Delta OHM HD2109.1 User manual



Operating manual
Dissolved oxygen meters /
thermometers
HD2109.1 – HD2109.2
www.deltaohm.com
Companies / Brands of GHM
English
Keep for future reference.

HD2109 - 2 - V2.4
CONTENTS
INTRODUCTION..................................................................................................................................................... 3
KEYBOARD AND MENU DESCRIPTION ............................................................................................................ 8
MEASUREMENT OF THE DISSOLVED OXYGEN ............................................................................................14
How to measure ................................................................................................................................................14
Measurement of the concentration of dissolved oxygen......................................................................................15
Electrolyte solution and/or membrane replacement ............................................................................................15
Check the probe's status ....................................................................................................................................18
Control the zero of the probe .............................................................................................................................18
Dissolved oxygen probe storage ........................................................................................................................18
Polarographic probe and galvanic probe: differences..........................................................................................19
Firmware update for DO9709SM and DO9709SG probes ..................................................................................19
Pt100 TEMPERATURE PROBE ...................................................................................................................................20
How to measure ................................................................................................................................................20
Instructions to connect the TP47 module for 4-wire Pt100 probes ......................................................................20
Direct connection of 4-wire Pt100 sensor to a DIN45326 connector ...................................................................21
WARNINGS AND OPERATING INSTRUCTIONS..............................................................................................22
INSTRUMENT SIGNALS AND FAULTS..............................................................................................................23
LOW BATTERY WARNING AND BATTERY REPLACEMENT.......................................................................25
INSTRUMENT STORAGE.....................................................................................................................................26
SERIAL INTERFACE AND USB ...........................................................................................................................27
STORING AND TRANSFERRING DATA TO A PERSONAL COMPUTER......................................................29
THE LOGGING FUNCTION -ONLY FOR HD2109.2......................................................................................................29
CLEARING THE MEMORY -ONLY FOR HD2109.2 ......................................................................................................29
THE PRINT FUNCTION ............................................................................................................................................30
CONNECTION TO A PC........................................................................................................................................31
CONNECTION TO THE RS232C SERIAL PORT OF THE INSTRUMENT.............................................................................31
CONNECTION TO THE USB 2.0 PORT OF THE INSTRUMENT -ONLY FOR HD2109.2......................................................31
NOTES ABOUT WORKING AND OPERATIVE SAFETY..................................................................................32
INSTRUMENT TECHNICAL CHARACTERISTICS...........................................................................................33
TECHNICAL DATA OF PROBES ........................................................................................................................35
DISSOLVED OXYGEN PROBES ..............................................................................................................................35
TEMPERATURE PROBES Pt100 SENSOR USING SICRAM MODULE ............................................................................37
4-WIRE Pt100 PROBES WITH TP47 MODULE .........................................................................................................37
ORDER CODES ......................................................................................................................................................38
WARRANTY...............................................................................................................................................................39

HD2109 - 3 - V2.4
INTRODUCTION
The HD2109.1 and HD2109.2 are portable instruments with a large LCD display. They measure the
concentration of dissolved oxygen in liquids (in mg/l), the saturation index (in %) and the tem-
perature using SICRAM combined probes of polarographic, with two or three electrodes, and
galvanic type with integrated temperature sensor. Temperature only is measured by Pt100 -
SICRAM or direct 4 wires - immersion, penetration or contact probes.
Thanks to an internal pressure sensor, the instruments automatically compensate for barometric
pressure. The instrument anticipates automatic compensation of the oxygen probe membrane per-
meability and of the salinity of the liquid being examined.
The dissolved oxygen probe's quick calibration function guarantees timely correctness of the per-
formed measurements.
The dissolved oxygen and temperature probes are fitted with an automatic detection module, with
the factory calibration settings already being memorized inside.
The HD2109.2 is a datalogger. It memorizes up to 18,000 dissolved oxygen concentration, satura-
tion index measurements, barometric pressure and temperature samples which can be transferred
from the instrument connected to a PC via the RS232C serial port or USB 2.0 port. The storing in-
terval, printing, and baud rate can be configured using the menu.
The HD2109.1 and HD2109.2 models are fitted with an RS232C serial port and can transfer the ac-
quired measurements to a PC or to a portable printer in real time.
Printing and, for the model HD2109.2, logging always include the temperature, in °C or °F, the
concentration of dissolved oxygen in liquids (in mg/l), the saturation index (in %) and the baromet-
ric pressure (in mbar).
The Max, Min and Avg function calculates the maximum, minimum or average values.
Other functions include: the relative measurement REL, the Auto-HOLD function, and the auto-
matic turning off which can also be disabled.
The instruments have IP66 protection degree.
This manual describes the HD2109.1 and HD2109.2 models: if not otherwise specified, the de-
scription is intended to be applicable to both models.

HD2109 - 4 - V2.4
Dissolved Oxygen – Temperature
HD2109.1

HD2109 - 5 - V2.4
HD2109.1
1. 8-pole DIN45326 connector, input for dissolved oxygen and temperature combined probes,
for Pt100 SICRAM temperature probes and direct 4-wire Pt100 probes complete with TP47
module.
2. External auxiliary power supply connector input (positive at centre).
3. Battery symbol: displays the battery charge level.
4. Function indicators.
5. Secondary display line.
6. CAL/key: during normal operation starts the dissolved oxygen probe calibration; in the
menu, increases the current value.
7. FUNC/ENTER key: during normal operation displays the maximum (MAX), the minimum
(MIN) and the average (AVG) of current measurements; in the menu, confirms the current
selection. This updates the display measurement when the Auto-Hold function is enabled.
8. REL/key: enables the relative measurement (displays the difference between the current
value and the logged value when the key is pressed); in the menu, decreases the current
value.
9. SERIAL key: starts and ends the data transfer to the serial communication port.
10. MENU key: allows access to and exit from the menu.
11. mg/l-%-ESC key: cyclically changes the main variable measurement between:
•dissolved oxygen concentration (in mg/l),
•saturation index (in %),
•barometric pressure (in mbar).
In the menu, cancels the operation in progress without making changes.
12. °C/°F key: when the probe is not connected, allows manual modification of the temperature.
When a probe with temperature sensor is connected, pressing this key twice changes the unit
of measurement from degrees Celsius to Fahrenheit.
13. ON-OFF/AUTO-OFF key: turns the instrument on and off; when pressed together with the
CAL key, disables the automatic turn off.
14. MAX, MIN and AVG symbols.
15. Main display line.
16. Line for symbols and comments.
17. 8-pole MiniDin connector for RS232C. For the connection to PC (with cable HD2110CSNM
or C206) or printer (with cable HD2110CSNM).

HD2109 - 6 - V2.4
Dissolved Oxygen – Temperature
HD2109.2

HD2109 - 7 - V2.4
HD2109.2
1. 8-pole DIN45326 connector, input for dissolved oxygen and temperature combined probes,
for Pt100 SICRAM temperature probes and direct 4-wire Pt100 probes complete with TP47
module.
2. External auxiliary power supply connector input (positive at centre).
3. Battery symbol: displays the battery charge level.
4. Function indicators.
5. Secondary display line.
6. CAL/key: during normal operation starts the dissolved oxygen probe calibration; in the
menu, increases the current value.
7. FUNC/ENTER key: during normal operation displays the maximum (MAX), the minimum
(MIN) and the average (AVG) of current measurements; in the menu, confirms the current
selection. This updates the display measurement when the Auto-Hold function is enabled.
8. REL/key: enables the relative measurement (displays the difference between the current
value and the logged value when the key is pressed); in the menu, decreases the current
value.
9. SERIAL/ERASE LOG key: starts and ends the data transfer to the serial communication
port. In the menu, clears the data contained in the instrument's memory.
10. LOG/DUMP LOG key: during normal operation, starts and ends the saving of the data in
the internal memory; in the menu, starts the data transfer from the instrument's memory to
the PC.
11. Mini-USB type B connector for USB 2.0. For the connection to PC (with cable CP23).
12. MENU key: allows access to and exit from the menu.
13. mg/l-%-ESC key: cyclically changes the main variable measurement between:
•dissolved oxygen concentration (in mg/l),
•saturation index (in %),
•barometric pressure (in mbar).
In the menu, cancels the operation in progress without making changes.
14. °C/°F key: when the probe is not connected, allows manual modification of the temperature.
When a probe with temperature sensor is connected, pressing this key twice changes the unit
of measurement from degrees Celsius to Fahrenheit.
15. ON-OFF/AUTO-OFF key: turns the instrument on and off; when pressed together with the
CAL key, disables the automatic turn off.
16. MAX, MIN and AVG symbols.
17. Main display line.
18. Line for symbols and comments.
19. 8-pole MiniDin connector for RS232C. For the connection to PC (with cable HD2110CSNM
or C206) or printer (with cable HD2110CSNM).

HD2109 - 8 - V2.4
KEYBOARD AND MENU DESCRIPTION
Foreword
The instrument keyboard is composed of single-function keys, like the MENU key, and double-
function keys such as the ON-OFF/Auto-OFF key.
In the double-keys, the function in the upper part is the "main function", while the one in the bottom
part is the "secondary function". When the instrument is in standard measurement mode, the main
function is active. In the menu or in conjunction with the FUNC key, the secondary function is en-
abled.
The pressing of a key is accompanied by a short confirmation beep: a longer beep sounds if the
wrong key is pressed.
Each key specific function is described in detail below.
ON-OFF/Auto-OFF key
The instrument is turned on and off using the ON/OFF key. The turning on enables all display seg-
ments for a few seconds. An auto-test follows which analyses the type of probe connected, and
reads its calibration information. In cases of a dissolved oxygen probe, the electrode calibration co-
efficient (SLOPE) is also displayed: this value must be between 0.500 and 1.500. A value close to
1.500 indicates an exhausted probe (see page 14 for how to proceed). Finally, the instrument is set
for normal measurement.
If a temperature probe is connected, the main line displays a dotted line (- - - -).
The connected probe's data are captured upon turning the instrument on: when the probe is
inserted into a functioning instrument, the "NEW_PROB_DET" message appears: turn the
instrument off and then back on again.
Replace the probes when the instrument is off.
+
Automatic turning off
The instrument has an AutoPowerOff function that automatically turns the instrument off after about
8 minutes if no key is pressed during the intervening time. The AutoPowerOff function can be dis-
abled by holding the CAL/key pressed down when turning the instrument on: the battery symbol
will blink to remind the user that the instrument can only be turned off by pressing the <ON/OFF>
key.

HD2109 - 9 - V2.4
The automatic turning off function is disabled when external power is used. On the other
hand, it cannot be disabled when the batteries are discharged.
FUNC/ENTER key
During normal measurement this enables the display and logging of the maximum (MAX), mini-
mum (MIN) and average (AVG) value of dissolved oxygen concentration, saturation index, baro-
metric pressure and temperature measurements, updating them with the acquisition of new samples.
The acquisition frequency is once a second. To switch from dissolved oxygen to barometric pres-
sure and to saturation index use the "mg/l-%-ESC" key.
In the menu, the ENTER key confirms the current parameter and then goes to the next one.
The MAX, MIN and AVG measurements remain in the memory until the instrument is on, even af-
ter exiting the calculation function. To reset the previous values and restart with a new measurement
session, press FUNC until the message "FUNC CLR" appears, then use the arrows to select YES
and confirm using ENTER.
The dissolved oxygen concentration (or barometric pressure or saturation index) and tem-
perature values are displayed at the same time. According to settings in the "RCD Mode"
menu item, the maximum, minimum and average indications have different meanings: please
see the description of this MENU key below.
Attention: the data captured using the Record function cannot be transferred to the PC.
CAL /key
It increases the current parameter when used in the menu; when used in measurement mode, it
starts the dissolved oxygen probe calibration (please see the chapter dedicated to calibration on
page 15).
°C/°F key
The temperature value measured by the sensor present in the dissolved oxygen probe is used to cal-
culate the saturation index and the dissolved oxygen concentration in the liquid being measured.
The key changes the unit of measurement between Centigrade or Fahrenheit.
mg/l -% / ESC key
It changes the main variable measurement between dissolved oxygen concentration (in mg/l),
barometric pressure (in mbar), and saturation index (in %).

HD2109 - 10 - V2.4
The instrument has an Auto-Hold function, which can be set in the MENU, that "freezes" the meas-
urement automatically when it has been stable (within 1 digit) for over 10 seconds: the message
HOLD is displayed.
To perform a new measurement, it is necessary to press the FUNC/ENTER key.
The HOLD message starts blinking, while the display follows the actual measurement trend, until it
stabilizes again and the HOLD message remains still.
In the menu, the key clears or cancels the active function (ESC).
REL/key
In measurement mode, it displays the difference between the current value and that measured on
pressing the key. The REL message appears on the display; press the key again to return to the
current measurement.
When used in the menu, it decreases the current variable value.
MENU Key
The first menu item is accessed by initially pressing on the MENU key; press ENTER to go to the
following items. To modify the item displayed, use the arrow keys (and ). The current value is
confirmed by pressing the ENTER key and the display moves on to the next parameter. If pressing
ESC the setting is cancelled.
To exit the menu, press the MENU key at any time.
The menu items are listed in this order:
1) Sample ID (Identifier of the sample being measured): it is an automatically increased
progressive number associated with the single PRINT function (print interval set to 0) for
the printing of labels. The index appears in the single sample printing together with date,
time, dissolved oxygen and temperature measured values. This menu item allows the value
of the first sample to be set: each time the PRINT key is pressed, the identification ID in the
printing is increased by 1 allowing progressive measurement of all measured samples. If the
Auto-Hold function, described below in this chapter, is enabled, the print time interval is
forced to zero. Pressing SERIAL only causes the print to occur when the measurement has
stabilized (HOLD symbol still). Later, it is possible to repeat the print at will, but while the
HOLD mode is on, the sample identifier number is not increased. This is useful when more
labels must be printed with the same identification code without increasing the code each
time.
The message "SMPL ID UNT=RSET SER=PRNT" is scrolled in the comment line: using
the arrows (and ) the currently measured sample identifier value can be changed.
By holding the °C/°F key down the proposed number is set to zero.
The instrument's heading information will be printed using the SERIAL key.
2) AUTO-HOLD function: the instrument normally operates in continuous view mode (de-
fault setting). In this mode the displayed measurement is updated every second. If the Auto-

HD2109 - 11 - V2.4
Hold function is enabled, the instrument performs the measurement and when it stabilizes it
goes in HOLD mode. To update the display indication, press FUNC/ENTER.
In the following figure you can see an example of the measurement process with the Auto-
Hold function enabled. A probe is immersed into a liquid at concentration C1and, to per-
form the measurement, the FUNC/ENTER key is pressed: The concentration measurement
raises progressively reaching the final value. The HOLD symbol blinks. In the stretch indi-
cated by 1, the measurement remains stable for 10 seconds, within two digits: at the end of
this interval (point 2), the instrument goes into HOLD mode, presenting the final stable
value.
2 digit
10s
t
Ο
2
C
1
3) SAL mg/l (Setting the salinity): the message "SAL mg/l – UNT=RSET" is scrolled in the
comment line. The display central line shows the current salinity value, and the secondary
line the corresponding dissolved oxygen concentration value. Use the arrows to enter this
value, and confirm using ENTER. To disable the salinity compensation, set the value to
zero: pressing the °C/°F key rapidly sets the value to zero without the need to use of the ar-
rows.
Note: the dissolved oxygen concentration depends on the measured liquid salinity. In con-
trast, salinity has no effect on the saturation index.
4) Management of memorized data (only HD2109.2): the message "LOG_DUMP_or_E-
RAS" (Transfer data or erase) is scrolled in the comment line. The center figure reports
the number of free memory pages (FREE). All memory data are permanently erased by
pressing SERIAL/EraseLOG. By pressing LOG/DumpLOG, the data transfer of the logged
data on the serial port is started: the "BAUD-RATE" must have previously been set to the
maximum value (please see the menu items described below and the paragraph "STORING
AND TRANSFERRING DATA TO A PERSONAL COMPUTER" on page 29).
5) Sleep_Mode_LOG (Automatic turning off during recording) (only HD2109.2): this
function controls the instrument's automatic turning off during logging, occurring between
the capture of a sample and the next one. When the interval is lower than 60 seconds, the in-
strument will always remain on. With intervals greater than or equal to 60 seconds, it is pos-
sible to turn off the instrument between loggings: it will turn on at the moment of sampling
and will turn off immediately afterwards, thus increasing the battery life. Using the arrows
select YES and confirm using ENTER in order to enable the automatic turning off, select
NO and confirm to disable it and keep the instrument on continuously.
Note: even if Sleep_Mode_LOG=YES is selected, the instrument does not turn off for less
than one minute intervals.
6) Print and log interval: sets the interval in seconds between two loggings or data transfers
to the serial port. The interval can be set at 0, 1s, 5s, 10s, 15s, 30s, 60s (1min), 120s (2min),
300s (5min), 600s (10min), 900s (15min), 1200s (20min), 1800s (30min) and 3600s (1hour).
If the value 0 is set, SERIAL works on command: the sending of data to the serial port
is performed each time the key is pressed. Recording (LOG) is performed with one sec-

HD2109 - 12 - V2.4
ond intervals even if the interval is set to 0. With an interval from 1 to 3600s, continuous
data transfer is started when the SERIAL key is pressed. To end the recording (LOG) and
continuous data transfer operations (SERIAL with an interval greater than 0), press the
same key again.
7) RCD MODE (Record mode): the instrument captures the dissolved oxygen concentration,
saturation index, barometric pressure and temperature values every second. The relationship
existing between these parameters is such that the maximum or minimum value of one gen-
erally does not correspond to the maximum or minimum value of the others. If the RCD
MODE parameter is set to "I Sat", the maximum (MAX) and minimum (MIN) values dis-
played using FUNC/ENTER refer to saturation: the remaining indicated parameters are
those measured at the maximum and minimum saturation index and not their maximum and
minimum values.
The same is true for the other items: "Conc" refers to dissolved oxygen concentration, "tp"
to temperature, "Press" to barometric pressure.
If the RCD MODE parameter is set to "tp", the maximum and minimum values displayed
using FUNC/ENTER refer to temperature: the other indicated parameters are those meas-
ured at the maximum and minimum temperature and are not the maximum and minimum of
the other variables.
If "Indep" (=independent) is selected, the maximum and minimum values displayed using
FUNC/ENTER are independent: the indicated values are the maximum and minimum of
each variable but are not necessarily referred to the same measurement moment.
8) YEAR: to set the current year. Use the arrows to modify this parameter and confirm using
ENTER.
9) MNTH (month): to set the current month. Use the arrows to modify this parameter and con-
firm using ENTER.
10) DAY: to set the current day. Use the arrows to modify this parameter and confirm using
ENTER.
11) HOUR: to set the current hour. Use the arrows to modify this parameter and confirm using
ENTER.
12) MIN: to set the current minutes. In order to correctly synchronize the minute, it is possible
to reset the seconds by pressing the °C/°F key. Use the arrows to set the current minute plus
one, and as soon as that minute is reached press °C/°F: this synchronizes the time to the
second. Press ENTER to go onto the next item.
13) BAUD_RATE: indicates the frequency used for the serial communication with the PC.
Values from 1200 to 38400 baud. Use the arrows to modify this parameter and confirm us-
ing ENTER. The communication between instrument and PC (or serial port printer)
only works if the instrument and PC baud rates are the same. If the USB connection is
used this parameter value is automatically set (please see the details on page 29).
LOG/DumpLOG key - only HD2109.2
In measurement mode, this function starts and stops the logging of a data block to be saved in the
instrument's internal memory. The data logging frequency is set in the "Print and log interval"
menu parameter. The data logged between a start and subsequent stop represent a block.

HD2109 - 13 - V2.4
When the logging function is on, the LOG indication is displayed, the battery symbol blinks and a
beep is issued each time a logging occurs; the battery symbol does not appear when using an
external power supply.
To end the logging, press LOG.
If the Auto-HOLD function is enabled (please see the menu), the data logging is disabled.
The HD2109.2 can turn off during logging between one capture and the next: the function is con-
trolled by the Sleep_Mode_LOG parameter. When the logging interval is less than one minute, the
logging instrument remains on; with an interval of at least one minute, it turns off between one cap-
ture and the next if the parameter Sleep_Mode_LOG=YES.
>>>
DUMP LOG - only HD2109.2
To start the transfer of the data contained in the instrument internal memory via the serial port, press
the MENU key. Using FUNC/ENTER select the "LOG_DUMP_or_ERAS" item, and then press on
the LOG/DumpLOG key.
Please see the paragraph dedicated to data transfer on page 29.
SERIAL key - only HD2109.1
SERIAL/EraseLOG key - only HD2109.2
In measurement mode, this function starts and stops the data transfer to the RS232C serial output.
According to the settings entered in the Print and log interval menu item, a single sample can be
printed if Print and log interval=0 or a continuous indefinite printing of the measured data can be
set up if Print and log interval=1…3600.
The printing operation is accompanied by the display of the RS232 symbol and the blinking of the
battery symbol; when using an external power supply the battery symbol does not appear.
Press SERIAL to end the continuous printing.
Before starting the printing with SERIAL, set the baud rate. To do so, select the Baud Rate menu
item and select the maximum value equal to 38400 baud by using the arrows. Confirm by pressing
ENTER.
The DeltaLog9 software for PC will automatically set the baud rate value during connection. If you
are using a different program than DeltaLog9, be sure the baud rate is the same for both the
instrument and the PC: the communication will only work in this way.
>>>
Erase memory - only HD2109.2
Press the MENU key to permanently clear all the data contained in the instrument's memory. Us-
ing FUNC/ENTER select the "LOG_DUMP_or_ERAS" item, and then press on the SERIAL key.

HD2109 - 14 - V2.4
MEASUREMENT OF THE DISSOLVED OXYGEN
The instruments work with combined probes of polarographic, with two or three electrodes, and
galvanic type with integrated temperature sensor, or with temperature probes with Pt100 sensor.
The dissolved oxygen probe is fitted with SICRAM module; the temperature probe can be a
SICRAM type or direct 4 wires.
The probe measures the dissolved oxygen partial pressure in the measured liquid, as well as the
temperature and the barometric pressure. Using these values, it calculates the dissolved oxygen
concentration in mg/l, and the saturation index (in %).
The temperature indication is displayed in the secondary line; the main line shows all the other
quantities.
The probe is detected during turn on, and this cannot be performed when the instrument is
already on, therefore if a probe is connected and the instrument is on, it is necessary to turn it
off and on.
How to measure
Some instructions on the instrument's operation procedures are reported below.
To measure the dissolved oxygen, immerse in the liquid the polarographic probe to a depth of at
least 80 mm or the galvanic probe to a depth of at least 50 mm.
It is essential that the liquid in front of the membrane is continually changed so as to avoid incorrect
measurements caused by oxygen exhaustion in the liquid in contact with the membrane. Check that
the liquid stirring is such that it avoids production of measurement variations.
While immersing the probe, check that no air bubbles remain trapped in contact with the membrane.
When connecting the probe to the instrument, wait a few minutes until the reading is stable and reli-
able. This time span serves to eliminate the dissolved oxygen in the probe's internal electrolyte.
The probe connected to the instrument is always aligned even if the instrument is off: in this condi-
tion the measurement can occur immediately after turning on, once the probe response stabilized.
Attention: when no measurement is taken for long periods, it is recommended that the probe be dis-
connected from the instrument to avoid useless consumption of the probe internal electrolyte. In the
galvanic probe, withdraw the probe internal electrolyte, to avoid useless consumption of the meas-
urement electrodes.
If the measurements are taken in a container, perform them with the container filled until running
over. Fit the container with a stirrer and adjust the stirring speed in order to obtain a stable reading
until equilibrium is reached, avoiding trapping air in the liquid.
While measuring running water, for example, water streams, check that the flow speed is sufficient,
otherwise remove the probe, pick up a sample and proceed as described above.

HD2109 - 15 - V2.4
Measurement of the concentration of dissolved oxygen
The probe must be calibrated periodically using the DO9709/20 (for polarographic probes
DO9709SS, DO9709SM and galvanic probe DO9709SG) or DO9709/21 (for galvanic probe
DO9709SS.1) calibrator.
The instrument checks the dissolved oxygen probe efficiency; the "CHNG MEMBRANE AND
ELECTROLYTE" message indicates that the probe is exhausted.
The same message is displayed during calibration: either when calibration is not possible or the
reading is unstable. It is thus necessary to replace the probe or clean the measurement cell with re-
placement of the electrolyte and/or the membrane covering the measurement electrodes.
Proceed as follows:
1. Connect the probe to the instrument.
2. Turn the instrument on with the ON/OFF key.
3. Wet the sponge contained in the calibrator using 2ml of distilled water.
4. Insert the probe into the calibrator.
5. Wait a few minutes until the system stabilizes thermally and 100% RH is reached inside the
calibrator.
6. Using "mg/l-%-ESC", select the measurement of dissolved oxygen concentration (SAT%).
7. Press CAL to start the calibration: press ENTER to confirm and exit the procedure, or ESC
to quit the calibration without making changes.
8. On pressing ENTER, the display shows the new gain value (SLOP) for a few seconds and then
will progressively reach 101.7%.
The instrument is calibrated and ready for use.
On pressing ENTER during calibration, the instrument checks that the correction to be made does
not exceed the expected limits for correct functioning. Slope between 0.500 and 1.500. If the cali-
bration is rejected because it is outside the admitted corrections, the CAL ERR message will ap-
pear, followed by the "CHNG MEMBRANE AND ELECTROLYTE" message. The instrument
maintains the previous calibration values until the probe's efficiency is restored.
Electrolyte solution and/or membrane replacement
The probe is supplied already filled with electrolyte solution and is ready for use. The electrolyte
contained in the dissolved oxygen probe will be exhausted because of the chemical reaction gener-
ated by the current in proportion to the partial pressure of the oxygen present in the water. Subse-
quently, the current generated by the probe is so low that the calibration operation is impossible. It
is necessary to replace the electrolyte contained in the probe to restore its functionality.
Incorrect use of the probe can cause the rupture or obstruction of the oxygen-permeable membrane con-
taining the electrolyte solution. In this case it is necessary to replace the membrane and the electrolyte
solution.
After replacement of the electrolyte solution and/or membrane, insert the probe's connector in the
instrument and wait 2 hours before performing the dissolved oxygen measurement (this is the nec-
essary time to exhaust the oxygen trapped in the electrolyte solution during the replacement).

HD2109 - 16 - V2.4
DO9709SM POLAROGRAPHIC PROBE
1. Remove the protective container from the head of the probe.
2. Unscrew the probe's head with the membrane permeable to oxygen.
3. If necessary, replace the membrane.
4. Fill the head of the probe with the supplied electrolyte solution.
5. Eliminate any possible air bubble in the electrolyte solution.
6. Screw the probe's head back on carefully.
DO9709SG GALVANIC PROBE
1. Remove the protective container from the head of the probe.
2. Unscrew the cap of the filling hole and the head of the probe with the membrane permeable to
oxygen (check that the membrane is in good condition).
3. Fill the head of the probe up to ¾ with KOH electrolyte solution.
4. Screw the head of the probe with the electrolyte solution to the probe. Rinse any excess
electrolyte solution with water.
5. Pour the electrolyte solution in the filling hole (the probe filling requires about 5 ml of
solution). From time to time, gently tap the probe stem to remove any air bubbles.
6. When the filling hole is full, screw the cap back on. Rinse any excess electrolyte solution with
water.
7. Place the probe with the membrane upwards and check that there are no air bubbles under the
membrane. If you notice air bubbles, further fill the probe with electrolyte solution.
Head of the probe
Membrane
Head of the probe
Filling hole

HD2109 - 17 - V2.4
8. Wait approximately 2 hours before using the probe, then calibrate.
ATTENTION:
The electrolyte solution contains Potassium Hydroxide (KOH) and is caustic!
Avoid contact with skin, use suitable gloves and protect the eyes. In case of
contact, rinse immediately and thouroughly with water.
Note: some residues (lead oxide and carbonate) due to the reaction of the electrolyte solution with
oxygen can be visible inside the membrane; such residues do not compromise the probe operability
and can be removed by unscrewing the head of the probe and rinsing the membrane during the
regular periodic maintenance. The accumulation of many residues in a short time (few days) may
indicate the presence of air bubbles inside the probe due to an incorrect filling, to the cap not suffi-
ciently closed or to leakage in the membrane.
DO9709SS POLAROGRAPHIC PROBE
1. Unscrew the probe's head with the membrane
permeable to oxygen.
2. If necessary, replace the membrane.
3. Fill the probe's head with the DO 9701
electrolyte solution until the level indicated in
the figure (filling level).
4. Eliminate any possible air bubble in the
electrolyte solution.
5. Screw the probe's head back on carefully.
DO9709SS.1 GALVANIC PROBE
1. Unscrew the probe's head and the membrane permeable to oxygen. If necessary, replace the
membrane.
2. Attach the needle to a 10 ml syringe.
3. Using the syringe, withdraw the DO 9701.1 electrolyte solution.
4. Remove the air bubbles inside the syringe. Insert the needle into one of the four
holes surrounding the cathode of the probe and inject the solution until it leaks
out. The fill volume is approximately 5 ml.

HD2109 - 18 - V2.4
5. Screw the probe's head back on carefully.
Check the probe's status
The glass body covering the cathode of the polarographic probe and the membrane on the probe's
head should not be damaged.
If there are cracks in the glass body, the probe must be replaced. If the oxygen-permeable mem-
brane is damaged, dirty or obstructed it must be replaced. When the probe's head is unscrewed the
probe is not protected. Handle it with care to avoid collisions that could damage it irreparably.
Control the zero of the probe
Compensation of the zero (offset) of the probe is already done in the factory.
The user can control the offset by immersing the probe in the 0.0% dissolved oxygen solution (DO
9700):
•pour a small quantity of 0.0% dissolved oxygen solution into a container, after suitably
cleaning the container with distilled water,
•insert the probe in the zero solution and wait at least 5 minutes,
•the instrument should indicate a saturation index < 0.6%.
Dissolved oxygen probe storage
When the dissolved oxygen probe is not used it should be disconnected from the instrument to
avoid useless consumption of the electrolyte solution and the discharge of the batteries.
When no measurement is taken for long periods, withdraw the internal electrolyte of the galvanic
probe, to avoid useless consumption of the measurement electrodes.
Always keep the electrode wet using the special cap provided with the probe and filled with dis-
tilled water.

HD2109 - 19 - V2.4
Polarographic probe and galvanic probe: differences
To help choosing between the use of a polarographic or galvanic probe, the following table summa-
rizes the main differences between the two probes.
Polarographic probe
DO9709SM
Galvanic probe
DO9709SG
Polarization time After connecting the probe to the in-
strument it is necessary to wait at
least 5 minutes before taking the
measurement.
Polarization is not needed. After con-
necting the probe to the instrument it
is possible to take the measurement
immediately.
Flow rate Requires a lower flow rate (> 9 cm/s),
because it consumes less oxygen.
Requires a higher flow rate (> 20 cm/s),
because it consumes more oxygen.
Electrodes life Longer, because the electrodes are
not consumed when the probe is dis-
connected from the instrument.
Shorter, because the electrodes are
consumed even when the probe is
disconnected from the instrument (if
the electrolyte is not removed).
Maintenance Requires little maintenance. The electrolyte solution must be re-
placed more frequently.
Accuracy Higher accuracy (± 1% f.s.). Standard accuracy (± 2% f.s.).
Firmware update for DO9709SM and DO9709SG probes
The DO9709SM and DO9709SG probes are compatible with HD2109 instruments starting from
firmware version 2.08. The instruments with previous firmware versions must be updated through
the DeltaLog 9 software. For the firmware updating procedure, see the instructions of the software.
Only for DO9709SM probes, after updating the firmware, you must perform the following ohmic ca-
libration:
1. With the instrument switched off, remove the connected SICRAM probe, if any.
2. Switch on the instrument.
3. When "SELF TEST" appears on display, press the REL button.
4. After the “self test”, the instrument displays the scrolling message "SET_ 0 DEG".
5. Connect the calibrator with value 1000 ohm to the instrument.
6. Wait a few moments for the detected value to be stable and press ENTER.
7. The instrument displays the scrolling message "SET_ 400 DEG".
8. Remove the calibrator with value 1000 ohm and connect the calibrator with value 2479 ohm
to the instrument.
9. Wait a few moments for the detected value to be stable and press ENTER.
10. The instrument displays the scrolling message "SET_ 0 DEG" again. Verify that calibration is
correct: the instrument must measure 0 °C when the calibrator with value 1000 ohm is con-
nected and 400 °C when the calibrator with value 2479 ohm is connected. If necessary, repeat
the calibration from step 5.
11. The calibration is complete, switch off the instrument.

HD2109 - 20 - V2.4
Pt100 TEMPERATURE PROBE
The instrument accepts the input of Platinum temperature probes with resistances of 100Ωwith
SICRAM module or direct 4 wires.
The excitation current was chosen in order to minimize the sensor self-heating effects.
The probes with direct 4-wire input are checked for conformity with class A tolerance accord-
ing to norm IEC751 - BS1904 - DIN43760.
The °C or °F unit of measurement can be chosen for display, printing, and logging using the °C/°F
key.
How to measure
The temperature measurement by immersion is carried out by inserting the probe in the liquid for at
least 60 mm; the sensor is housed in the end part of the probe.
In the temperature measurement by penetration the probe tip must be inserted to a depth of at least
60 mm, the sensor is housed in the end part of the probe. When measuring the temperature on fro-
zen blocks it is convenient to use a mechanical tool to bore a cavity in which to insert the tip probe.
In order to perform a correct contact measurement, the measurement surface must be even and
smooth, and the probe must be perpendicular to the measurement plane.
So as to obtain the correct measurement, the insertion of a drop of oil or heat-conductive
paste is useful (do not use water or solvents). This method also improves the response time.
Instructions to connect the TP47 module for 4-wire Pt100 probes
All Delta Ohm probes are provided with a connector. The HD2109.1 and HD2109.2 instruments
also work with direct 4-wire Pt100 probes manufactured by other producers: for the instrument
connection is prescribed the TP47 connector to which the probe's wires should be welded.
The instructions to connect the Platinum probe to the TP47 module are provided below.
The module is supplied complete with fairlead and gasket for 5mm maximum diameter cables.
Do the following to open the module and connect a probe.
Unscrew the fairlead and extract the gasket, remove the label using a cutter, unscrew the ring on the
opposite side as illustrated in the figure: