52,000
60 >12 >8,000
Keep a general record of the miniDOT Logger’s number of samples. It is not possible to
accurately tell the charge state of a lithium battery by measuring its terminal voltage. If you
have a general idea of the number of samples already obtained on a battery, then you can
make a guess as to how many more samples remain.
The numbers in the table above are, at the time of this writing, based upon extrapolations of
testing of 500K samples acquired at a 5-second interval. The 1-year performance at 1
minute is very likely. Performance at longer sample intervals will be much longer, but how
long is difficult to predict. In any event, these AA batteries are easily available and relatively
inexpensive compared to the cost of the miniDOT Logger. PME suggests you replace the
batteries often, especially before any long (months) measurement deployments.
Monitor battery voltage in the miniDOTControl program. You cannot tell from terminal
voltage of a lithium battery how long the battery will last, but you can tell if it will die soon.
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The Low Drain Performance plot below gives an estimate of terminal voltage for both lithium
and alkaline batteries. You can operate batteries down to about 2.4 Volts (for two in series,
1.2 Volts on the graph below). Remove the batteries and measure each of them. If your
combined battery voltage is less than 2.4 Volts, replace the batteries.
You may also use alkaline AA batteries such as Duracell Coppertop. They will not last nearly
as long, especially at low temperatures, but will likely be adequate for several weeks at 10-
minute interval.
When replacing batteries use only fresh batteries. Don’t mix battery types. If one battery
differs in type or charge level from the other and the miniDOT Logger runs them to full
discharge, then one battery may leak. SEE SECTION 3.4 FOR CAUTION ON BATTERY
PLACEMENT.
Err on the side of caution when planning your deployment.
The recommended battery is the Energizer L91 lithium battery. For more information
including the performance at low temperatures, then click the link:
http://data.energizer.com/PDFs/l91.pdf
The figure below gives a general idea of terminal voltage vs. lifetime. Service life in hours is
incorrect since miniDOT Logger draws far less than 50 mA continuously, but the general
shape of the voltage vs. time gives an estimate of life remaining. This plot is taken from the
manufacturer’s specification. The plot is for a single battery. Double the voltages shown to
give the terminal voltage as measured in the picture above. The miniDOT Logger halts
operation at a total of 2.4 Volts.
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