AZIN PHS-550 Technical manual

OPERATION MANUAL
OPERATION INSTRUCTION
PHS-550
High accuracy digital pH meter
1. Unpacking & Accessory
2. Specifications
3. Operation
4. Maintenance and notice
5. Configuration of standard solution

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1. Unpacking & Accessories
PHS-550 pH Meter 1PC
Combination PH electrode 1PC
Short circuit plug in the back of Meter 1PC
Electrode Stand 1PC
Temperature Sensor 1PC
9V Adaptor 1PC
Buffer Solution pH4.00, pH6.86, pH 9.18 1PC/EACH
User Manual 1PC

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2. Specifications
Mode PHS-550
Range pH：0～14.00pH
mV:±1999mV，
Temp：0～100℃
Resolution pH：0.01pH，
Temp：±1℃
Accuracy pH：0.01pH，Te m p：±1℃
Temperature compensation 0－100℃automatic compensation
Three points calibration 4.00, 6.86 and 9.18
Basic configuration E201-C plastic case PH combination electrode
(Temperature of solution 5-60℃be suitable)
PH sample standard solution
DC9V adapter
Working condition
zAmbient temperature：0～40℃Relative humidity：＜85％
zPower：9V DC power
zNo significant vibration
zNo disturbance of magnetic field or distinct tremble around instrument.
zInput resistance: ≥1×1012Ω
zZero drift:≤0.01pH±1word／2 hours
zSolution temperature compensation range:5~60℃
zDimension and weight:230x200x60mm,1.2KG

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3. Operation
Preparation
zInsert the adapter into the 220V AC power supply; after that, insert the dc output plug
into "DC9V" socket. Screw off the short circuit plug of the meter, Screw on the pH
electrode. Please keep clean and dry of electrode before using, avoid to be polluted.
zSwitch on the instrument and preheat for 5 minutes.
Calibration
zBefore measurement, the instrument should be calibrated. To be accurate, the
calibration should be conducted by using the standard solution of pH4.00, 6.86, and
9.18.
zConnect power, and press on/off key to turn on the instrument.
zMake sure the pH combination electrode is screwed on, the sensor should be
cleaned by purified water and no remained water.
zMeasure the temperature of pH buffer solution by thermometer; then, press the key
of “∧” or “∨” to adjust the temperature to be same as the buffer solution.
zPoint calibration: Immerse the pH electrode into pH6.86 solution, shake it for a while,
then wait until the number shows on the screen is stable, keep pressing the
"calibration" key until the screen show the "CAL", first “6.86” twinkles, few seconds
later shows the: “END”, then shows the calibrated pH value. It indicates that the
calibration is completed and stored. Please note the final calibrated pH value shows
on the screen may be different under different temperature. For example, it will show
pH6.86 under 25℃and pH6.90 under 15℃. Details please find it from the last page.
zSlope calibration I: Take out the pH electrode, clean it by purified water and make it
dry, immerse the pH electrode into PH4.00 solution, shake it for a while then wait until
the number shows on the screen is stable, keep pressing the "calibration" key until
the screen show the "CAL", it shows 4.00 first, few seconds later shows the "END",
then shows the final pH value, which indicates the calibration is completed and be
stored. When finish calibration, the slope percentage will be adjusted automatically.
Please note the final calibrated pH value shows on the screen may be different under

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different temperature. For example, it will show pH4.00 under 25℃and pH4.02
under 35℃. Details please find it from the last page.
zSlope calibration Ⅱ: Take out the pH electrode, clean it by purified water and make it
dry, immerse the pH electrode to PH9.18 solution, shake it for a while then wait until
the number shows on the screen is stable, keep pressing the "calibration" key until
the screen show the "CAL", it shows 9.18 first, few seconds later shows the "END",
then shows the final pH value, which indicates the calibration is complete and be
stored. When finish calibration, the slope percentage will be adjusted automatically.
Please note the final calibrated pH value shows on the screen may be different under
different temperature. For example, it will show pH9.18 under 25℃and pH9.28
under 15℃. Details please find it from the last page.
Solution measurement
zMeasure the temperature of solution by thermometer, then press increase key "∧" or
decrease key "∨" adjust the temperature value, clean the pH electrode and immerse
it to the tested solution, shake it for a while then place until reading comes stable,
that is the PH value of the tested solution.
Notice: According to the isothermal measurement principle, for the temperature of tested
solution and calibration solution, the closer, the more accuracy of the test result.
zMV value measurement:
Press "PH/MV" key, shift the instrument to "MV" display,
Connect ORP electrode and immerse them into the tested solution, shake for a while
then place it until the measure value is stable, that is the ORP value of the tested solution.

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4. Maintenance and note
Notes for Testing Sample
zThe electrode plug and socket of instrument must keep clean and dry, short circuit
plug should be put on when not using, for preventing the intrusion of dust and
moisture.
zThe different sample should use the suitable pH electrode(for example: measure
strong acid、strong alkali or pure water and so on.
zThe lead-in wire of electrode must keep static when test the sample, don't touch it
with hand, otherwise it will cause the measurement instability.
zThe preparation standard solution must use the twice distilled water or Non-Ion water,
its conductivity should be less than 2μs/cm.
zThe standard buffer solution should be stored in the refrigerator (low temperature
around 5-10℃), it can preserve for 2-3 months. If there is muddy, mildew or sediment
in the solution, please do not use any more.
zDon't use the standard buffer solution which passed the shelf life, don't pour the used
standard buffer solution into the standard solution bottle with unused solution.
zUse the standard buffer solution which approach the pH value of sample if possible
when in calibration, and the standard solution temperature is better the same with
sample if possible.
zIt would be best to turn off and calibrate again if need to replace the electrode when
use the instrument.
Notes for electrode use
zCombination electrode is not supposed to immersed into distilled water for a long
time, it should be inserted into the bottle which is filled with the electrode protect
solution
zThe configuration of electrode protect solution: take one pocket of pH4.00(250ml),
soluble in the 250ml ion water, then add 56g analytically pure KCL, stir until
completely dissolved.
zAvoiding to let the top of electrode being knocked after remove the protect cover of

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electrode, otherwise the electrode will not work if the top glass ball of electrode is
broken.
zWhen using liquid chargeable electrode, please note that if liquid inside decreases to
be less than half volume, please use burette to add liquid from hole at the top. When
measuring, please turn the blue circle to cover the small hole.
zWhen electrode moves from one solution to another solution, it should be cleaned by
distilled water and dried by filter paper. Do not wipe the glass ball to avoid sluggish
response. The best method is washing electrode by the next test solution.
zAvoiding that the bubble cut off the reference solution inside the electrode, if it exists,
please eliminate it by shaking off the electrode.
zPlease reduce the immerse time when testing the strong acid and alkali or special
solution (like: protein, paint and so on), after testing, wash it carefully.
zThe slope and response time of electrode will be decrease a little after long time
using, please immerse the electrode ball for 24hours into 0.1 mol/L HCL solution
(preparation: 9ml HCL diluted to 100ml by Non-Ion water).
Common Problem Checking
zMost problems are due to electrode functional problem or wrong measurement, not
the instrument. Besides, buffer solution and other factors will lead to some problems,
please check carefully, and find out what exactly the problems are.
Electrode
If the instrument is operating well, but the reading is unstable, instrument responds slowly,
or cannot be calibrated to the right pH value, please check electrode first as below:
1. Whether electrode sensor inserts into testing liquid or not
2. There are no bubbles inside electrode
3. Electrode ball is not polluted
4. Electrode and instrument are well connected, and lead wire is not loose or broken.
Standard buffer solution
If the instrument and the electrode is operating well, the readout is not correct or cannot
be calibrated, please check the standard buffer solution:
1. Use the exact standard pH buffer solution.
2. The buffer solution is under quality guarantee period and not be polluted.

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5. Preparation of standard solution
Pour the standard solution powder into the 250ml beaker, use the distilled water to wash
it, and then dissolved and diluted to the scale, then shake up.
Below is the pH value and temperature relation table:
pH solution
Solutionvalue name
Tem p ℃
0.05mol/kg
potassium
hydrogen phthalate
0.025mol/kg
phosphate mixture
0.01mol/kg
borax
0℃4.01 6.98 9.46
5℃4.00 6.95 9.39
10℃4.00 6.92 9.33
15℃4.00 6.90 9.28
20℃4.00 6.88 9.23
25℃4.00 6.86 9.18
30℃4.01 6.85 9.14
35℃4.02 6.84 9.10
40℃4.03 6.84 9.07
45℃4.04 6.83 9.04
50℃4.06 6.83 9.02
55℃4.07 6.83 8.99
60℃4.09 6.84 8.97
70℃4.12 6.85 8.93
80℃4.16 6.86 8.89
90℃4.20 6.88 8.86
95℃4.22 6.89 8.84