Hanna Instruments HI 2550 User manual

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Multiparameter
pH/ORP/°C
EC/TDS/NaCl
Bench Meter
HI2550
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 this instrument.
This manual will provide you with the necessary information for correct
use of this instrument, as well as a precise idea of its 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
FUNCTIONAL DESCRIPTION.............................................................5
SPECIFICATIONS............................................................................6
OPERATIONAL GUIDE.....................................................................8
AUTO‑RANGING...........................................................................12
pH CALIBRATION .........................................................................13
pH BUFFER TEMPERATURE DEPENDENCE ......................................18
RELATIVE mV CALIBRATION..........................................................19
EC/TDS CALIBRATION...................................................................19
CONDUCTIVITY VERSUS TEMPERATURE CHART...............................21
NaCl CALIBRATION.......................................................................22
GOOD LABORATORY PRACTICE (GLP)..............................................23
LOGGING FUNCTION.....................................................................28
SETUP........................................................................................35
TEMPERATURE CALIBRATION (FOR TECHNICAL PERSONNEL ONLY)42
mV CALIBRATION (FOR TECHNICAL PERSONNEL ONLY) ...................44
PC INTERFACE .............................................................................45
ELECTRODE CONDITIONING AND MAINTENANCE.............................51
TROUBLESHOOTING GUIDE ..........................................................54
TEMPERATURE CORRELATION FOR pH SENSITIVE GLASS.................55
ACCESSORIES..............................................................................56
TABLE OF CONTENTS

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GENERAL DESCRIPTION
The HI2550 is a microprocessor based pH, ORP, Conductivity (EC), TDS,
NaCl, and Temperature Bench Meter. Relative mV feature is also provided.
pH measurements are compensated for temperature effect manually or
automatically with the HI7662 temperature probe.
Up to a five‑point pH calibration can be performed using seven standard
buffers and two custom buffers.
A calibration due alarm can be set to alert the user that too much time
has elapsed since the last pH calibration.
Conductivity and TDS features auto‑ranging, which automatically selects
the scale with the highest resolution. Conductivity measurements are
compensated for temperature manually or automatically with a tem‑
perature sensor located inside the probe. The temperature coefficient is
user selectable. Temperature compensation can be disabled to measure
actual conductivity.
The GLP feature provides data consistency.
Data can be stored in the meters memory for later retrieval. The meters
memory can hold 200 manually logged points and 500 lot logging points.
An USB connection ensures communication with a PC.
Remove the instrument from the packing material and examine it carefully
to make sure that no damage has occurred during shipping. If there is any
damage, please contact your local Hanna Instruments Office.
Each instrument is supplied with:
• HI1131B Glass‑body Combination pH Electrode with 1 m (3.3’)
Cable
• HI76310 Conductivity / TDS probe
• HI7662 Temperature Probe
• HI76404N Electrode Holder
• pH4.01 & 7.01 Buffer Solutions (20 mL each)
• HI7082 Electrolyte Solution
• 12VDC Power Adapter
• Instruction Manual
• Quick Reference Guide
• Quality Certificate
Note: Save all packing material until you are sure that the instrument
functions correctly. All defective items must be returned in the
original packing with the supplied accessories.
PRELIMINARY EXAMINATION

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1) Liquid Crystal Display (LCD).
2) CAL key, to enter and exit calibration mode.
RCL key (alternate function), to enter and exit memory recall.
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 parameters.
TC key (alternate function), to view temperature coefficient value.
5) ºC key, to manually decrease temperature value or other parameters.
ATC key (alternate function), to select EC temperature compensation mode.
6) SETUP key, to enter/exit SETUP mode.
LOCK key (alternate function), to freeze current EC range on the LCD.
7) RANGE key, to select measurement range (pH, mV, EC), switch to focused
data in SETUP or toggle between buffer value and temperature during
calibration.
MODE key (alternate function) to select mV or Rel mV on mV range or EC,
TDS, NaCl on EC range.
8) LOG/CLR key, to store a value into memory, to clear pH calibration, or to
select to delete log records or lots.
9) ALT key, to select alternate function.
10) ON/OFF switch.
11) Power supply socket.
12) USB connector.
13) EC electrode connector.
14) BNC electrode connector.
15) Temperature probe socket.
16) Electrode reference socket.
FUNCTIONAL DESCRIPTION
Front Panel
Rear Panel

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SPECIFICATIONS
(*)Uncompensated conductivity (or TDS) is the conductivity (or TDS) value without
temperature compensation.
RANGE
–2.0 to 16.0 pH
–2.00 to 16.00 pH
–2.000 to 16.000 pH
±999.9 mV (ISE & ORP)
±2000 mV (ISE & ORP)
0.00 to 29.99 µS/cm
30.0 to 299.9 µS/cm
300 to 2999 µS/cm
3.00 to 29.99 mS/cm
30.0 to 200.0 mS/cm
up to 500.0 mS/cm uncompensated(*) conductivity
0.00 to 14.99 ppm
15.0 to 149.9 ppm
150 to 1499 ppm
1.50 to 14.99 g/l
15.0 to 100.0 g/l
up to 400.0 g/l uncompensated(*) TDS
(with 0.80 factor)
0.0 to 400.0% NaCl
–20.0 to 120.0 ºC (pH, EC range)
RESOLUTION
0.1 pH
0.01 pH
0.001 pH
0.1 mV (±1000 mV)
1 mV (±2000 mV)
0.01 µS/cm
0.1 µS/cm
1 µS/cm
0.01 mS/cm
0.1 mS/cm
0.01 ppm
0.1 ppm
1 ppm
0.01 g/l
0.1 g/l
0.1% NaCl
0.1 ºC

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ACCURACY
@ 20 °C / 68 °F
±0.01 pH
±0.002 pH
±0.2 mV (±999.9 mV)
±1 mV (±2000 mV)
±1 % reading (±0.05 µS/cm or 1 digit,
whichever is greater)
±1 % of reading (±0.03 ppm or 1 digit,
whichever is greater)
±1% of reading
±0.4 ºC (excluding probe error)
Rel mV offset range ±2000 mV
pH Calibration 1, 2, 3, 4 or 5 point calibration,
7 standard buffers available
EC Calibration
1 point slope calibration;
6 buffers available:
84.0, 1413 µS/cm
5.00, 12.88, 80.0, 111.8 mS/cm
1 point offset: 0.00 µS/cm
NaCl Calibration 1 point with HI7037L buffer (optional)
Temperature
compensation
Manual or Automatic from:
–20.0 to 120.0 ºC (pH RANGE)
–20.0 to 120.0 ºC (EC RANGE)
(can be disabled on conductivity range to measure
actual conductivity
Conductivity
temperature
coefficient
0.00 to 6.00 %/ºC
(for EC and TDS only)
default value is 1.90 %/ºC
TDS factor 0.40 to 0.80 (default value is 0.50)
pH Electrode HI1131B
EC Probe HI76310
Temperature probe HI7662
Input impedance
(BNC input) 1012 ohms
Log on demand feature 200 records
Log Interval feature
500 records Stability logging (”StAb”),
5, 10, 30 sec
1, 2, 5, 10, 15, 30, 60, 120, 180 min
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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OPERATIONAL GUIDE
POWER CONNECTION
Plug the 12 VDC adapter into the power supply socket.
Notes: This instrument uses non volatile memory to retain the
calibration parameters and all other settings, even when unplugged.
Make sure a fuse protects the main line.
ELECTRODE AND PROBE CONNECTIONS
For pH or ORP measurements connect an electrode with internal reference
to the BNC connector on the back of the instrument.
For electrodes with a separate reference connect the electrode’s BNC to the
BNC connector and the reference electrode plug to the reference socket.
For temperature measurements and automatic temperature compensation
connect the temperature probe to the appropriate socket.
For EC/TDS measurements connect the probe to the 7‑pin connector.
Make sure the probe sleeve is properly inserted.
INSTRUMENT START-UP
• Turn the instrument on by pressing the ON/OFF switch located on
the rear panel.
• All LCD tags are displayed and a beep is sounded while the instruments
perform a self test.
• The instrument will display “LoAd” message and “ ” blinking until
initialization is complete.
Notes: The instrument starts in the same range and mode as it
was at power off.
The ALT&MODE keys change the measuring modes:
- mV or Rel mV
- EC or TDS or NaCl
The RANGE key toggles between measurement ranges:
- pH, mV or Rel mV, EC or TDS or NaCl.
pH MEASUREMENTS
Make sure the instrument has been calibrated before
taking pH measurements.
• Submerse the electrode tip and the temperature
probe approximately 3 cm (1¼”) into the
sample to be tested and stir gently. Allow time
for the electrode to stabilize.

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• The pH is displayed on the primary LCD and the temperature on the
secondary LCD.
• If the reading is out of range, the closest full‑scale value will be
displayed blinking on the primary LCD.
If measurements are taken successively in different samples, it is
recommended to rinse the electrode thoroughly with deionized water
or tap water and then with some of the next sample to prevent
cross‑contamination.
The pH reading is affected by temperature. In order to measure the pH
accurately, the temperature effect must be compensated for. To use the
Automatic Temperature Compensation feature, connect and submerse
the HI7662 temperature probe into the sample as close as possible to
the electrode and wait for a few seconds.
If the temperature of the sample is known, manual temperature compen‑
sation can be used by disconnecting the temperature probe.
The display will show the last temperature reading the
“MTC” tag and the “ºC” tag blinking.
The temperature can now be adjusted with the ARROW
keys (from –20.0 ºC to 120.0 ºC).
mV/ORP MEASUREMENTS
An optional ORP electrode must be used to perform ORP measurements
(see Accessories).
Oxidation‑Reduction Potential (REDOX) measurements provide the
quantification of the oxidizing or reducing power of the tested sample.
The surface of the ORP electrode must be clean and smooth in order to
obtain an accurate measurement.
• Press RANGE to enter mV range.
• Submerse the tip of the ORP electrode 3 cm (1¼”)
into the sample to be tested and allow a few
seconds for the reading to stabilize.
• The instrument displays the mV reading on the
primary LCD and the temperature on the secondary
LCD line.

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• If the reading is out of range, the closest full‑scale value will be
displayed blinking on the primary LCD.
RELATIVE mV MEASUREMENTS
• Press the ALT&MODE keys simultaneously while in mV range. The
“mV” and “Rel” tags are displayed.
The reading displayed by the instrument is equal to the difference between
the current mV input value and the relative mV offset established in the
relative mV calibration.
CONDUCTIVITY MEASUREMENTS
Connect the conductivity probe to the instrument.
• Press the RANGE key to enter conductivity measurement range (EC).
• Submerse the probe into the solution to be tested. The
sleeve holes must be completely submersed. Tap the
probe repeatedly to remove any air bubbles that may
be trapped inside the sleeve.
• The conductivity value will be displayed on the primary LCD and the
temperature on the secondary LCD.
• If the reading is out of range, the full‑scale value (200.0 for MTC/ATC
mode or 500.0 for actual conductivity) will be displayed blinking.
• If LOCK key was pressed and the reading goes out of range, the
full‑scale value of the frozen range will be displayed blinking.
The conductivity reading is affected by temperature.
Three options for temperature compensation are available in conductivity
measurement mode.