EUTECH INSTRUMENTS DO 700 - REV 3 User manual

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Instruction Manual
DO 700 Dissolved Oxygen/ºC/ºF
Bench Meter
Part of Thermo Fisher Scientific 68X541703 Rev.3 . Nov 2010

TABLE OF CONTENTS
1. INTRODUCTION.............................................................. 1
2. GETTING STARTED........................................................ 2
2.1 Keypad Functions ...................................................................2
2.2 LCD Annunciators...................................................................3
2.3 Meter Connections..................................................................3
3. DISSOLVED OXYGEN / ATC ELECTRODE................... 4
4. CALIBRATION................................................................. 5
4.1 Temperature Calibration .........................................................6
4.2 % Saturation Calibration .........................................................7
4.3 100% Calibration.....................................................................7
4.4 0% Calibration.........................................................................7
4.5 mg/L or ppm (Concentration) Calibration................................8
5. SETUP FUNCTIONS........................................................ 9
5.1 1.0 CAL (Calibration)...............................................................9
5.2 2.0 ELE (Electrode Information)..............................................10
5.3 3.0 ConF (Configuration).........................................................10
5.4 3.1 rdY (Ready Stability Indicator / Auto Hold)........................10
5.5 3.2 ºC ºF (Celsius or Fahrenheit) ............................................10
5.6 3.3 dPr (Barometric Pressure Adjustment)..............................11
5.7 3.4 SALt (Salinity Adjustment) ................................................11
5.8 3.5 OFS (Offset Adjustment) from % mode.............................11
5.9 3.5 Unit (Unit Adjustment) from concentration mode...............12
5.10 4.0 rSt (Reset).........................................................................12
5.11 5.0 CLr (Clear Stored Memory)...............................................12
6. TAKING MEASUREMENTS ............................................ 13
6.1 HOLD Function .......................................................................14
6.2 Storing and Recalling Data .....................................................14
7. ELECTRODE MAINTENANCE........................................ 15
8. DISSOLVED OXYGEN THEORY .................................... 18

9. REPLACEMENTS AND ACCESSORIES........................ 22
10. TROUBLESHOOTING GUIDE......................................... 23
11. SPECIFICATIONS............................................................ 25
12. WARRANTY..................................................................... 26
13. RETURN OF ITEMS......................................................... 27

1
1. INTRODUCTION
Thank you for purchasing our DO 700 series benchtop meter.
This microprocessor-based meter is economical and simple to
use. The design incorporates a large LCD for clear viewing, yet
offers a small footprint to conserve space.
The DO 700 measures Dissolved Oxygen in % saturation or
concentration (mg/L or ppm) with temperature (ºC or ºF).
Each meter includes a convenient slide-out card for quick
reference. Also included is an electrode arm and metal bracket
which can be easily attached to the left or right side of the meter
according to your preference.
We take great pride in every instrument we manufacture
and hope this one serves you well.

2
2. GETTING STARTED
2.1 Keypad Functions
Powers the meter on and off. Upon power on, the meter
automatically begins in the mode that was last used.
Calibration and memory values are retained even if meter
is unplugged.
Toggle between available measurement modes—%
saturation or concentration (mg/L or ppm). Also used to
switch to Temperature calibration during DO calibration
modes.
Press and hold for 5 seconds to enter SETUP mode.
Toggles between measurement and calibration modes.
In SETUP mode, returns user to the measurement mode.
Confirms calibration values in CAL mode.
Confirms selections in SETUP mode.
View recalled values in memory mode.
SIncrease value. Scroll up in SETUP & CAL modes.
MI (Memory Insert) stores values into memory.
MR (Memory Recall) recalls values from memory.
TDecrease value. Scroll down in SETUP & CAL modes.
Freezes measured reading. Press again to resume
live reading.

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2.2 LCD Annunciators
2.3 Meter Connections
DC Power supply
ATC Temperature connection of Dissolved Oxygen electrode
DO BNC connection of Dissolved Oxygen electrode

4
3. DISSOLVED OXYGEN / ATC ELECTRODE
The DO 700 includes a galvanic DO
electrode with built in temperature
measurement.
The electrode has a dual cable; a BNC
connector for DO measurement and a mini-
phono plug for temperature. The electrode is
pre-filled with electrolyte that is separated
from the sample by an oxygen permeable
membrane. The membrane is pre-assembled
for you and fixed to a detachable cap. The
pre-assembled cap design allows simple
replacement and fast conditioning.
The electrode is light-weight with a 12-mm
body diameter and a 16-mm tip diameter
from at the detachable Noryl cap. The
compact sensing area reduces air
entrapment resulting in quick, accurate, and
stable readings.
Provide simple stirring for best results—
ideally achieve a minimum water flow rate of
2 inch/second on the membrane.
The probe is not recommended for samples
beyond 0 to 50 °C.
The membrane is thin and can be replaced if damaged. Use care to
protect from scratches, abrasion, or contact with solids. For best
results keep membrane clean by rinsing after daily use. See Section 7
– Electrode Maintenance.

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4. CALIBRATION
The DO 700 has three measurement modes; DO as % saturation, DO
as mg/L (or ppm) concentration, and temperature.
Dissolved oxygen levels vary with temperature, barometric pressure,
and salinity, so calibration must be performed with consideration of
these factors. It is necessary to set the proper temperature,
barometric pressure and salinity values prior to performing any
DO calibration or measurement.
See Section 4.1 — Temperature Calibration.
See Section 5.6 — Barometric Pressure Adjustment.
See Section 5.7 — Salinity Adjustment.
The DO 700 will accept two % saturation calibration points; 100%
using saturated air or air-saturated water, and 0% using zero oxygen
solution. When 100% or 0% calibration is performed, the concentration
value is adjusted accordingly. Therefore, it is not necessary to calibrate
the concentration mode. If calibrating for 0% oxygen, note that the
meter will take several minutes to reach 0% saturation value and
constant stirring is not required.
The following table lists calibration values in % saturation calibration
mode with two different barometric pressures. Note that the saturation
value (92.1%) has decreased due to the lower barometric pressure
entered.
% Saturation
(of factory default value) Calibration Value (760mmHg) Calibration Value (700mmHg)
less than 10% 0% 0%
10.1% to 49.9% CAL ERR CAL ERR
50% to 150% 100% 92.1%
If calibration is attempted from 10.1% to 49.9%, CAL Err message is
shown—calibration is rejected and the display will return to calibration
mode.

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The DO 700 will accept one calibration point in concentration mode.
The minimum value is 2 mg/L (ppm), and the calibration window is +/-
40% of the factory default value.
Temperature and % saturation calibration should take place before
attempting to perform mg/L (ppm) concentration calibration.
Calibration of the concentration mode will only replace the previous
concentration calibration and does not affect the % saturation
calibration.
To offset your % saturation reading to match another instrument, see
Section 5.8 – Offset Adjustment.
Perform daily calibration for best results. New calibration values will
automatically override the existing data. To completely recalibrate the
meter and when installing a replacement electrode, it is best to clear all
calibration data. See Section 5.10 – Reset.
4.1 Temperature Calibration
For best DO accuracy, ensure that the temperature is accurate. The
thermistor sensor used for automatic temperature compensation and
measurement is accurate and stable, so frequent calibration isn’t
required. Temperature calibration is recommended upon probe
replacement, whenever the temperature reading is suspect, or if
matching against a certified thermometer is desired.
The DO 700 will default to 25 ºC / 77 ºF when the ATC plug is not
connected.
1) Place the probe into a solution with a known accurate temperature
such as a constant temperature bath.
2) Press followed by . The primary display shows the
measured temperature while the secondary display shows the
factory default temperature.
4) Adjust the temperature using or . Press to accept or
to cancel. The meter allows an adjustable maximum value of ±
5ºC (or ± 9ºF) from the factory default temperature.

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4.2 % Saturation Calibration
The DO700 can be easily calibrated in air. For best accuracy, ensure
that the barometric pressure value is accurate.
The barometric pressure factory default is 760 mm Hg (1.013 bar),
which results in a theoretical calibration value of 100% saturation in air.
If the barometric pressure setting has been changed from 760 mm Hg,
the meter will automatically adjust to a new % saturation calibration
value instead of 100%. This new value is correct for the adjusted
barometric pressure.
4.3 100% Calibration
1) Rinse the probe well with clean water (do not dry).
2) Press to select % saturation.
3) Hold the probe in the air with the tip facing downwards. Wait for
the reading to stabilize.
4) Press . The CAL indicator will blink and secondary display will
indicate the calibration point, 100.0.
5) Press to confirm the calibration. The primary display will blink
briefly before calibrating to 100.0%.
6) Press to return to measurement mode, or continue with 0%
calibration if desired.
4.4 0% Calibration
1) Rinse the probe well with clean water (do not dry).
2) Press to select % saturation.
3) Submerse probe in zero oxygen calibration solution and stir
slowly. Wait for the reading to stabilize—this can often take
more than 10 minutes!

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4) Press . The CAL indicator will blink and the secondary display
will indicate the calibration point, 0.0.
5) Press to confirm the calibration. The primary display will blink
briefly before calibrating to 0.0%.
6) Press to return to measurement mode, or continue with 100%
calibration if desired (note 0% calibration followed by 100%
calibration is not recommended---always perform 100% calibration
first).
4.5 mg/L or ppm (Concentration) Calibration
Performing a saturation calibration at 100% or 0% will simultaneously
calibrate the corresponding mg/L (ppm) concentration value.
Therefore, additional mg/L (ppm) calibration isn’t required in most
circumstances.
If desired, you can perform a calibration adjustment in mg/L (ppm)
without affecting your % saturation calibration value.
1) Rinse the probe well with clean water (do not dry).
2) Press to select concentration mg/L (ppm).
3) Dip the probe into a sample of known oxygen concentration (i.e.
determined by titration or another instrument). Wait for the reading
to stabilize.
4) Press . The CAL indicator and current concentration display
briefly, before CAL flashes. The concentration value based on the
factory default calibration is shown.
5) Press or to adjust the reading to match the known
oxygen concentration value.

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6) Press to confirm the calibration. The primary display will blink
briefly before returning to measurement mode.
NOTE: The minimum calibration value is 2 mg/L. In addition, the
calibration is limited to ±40% adjustment of the factory default value to
prevent erroneous calibrations.
5. SETUP FUNCTIONS
Use the setup feature to customize your instrument operation.
There are two setup menus; one menu is derived from the %
saturation mode and the other from the mg/L (or ppm) concentration
mode.
First, select the appropriate measurement mode you wish to adjust by
pressing until the desired units are displayed. During
measurement, press and hold for 5 seconds to enter SETUP
mode of the parameter being measured.
Press or to change programs or change options.
Press to select the program or confirm selection.
Press to go back one level or return to measurement mode.
5.1 1.0 CAL (Calibration)
Press to view stored calibration points.
Note: % saturation mode will list two points, while
concentration mode has only one point.

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5.2 2.0 ELE (Electrode Information)
Press to view calibration factor (CAL.F)
TIP: The factor is an indication of the probe’s efficiency. It is
the ratio of the actual mV produced by the probe to the
theoretical mV value. The ratio displays from 0.5 to 1.999.
Press to view mV output for 100% (HI).
Press to view mV output for 0% (LO).
Press to view Offset % (OFS)—% saturation mode only.
5.3 3.0 ConF (Configuration)
Press to access set-up programs 3.1 thru 3.5.
5.4 3.1 rdY (Ready Stability Indicator / Auto Hold)
Press .
Press or to choose READY “On”, READY “OFF”, or
Auto HOLd.
Press to confirm.
5.5 3.2 ºC ºF (Celsius or Fahrenheit)
Press .
Press or to select ºC or ºF.
Press to confirm.

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5.6 3.3 dPr (Barometric Pressure Adjustment)
Press .
Press or to select units; Hg (mm Mercury) or bAr.
Press to confirm.
Press or to adjust the value, press to accept.
5.7 3.4 SALt (Salinity Adjustment)
For best accuracy, enter the actual salinity value if your samples are at
least 0.1 ppt (100 ppm). Maximum adjustment is 50 ppt (50,000 ppm or
5% salt).
Press .
Press or to adjust the value (in parts per thousand).
Tip: 0.1 ppt = 100 ppm salinity
Press to confirm.
5.8 3.5 OFS (Offset Adjustment) from % mode
Use this feature to offset the meter’s value to another DO meter.
Using the % saturation mode, observe the reading a sample solution
after it has stabilized. Similarly, observe the reading of the same
sample using another DO meter as a reference. The probe of the
reference meter should be immersed in the same sample at the same
depth.
The DO 700 allows +/- 10.0% offset adjustment. Note that subsequent
user calibrations will reset the offset adjustment back to the factory
default value of 0.0 %.
Press .
Press or to adjust the % offset.

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Press to confirm.
5.9 3.5 Unit (Unit Adjustment) from concentration mode
Press .
Press or to select ppm or mg/L units.
Press to confirm.
5.10 4.0 rSt (Reset)
Press .
Press or to select “Yes” (Reset) or “No” (Cancel).
If “Yes”, press or to select “Cal” (calibration reset
only) or “FCt” (complete reset to factory default settings).
Press to confirm.
5.11 5.0 CLr (Clear Stored Memory)
Press .
Press or to select “Yes” (Erase memory) or “No”.
Press to confirm.

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6. TAKING MEASUREMENTS
During measurement the dissolved oxygen reading is
automatically compensated for pressure and salinity. For best
accuracy, ensure the pressure and salinity settings are adjusted
accordingly from the setup menu. The factory default value for
barometric pressure is 760 mm Hg or 101.3 bar (sea level). The
factory default value for salinity is 0.0 ppt (no salinity).
See Section 5.6 — Barometric Pressure Adjustment.
See Section 5.7 — Salinity Adjustment.
Press to select the desired measurement mode:
•Percentage Saturation (%) and Temp (º C or ºF)
•Concentration (mg/L or ppm) and Temp (º C or ºF)
Follow these general rules when taking measurements:
•Keep the membrane free from contact with solid
objects.
•Provide stirring of your solution⎯this helps to overcome
oxygen consumption of the probe and prevents air
bubble entrapment.
•Do not submerge the cable for extended periods.
•Use with aqueous solutions only.
•The pre-assembled cap must be completely submersed
to obtain an accurate reading in solutions.
•Rinse the probe well with DI water or rinse solution
between measurements.

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6.1 HOLD Function
For prolonged observation of a reading, press during
measurement mode to freeze the display. The “HOLD” indicator will
display when the reading is held. To release the held value and
resume measurement, press again or insert the held value into
memory by pressing .
6.2 Storing and Recalling Data
The DO 700 can retain up to 100 data points into memory for
later retrieval.
1) In the measurement mode, press to insert the measured value
into memory. The stored memory location value (StO) is briefly
displayed.
2) To recall data from memory, press . The location of the most
recent stored data is displayed first. Press or to select the
location of the desired data, then press to accept.
3) Press to return to the stored data location. Press to return
to measurement mode. To erase stored data, see Section 5.11 —
Clear Stored Memory.

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7. ELECTRODE MAINTENANCE
The DO 700 electrode produces an output proportional to the oxygen
present in the medium in which it is placed. The galvanic probe design
allows for immediate use—unlike the typical 15 minute warm-up period
required for polargraphic electrodes.
The probe consists of two parts. The upper part consists of the anode,
cathode, and dual cable. The lower part consists of a pre-assembled
cap, and electrolyte solution.
Oxygen diffuses through the membrane onto the cathode, where it is
consumed. This process produces an electrical current which flows
through the cable to the meter. The electric current produced is
proportional to the oxygen that passes through the membrane and the
layer of electrolyte. This makes it possible to measure the partial
pressure of oxygen in the sample at a given temperature.
Since the DO in the sample is consumed by the cathode it is essential
to have flow past the membrane of the probe to prevent the occurrence
of false readings. The probe uses very little oxygen for its
measurement. This enables it to function correctly with liquid
movement as low as 2 inch/sec across membrane.
The permeability of the membrane to oxygen varies greatly with
temperature. Therefore compensation is needed for this variation. The
DO 700 probe comes with built-in temperature compensation for the
membrane variation.
Proper maintenance will help you maximize probe life and achieve
most accurate readings.
Deposits on the membrane surface act as a barrier to oxygen diffusing
through the membrane, so clean the membrane to assure maximum
reliability. After each use, rinse the probe with clean water to avoid any
hardening of deposits or bacterial growth.
NOTE: Although the membrane is strong and not easily damaged,
wipe it gently while cleaning it. If the membrane is punctured,
damaged, or torn, the probe will not function properly.

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There are no special probe storage requirements.
Cap and Electrolyte Replacement
Replacement of the pre-assembled cap is required only when you
cannot calibrate the probe, or if the membrane is damaged. Typical
membrane damages are punctures or wrinkles caused during
measurements or cleaning.
1) Unscrew the cap counter clockwise from the probe sensing tip.
2) Rinse the probe under running water.
3) Mount the nozzle tip onto the syringe provided. Fill the syringe
with the refill solution through the tip of the plastic bottle.
4) Hold the probe upside down. Insert the nozzle tip into one of the 4
holes surrounding the silver cathode. Inject the fill solution into the
probe body until solution leaks out from the fill hole (approximately
5 mL).
5) Replace pre-assembled cap by tightening clockwise until hand
tightened.
6) Allow at least 1 hour for the electrode to equilibrate before
usage.