Hanna Instruments HI 2400 User manual

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Dissolved Oxygen
Bench Meter
HI2400
Instruction Manual
www.hannainst.com

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Dear Customer,
Thank you for choosing a Hanna Instruments product.
Please read this instruction manual carefully before using these
instruments.
This manual will provide you with the necessary information for correct
use of these instruments, as well as a precise idea of their versatility.
If you need additional technical information, do not hesitate to e‑mail
us at [email protected] or view our worldwide contact list at
www.hannainst.com.
All rights are reserved. Reproduction in whole or in part is prohibited
without the written consent of the copyright owner.

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PRELIMINARY EXAMINATION ..........................................................4
GENERAL DESCRIPTION..................................................................4
PROBE FUNCTIONAL DESCRIPTION..................................................5
FUNCTIONAL DESCRIPTION.............................................................6
SPECIFICATIONS............................................................................7
OPERATIONAL GUIDE.....................................................................8
DO CALIBRATION.........................................................................11
GOOD LABORATORY PRACTICE (GLP)..............................................13
SETUP........................................................................................14
LOGGING.....................................................................................19
TEMPERATURE CALIBRATION (for technical personnel only) .............22
PC INTERFACE .............................................................................24
PROBE AND MEMBRANE MAINTENANCE........................................28
TROUBLESHOOTING GUIDE ..........................................................29
ACCESSORIES..............................................................................30
TABLE OF CONTENTS

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GENERAL DESCRIPTION
PRELIMINARY EXAMINATION
HI2400 is a logging microprocessor‑based DO/Temperature bench meter.
It can store up to 100 lots in memory, with up to 8000 readings.
These readings can be transferred to a computer for further analysis or
permanent storage.
Dissolved Oxygen is indicated in ppm (parts per million) or in %.
All measurements are automatically compensated for temperature.
Salinity compensation in water allows direct determination of Dissolved
Oxygen in saline waters and altitude compensation readjusts for the
altitude variance.
The Dissolved Oxygen probe has a membrane covering the polarographic
sensors and a built‑in thermistor for temperature measurements and
compensation.
This permeable PTFE membrane isolates the sensor elements from the
testing solution, but allows Oxygen to pass through. When a voltage is
applied across the sensor, oxygen that has passed through the membrane
reacts causing a current flow, and hence determining a reading.
Remove the instrument from the packing material and examine it carefully
to make sure that no damage has occured during shipping. If there is any
damage, please contact your local Hanna Instruments Office.
Each instrument is supplied with:
• HI76407/2 DO probe with 2 m (6.7’) cable
• HI76407A membrane cap (2 pcs)
• HI7041S electrolyte solution (30 ml)
• 12 VDC power adapter
• Instruction Manual
Note: Save all packing material until you are sure that the instrument
functions correctly. All defective items must be returned in their
original packing with the supplied accessories.

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1. DO Probe
2. Protective Cap
3. Watertight Shielded Cable
4. Polypropylene Probe Body
5. Temperature Sensor
6. O‑Ring Seal
7. Silver Chloride Anode
8. Platinum Cathode (sensor)
9. Oxygen Permeable PTFE Membrane
10. Membrane Cap
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PROBE FUNCTIONAL DESCRIPTION

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1) Liquid Crystal Display (LCD).
2) CAL key, to enter and exit calibration mode.
3) CFM/GLP key, to confirm calibration selection, different setup values
or to display Good Laboratory Practice information.
4) ºC key, to manually increase temperature value or other param‑
eters.
5) ºC key, to manually decrease temperature value or other param‑
eters.
6) SETUP key, to enter/exit SETUP mode.
7) RANGE key, to select measurement range (% or ppm), switch
to focused data in SETUP or toggle between standard value and
temperature during calibration.
8) LOG/CLR key, to store a value into memory, or to select to delete
log records.
9) RCL key, to enter and exit view memory mode.
10)ON/OFF switch.
11)Power supply socket.
12)USB connector.
13)DO probe connector.
FUNCTIONAL DESCRIPTION
Front Panel
Rear Panel

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SPECIFICATIONS
RANGE
0.00 to 45.00 ppm
0.0 to 300.0%
0.0 to 50.0 ºC (32.0 to 122°F)
RESOLUTION
0.01 ppm
0.1%
0.1 °C
ACCURACY
(@20 °C / 68 °F)
±1.5% of full scale or ±1 digit,
whichever is greater
±0.2 ºC (excluding probe error)
Typical EMC Deviation ±1.5% of full scale
±0.5 ºC
DO Calibration Single or double point at 0%
(HI7040) and 100% (in air)
Altitude
Compensation
Resolution
0 to 4,000 m (13,120’)
100 m (328’)
Salinity
Compensation
Resolution
0 to 40 g/l
1 g/l
Temperature
Compensation
0.0 to 50.0 ºC
(32.0 to 122 ºF)
Probe HI76407/2 with 2 m (6.6’) cable
Logging interval
5, 10, 30 seconds
or 1, 2, 5, 10, 15, 30, 60, 120,
180 minutes
PC communication Optoisolated USB
Power supply 12 VDC adapter
Dimensions 235 x 222 x 109 mm (9.2 x 8.7 x 4.3”)
Weight 1.3 Kg (2.9 lb)
kit with holder 2.1 Kg (4.6 lb)
Environment 0 – 50 ºC (32 ‑ 122 ºF)
max. 95% RH non condensing
Warranty 2 years

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Shipping
cap
black
red
FILL FIRST
THEN TAP
THEN SCREW
BACK ON
OPERATIONAL GUIDE
POWER CONNECTION
Plug the 12 VDC adapter into the power supply socket.
Notes: • This instrument use non volatile memory to retain the cali-
bration parameters and all the other settings even when unplugged.
• Make sure a fuse protects the main line.
PROBE CONNECTION AND PREPARATION
To take measurements, connect the DO
probe to the meter securely by aligning
the pins with the socket located on the
back of the meter, pushing the plug in and
tightening the threaded ring.
Probes shipped from Hanna Instruments
are dry. To hydrate the probe and prepare
it for use, connect it to the meter and
proceed as follows:
1. Remove the red and black plastic cap.
This cap is for shipping purposes and
can be thrown away.
2. Wet the sensor by soaking the bottom
2½ cm (1”) of the probe in electrolyte
(HI7041S) for 5 minutes.
3. Rinse the membrane cap (HI76407A
supplied in the kit with the meter)
with electrolyte solution while shaking
it gently. Refill with clean electrolyte
solution.
4. Tap gently the sides of the membrane
cap with your finger tip to ensure that
no air bubbles are trapped. To avoid
damaging the membrane, do not tap
it directly on the bottom.
5. Make sure that the rubber O‑ring sits
properly inside the membrane cap.
6. With the sensor facing down, slowly screw the cap clockwise. Some
electrolyte will overflow.
When not in use and during polarization (see page 9), use the protective
transparent cap supplied in the kit with the meter.

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INSTRUMENT START-UP
• Turn the instrument on by pressing the ON/OFF switch.
• All LCD tags are displayed and a beep is generated while the instru‑
ment performs a self test.
• The instrument will display “ ” blinking until initialization is
complete.
• After a few seconds “Cond” message appears on the LCD to inform the
user that the probe is in auto‑conditioning (automatic polarization)
mode.
• When this message disappears, the probe is polarized and the
instrument can be calibrated.
• If the probe is disconnected, the meter will display “----”.
PROBE POLARIZATION
The probe is under polarization with a fixed voltage of approximately
800 mV. Probe polarization is essential for stable measurements with
the same recurring degree of accuracy.
With the probe properly polarized, oxygen is continually consumed when
it passes through the sensitive diaphragm and dissolves in the electrolyte
solution contained in the probe. If polarization is interrupted, the elec‑
trolyte solution continues to be enriched with oxygen until it reaches an
equilibrium with the surrounding solution.
Whenever measurements are taken with a non‑polarized probe, the
oxygen level revealed is both that of the tested solution, as well as that
present in the electrolyte solution. This reading is incorrect.
The calibration of this instrument is very simple. Before proceeding with
the calibration, make sure the probe is ready for measurements (see
page 8), i.e. the membrane cap is filled with electrolyte and the probe
is connected to the meter and properly polarized.
For an accurate calibration, it is recommended to wait at least 15 minutes
to ensure precise conditioning of the probe. Keep the protective cap on
during polarization time and remove it for calibration and measurements.
Follow the calibration procedure (see page 11).

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SALINITY AND ALTITUDE COMPENSATION
If the sample contains significant concentration of salinity or if you are
performing measurements at an altitude different from sea level, the
read out values must be corrected, taking into account the lower degree
of oxygen solubility in these situations (see pages 15‑16).
Remember to set the altitude and/or the salinity before taking any DO
measurements. The meter will automatically compensate for these factors.
DO MEASUREMENTS
Make sure that the instrument has been calibrated and the
protective cap has been removed.
• Submerse the tip of the probe in the sample to be
tested. Allow approximately one minute for the reading
to stabilize.
• The Dissolved Oxygen value (in %) is displayed on the primary LCD
and the temperature on the secondary LCD.
• Press RANGE to change the reading from % to ppm and vice‑versa.
For accurate Dissolved Oxygen measurements, a water movement of
0.3 m/s is required. This is to ensure that the oxygen‑depleted membrane
surface is constantly replenished. A moving stream will provide adequate
circulation.
The use of a magnetic stirrer to ensure a certain fluid velocity is rec‑
ommended.
TEMPERATURE MEASUREMENTS
The probe has a built‑in temperature sensor.
The measured temperature is indicated on the secondary LCD as shown
above.
Allow the probe to reach thermal equilibrium before taking any measure‑
ment. This can take several minutes. The greater the difference between
the temperature at which the probe was stored and the temperature of
the sample, the longer the time will be.
Note: If “----” is displayed, the DO probe is not properly connected.
This also indicates the possibility of a broken probe cable. If the
temperature is displayed blinking, the temperature is out of range.