Oakton PH550 User manual

PH550 Benchtop pH Meter
Instruction Manual
Oakton Instruments
www.4oakton.com
Manual Version 3.2

Table of Contents
1Brief Introduction ............................................................................................................- 1 -
1.1 Main Features...................................................................................................................... - 1 -
2Technical Specifications....................................................................................................- 1 -
3What’s in the Box?...........................................................................................................- 2 -
4Instrument Description ....................................................................................................- 2 -
4.1 LCD Display .......................................................................................................................... - 2 -
4.2 Keypad ................................................................................................................................ - 3 -
4.3 Connectors .......................................................................................................................... - 4 -
4.4 Stable reading display mode................................................................................................. - 4 -
4.5 Data storage, recall, and deletion ......................................................................................... - 4 -
4.6 Max/Min Function ............................................................................................................... - 5 -
5pH Measurement.............................................................................................................- 5 -
5.1 Preparation.......................................................................................................................... - 5 -
5.2 pH Electrode Information ..................................................................................................... - 5 -
5.3 Information regarding Calibration......................................................................................... - 6 -
5.4 pH Meter Calibration............................................................................................................ - 8 -
5.5 Measuring pH ...................................................................................................................... - 9 -
5.6 Parameter Setting .............................................................................................................. - 11 -
5.7pH Electrode’s Maintenance ............................................................................................... - 12 -
6mV measurement ..........................................................................................................- 13 -
6.1 ORP measurement ............................................................................................................. - 13 -
6.2 Notes on ORP measurement............................................................................................... - 13 -
7Recommended pH Electrodes for Specific Applications................................................... - 14 -
8Warranty .......................................................................................................................- 14 -

- 1 -
1 Brief Introduction
Thank you for purchasing Oakton Instruments PH550 Benchtop pH meter.
This instrument is an outstanding combination of advanced electronics design and sensor technology. It’s the
most economical choice of a reliable lab-grade benchtop pH meter. Please read this maual carefully to
properly use and maintain the meter. Oakton Instruments reserves the right to update the contents of this
manual without giving prior notices.
1.1 Main Features
•The meter has a built-in microprocessor chip, which enables intelligent functions such as automatic
calibration, automatic temperature compensation, data storage, parameter setup, max/min reading
display, etc.
•The advanced automatic calibration mode has calibration guide and self-diganosis functions,
automatically recognizing standard buffer solutions (USA or NIST series).
•The advanced digital processing technology intelligently improves the meter’s response time and
measuring accuracy with stable reading display mode available.
•The kit comes with a 3-in-1 combination pH Electrode, measuring pH and temperature simultaneously.
•IP54 dustproof and spillproof. Connectors are protected by silicone seal caps, effectively ensuring the
reliability and service life of the meter under harsh environment.
•Detachable electrode holder and 3 bottles of pH buffer solutions come with the kit for convenient use.
2 Technical Specifications
pH
Range
0 to 14.00 pH
Resolution
0.01/0.1 pH
Accuracy
±0.01 pH ±1 digit
Temperature
Compensation
0 to 100 ˚C (Auto or Manual)
Calibration
1 to 3 points automatic calibration
mV
Range
-1999 mV - 0 - 1999 mV
Resolution
1 mV
Accuracy
±0.1% F.S ±1 digit
Temp.
Range
0 to 100˚C; 32 to 212°F
Resolution
0.1˚C; 0.1/1°F
Accuracy
±0.5˚C ±1 digit
Others
Data Storage
50 groups
Storage Content
Numberings, Measurement, Unit, Temperature, Temperature
Compensation Status
Power
DC9V/300mA
IP Ratings
IP54 dustproof and spillproof
Size and Dimension
(240*235*103) mm/1kg

- 2 -
3 What’s in the Box?
Content
Quantity
3.1
35419-30, PH550 Benchtop pH Meter
1
3.2
35419- 31, Plastic 3-in-1 Combination pH Electrode
1
3.3
pH standard buffer solutions (4.00/7.00/10.01 pH;
(50ml for each)
1 for each
3.4
9V Power Adapter
1
3.5
Electrode Holder
1 set
3.6
Instruction Manual
1
4 Instrument Description
4.1 LCD Display
(1) — Measurement value
(2) — Calibration icons and numberings
(3) — Measurement unit
(4) — Temperature and reminder icons
(5) — The pH unit displayed during calibration
(6) — The pH value displayed during calibration, numberings for storage and recall, and reminder icons
(7) — Icons for data storage and recall — M+: store measuring data; RM: Recall measuring data
(8) — Self-Diagnosis icons and numberings
(9) — Temperature compensation mode icons — ATC: Auto Temperature Compensation; MTC: Manual
Temperature Compensation
(10) — Completed calibration icons
(11) — Stable reading icon
(12) — Icons for maximum and minimum values
Figure-1

- 3 -
4.2 Keypad
3.2.1. Keypad operations
Short press ----- <1.5 seconds; Long press ----- >1.5 seconds.
3.2.2 For keypad operation, please see Table-1.
Table – 1 Keypad operations and descriptions
Keypad
Operation
Functions
Short Press
•Power on/off
Short Press
•Select measuring mode: pH→mV.
Long Press
•Enter parameter setting：P1→P2→…P4.
Short Press
•Enter Calibration mode
•Cancel any operation and go back to measurement mode
Short Press
•In calibration mode, press to conduct calibration
•In parameter setting, press to confirm selection
Short Press
•Store measuring data
Long Press
•Recall stored measuring data
Short Press
or
Long Press
•In manual temperature compensation mode, short press to change
temperature, long press to change quickly
•In parameter setting mode, short press to change parameter and settings.
•In recall mode, short press to change numberings, long press to change
quickly.
Short Press
•Buttons for max/min values (refere to section 3.6)
Figure-2

- 4 -
4.3 Connectors
Symbol
Connector Name
Connector Type
REF
Socket for reference electrode
Φ2 banana type
pH/mV
Socket for pH and ORP electrode
BNC
TEMP
Socket for temperature sensor
RCA
DC9V
DC9V power socket
Φ2.5 direct type
4.4 Stable reading display mode
When the measuring value is stable, smiley face icon appears on LCD, see
Figure-3. Please do not get the reading value or make calibration until the
icon appears and stays.
4.5 Data storage, recall, and deletion
Storage
When the measurement is stable, press key, the meter displays
M+ icon and storage numberings on LCD, and stores the measuring data.
In Figure-4, the meter stores the first group of the measuring data. Press
again, to keep storing.
Recall stored data
In the measurement mode, long press key to recall the last stored
Measuring data. The meter displays RM icon and storage numberings.
In Figure-5, the meter is recalling the 28th stored measuring data.
Keep pressing and to recall the stored
measuring data successively. Press and hold and to quickly recall the stored
measuring data. Short press to go back to measurement mode.
Figure - 3
Figure - 5
Figure - 4

- 5 -
Clear stored data
The meter can store 50 groups of data. Once the storage is full, if user
presses again, the FUL icon will be displayed on LCD (see Figure-6).
The storage needs to be cleared in parameter setting P4 so as to keep storing
data. The numberings in M+ indicates the total number of stored data; The
numberings in RM indicates the number of stored data in current mode (ph/mV).
For example, if 20 groups of data are stored in pH mode, and 10 groups in mV
mode, then the numberings for M+ will be “M+30” in both pH and mV mode;
the numberings for RM in pH mode would be “RM20”, in mV mode “RM10”.
4.6 Max/Min Function
Use this function to display the maximum or minimum records out of groups of measuring data. In
measurement mode, press , LCD will display flashing icons of “MAX/MIN”, indicating the meter has
entered the mode of recording maximum and minimum data. After testing, press again, LCD will
alternately display the maximum and minimum value in the past measurements. Press to go back to
regular measurement mode.
5 pH Measurement
5.1 Preparation
Install the electrode holder
The electrode holder is composed of a metal stand base, a supporting pole, and an electrode clip. First, install
the metal stand base to the meter (screw it on). Please note that the metal base can be installed on either side
of the meter. Then install the supporting bar on the metal stand base, and then install the electrode clip on the
supporting bar.
Connect the power adapter
Plug the power adapter tightly into the DC9V socket. The power’s voltage should meet the requirements listed
on the power adapter.
Things needed in addition to what’s included in the box
A clean cup, distilled water (8-16oz), and tissue papers for rinsing and drying the probe.
5.2 pH Electrode Information
pH Electrode
The meter comes with the 35419-31, 3-in-1 combination electrode with a built-in temperature sensor, which
enables the automatic temperature compensation. This electrode is suitable for regular water solutions’ pH
testing. Please refer to Section 7 for ideal pH electrodes to use for other specific applications. The electrode’s
housing adopts polycarbonate materials, which is resistant to shocks and corrosion. A 3M KCL storage bottle
comes with the electrode, which is for storing the electrode when not in use to keep the sensitivity of the probe.
Figure - 6

- 6 -
Technical Specifications of the 201T-F pH Electrode
Measurement Range: 0 - 14 pH, 0 - 80˚C (32 – 176˚F)
Junction: Single Ceramic
Reference Electrode: Ag/AgCl
Connector: BNC
Size: ø12*160 mm
Temperature unit: 30K Thermistor
Electrode Connectors
The pH electrode has two connectors: the BNC connector connects the pH probe; the RCA connector connects
the temperature sensor. Plug these two connectors into ‘pH/mV” and “TEMP” sockets. Please note not to pull
the cables in case of poor contact. Please keep the connectors clean and dry. Refer to section 4.7 regarding
how to properly maintain the pH electrode.
Use the Electrode
Screw off the KCL storage bottle, and put it aside (do not dump or spill the KCL solution). Prepare a cup of
distilled water, and rinse the electrode in it for a few seconds. Gently shake the probe to remove excess water,
and dry it with clean tissue paper (DO NOT rub or wipe the probe, just use paper to dap off excess water).
Gently stir the electrode for a few seconds after it’s dipped into the test solution and then let it stand still. Wait
for the stable measurement (a smiley face appears and stays) and then record the readings. When test is
finished, place the electrode in the storage bottle and tighten the cap in order to keep the sensitivity of the pH
sensor.
5.3 Information regarding Calibration
pH buffer solutions
The meter has 2 series of standard buffer solutions: USA and NIST (see Table-2). They can be selected
in parameter P1 (see 4.6.1).
Table-2
Calibration icon
pH standard buffer series
USA
NIST
3-Point
calibration
1.68 and 4.00 pH
1.68 and 4.01 pH
7.00 pH
6.86 pH
10.01 pH
9.18 pH
3-Point Calibration
The meter can adopt 1 to 3 points of calibration. The 1st point must be using 7.00 pH (or 6.86 pH) buffer
solution, and then choose other buffers to do 2nd point and 3rd point. Please refer to Table-3 for details. In
the process of calibration, the slope of acidity range and alkalinity range will be displayed, which indicates
the health of your probe. The closer the slope is to 100%, the better the condition of the probe is.

- 7 -
Table-3 Calibration Mode
USA
NIS
Calibration
icon
When to adopt
1-Point
Calibration
7.00 pH
6.86 pH
accuracy≤ ±0.1 pH
2-Point
Calibration
7.00 pH and
4.00/1.68 pH
6.86 pH and
4.01/1.68 pH
Measuring range: 0 to 7.00 pH
7.00 pH and 10.01 pH
6.86 pH and 9.18 pH
Measuring range: >7.00 pH
3-Point
Calibration
7.00pH, 4.00/
1.68 pH and 10.01 pH
6.86pH, 4.01/
1.68pH, 9.18 pH
Wide measuring range
How often to calibrate
The frequency that you need to calibrate your meter depends on the tested samples, condition of
electrodes, and the requirement of the accuracy. For High-Accuracy meaustements (≤ ±0.02pH), the
meter should be calibrated before test every time; For ordinary-accuracy measurements (≥±0.1pH), once
calibrated, the meter can be used for several days before recalibration. In the following cases, the meter
must be re-calibrated:
a) The electrode hasn’t been used for a long time or a new electrode is connected.
b) After measuring strong acid (pH<2) or strong base (pH>12) solutions.
c) After measuring fluoride-containing solution and strong organic solution
d) There is a significant difference between the temperature of the test sample and the temperature of
the buffer solution that is used in the last calibration.

- 8 -
5.4 pH Meter Calibration
1) Press to enter calibration mode. CAL1 icon will flash in the upper
right corner of the LCD. 7.00 pH will flash in the lower right corner of the
LCD, reminding you to use pH 7.00 buffer to conduct 1st point of
calibration.
2) Use distilled water to rinse off electrode and then dry it (with a tissue).
Dip it into pH 7.00 buffer solution, stir gently and let it stand still and wait
for the reading to become stable. In the lower right corner of LCD, the
process of auto recognizing the buffer solution will be displayed. Pressing
before the buffer is recognized will generate Er2 (please refer to
table 5).
3) When the meter locks 7.00 pH in the lower right corner, stable
icon displays on LCD. Then press key to calibrate the meter.
End icon appears after calibration is done.
The 1st point calibration is finished. In the meanwhile, CAL2 will flash at
the upper right corner, and 4.00 pH & 10.01 pH will flash alternately at the
bottom right, indicating using pH4.00 or pH10.01 buffer solution
to make the 2nd point calibration.
4) Take out the pH electrode, rinse it in distilled water, dry it, and dip
it into pH 4.00 buffer solution. Stir the solution gently and let stand still in
the buffer solution until a stable reading is reached. The meter’s display
will show the recognition process of calibration buffer solution at the lower
right corner. When the meter recognizes 4.00 pH, stable icon
displays on LCD. Press key to calibrate the meter. End icon and
electrode slope of acidity range will be displayed after calibration is done.
In the meanwhile, CL3 will flash at the upper right corner of the LCD, and
10.01 pH will flash at the lower right, indicating using pH10.01 buffer
solution to make the 3rd point calibration.
5) Take out pH electrode, rinse it in distilled water, dry it, and dip
it into pH 10.01 buffer solution. Stir the solution gently and let it stand still
in the
buffer solution until a stable reading is reached. The meter’s display will show
recognition process of calibration buffer solution at the bottom right of
LCD. When the meter recognizes 10.01 pH, stable icon displays on LCD. Press
key to calibrate the meter. End icon and electrode slope of alkalinity range
display after calibration is done. The meter returns to the measurement mode, the calibration icons L M
H will be displayed. Please see Figure-7 for the above calibration process.
Figure-7