Yoke P611 User manual

Shanghai Yoke Instrument Co.,Ltd.
Model P611 pH Meter
Operation Manual

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Table of Contents
1. Brief Introduction -----------------------------------------------------------------------------------
2. Technical Parameters -------------------------------------------------------------------------------
3. Instructions to the Meter ---------------------------------------------------------------------------
3.1. LCD Display -------------------------------------------------------------------------------------
3.2. Operation Keys ----------------------------------------------------------------------------------
3.3. The Storage, Recall and Elimination of the Measuring Information ---------------------
4. pH Measurement ------------------------------------------------------------------------------------
4.1. Preparation Work --------------------------------------------------------------------------------
4.2. Meter Calibration --------------------------------------------------------------------------------
4.3. Sample Test --------------------------------------------------------------------------------------
4.4. Parameter Setting --------------------------------------------------------------------------------
4.5. Considerations -----------------------------------------------------------------------------------
4.6. The Self-diagnose Information ----------------------------------------------------------------
5. mV Measurement -----------------------------------------------------------------------------------
6. Meter’s Complete Kit -------------------------------------------------------------------------------
7. Warranty ----------------------------------------------------------------------------------------------
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1. Brief Introduction:
Thanks for buying and using the model P611 pH/mV Meter (the following called “meter”in
short).
Before using this meter, please read the operation manual carefully in order to help use and
maintain it correctly. On the basis of improving instrument of performance constantly, we
reserve the right of changing the content of this manual and accessories in case of not
notifying in advance.
This meter is a perfect combination with the most advanced electronic technology, sensor
technology and software design The meter can measure the parameters of pH, mV and
temperature for high accuracy solution. It is the best portable pH meter with the highest
performance and the lowest cost. It is suitable for the trade such as the mining industry,
power plant, water treatment projects and environmental protection, etc., especially has
more extensive application in the field and spot test.
Built-in microprocessor chip, beautiful appearance, multi-functional and easy to use, this
meter has the following prominent features:
1.1. Built-in microprocessor chip, with the intelligent functions of automatic calibration,
automatic/manual operation temperature compensation, data storage, function setting
and automatic self-diagnose, auto power off and low voltage display etc. Equips with
calibration solution and special carrying case, easy to use.
1.2. Adopts digital filter and step slipping technology to intelligently improve meter’s
response speed and result accuracy. “ ” will appear when reading to be stable.
1.3. A new type of pH meter electrode and temperature electrode,the pH measurement
mode has the function of automatic temperature compensation ,it is more convenient
to use, more accurate to measure.
1.4. Automatically recognize 15 kinds of pH standard buffer solution. User can choose
anyone from three series of buffer solutions: Europe & U.S.A. series, NIST series, and
China series,can be a point, two and three points to calibrate the way to facilitate
customer selection.
1.5. Meter’s circuit board adopts SMT film-covering technology to improve meter’s
production reliability.
1.6. Meter has the back light LCD display monitor.
1.7. IP54 dust and water resistant.

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2. Technical Parameters:
2.1. pH:
Measuring range
(-2.00 - 19.99) pH
(Depending on type of electrode used)
Resolution
0.1/0.01 pH
Accuracy
Meter:±0.01pH; Complete Kit: ±0.02pH
Input current
≤2×10-12 A
Input impendance
≥1×1012 Ω
Stability
±0.01 pH/3h
Temp. Compensation range
(0 - 100) ℃(auto/manual)
2.2. mV:
Measuring range (mV/ORP/EH)
-1999 mV - 0 - 1999mV
Resolution
1mV
Accuracy
Meter:±0.1% FS
2.3. Other Technical Parameters:
Data storage
150 groups
Storage content
Series number, measuring value, measuring
unit and temperature
Power
Two AA batteries (1.5V x2)
Size and weight
Meter: (165×90×32)mm/310g
Quality and safety certification
ISO9001:2000, CE and CMC
2.4. Working Condition:
Environment temperature
5 - 35 ℃(0.01 grade)
Environmental humidity
≤85%
IP rating
IP54 dust and water resistant.

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3. Instructions to the Meter:
3.1. LCD Display:
① —— Parameters mode icon
② —— Measuring value
③ —— Serial number and icon as measuring value to be stored and recalled.
M+ —measuring value to be stored icon;
RM —reading to be recalled icon;
④ —— Measuring unit
⑤ —— Temperature measuring value and unit
⑥ —— Measuring value to be stable icon
⑦ —— Electrode calibration indicate icon

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⑧ — — Indication icon of low voltage, appears when the voltage less than 2.4V, call
attention to change the batteries.
3.2. Operation Keys:
The meter has 7 operation keys in all.
3.2.1. —Switch key
In the measurement mode open and shutdown function , other mode keys do not work.
3.2.2. —Calibration key
(a) When in the measurement state, press this key to enter into calibration mode.
(b)When in the non - measurement state, the key is returned as the exit key.
3.2.3. —Function key
When in the measuring state，Short-time press (time≤1.5s) ，cyclic changing unit:
→
3.2.4. —Back light and Data deleting key
(a) When in the measuring state, short press (less than 1.5s) to open or close the back
light display;
(b) When in the storage record query state,long press (more than 5s) delete save data.
3.2.5. —increase and query key, —reduce and save key
(a)When in the measuring state, short press (≤1.5s), save measure data,
Short press (≤1.5s),resume shows the save data
(b) When in the parameter setting state, and change parameter size
3.2.6. —The entrance key and return key

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(a) When in the measuring state, long press (≥2s)this key to set parameter.
(b) When in the non-measuring state,short press (≤1.5s), determine current selection.
3.3. The Storage, Recall and Elimination of the Measuring Information:
3.3.1. Store the measuring information:
In the measuring mode, when the measuring data is stable and appear the “ ”,
short-time press key(less than 1.5s),LCD will display “M+ ”icon and storage
serial number, and meanwhile memory all the measuring information. Meter can storage
100 groups data(Two different units altogether storage 150 groups data)
3.3.2. Recall measuring information:
(a) Under the measuring mode, short press the key (≤1.5s),meter will recall the
last stored information, and the storage number and “RM”icon and the complete
measuring information will appear in the lower right corner of the LCD. Again press
and key, meter will in turn recall all the measuring information
(b) In the recalling state，press key will return the measurement mode
3.3.3. Eliminate the stored measuring information:
In the recalling mode, depress the key for 5 seconds, LCD will appear “ ”
for 2 seconds. It means the storage has been eliminated, and returns to measuring mode.
4. pH Measurement:
4.1. Preparation Work:

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4.1.1. Press key to turn on，press key, select PH measurement mode
4.1.2. Check E-201pH composite electrode,check pH composite electrode glass bulb
whether or not keep wet,if the glass bulb damaged,the electrode cannot be used,if glass
bulb’s surface too dry need to be immerged into a saturated potassium chloride
solution for 24 hours to activate and reuse.
4.1.3 Insert the PH composite electrode and the temperature electrode into the
corresponding interface.
4.2. Meter Calibration:
4.2.1. Press to enter into calibration mode, LCD displays the twinkling “ ”
indicate to enter into the first point calibration.
4.2.2. Wash the pH electrode in purified water and dry it, then immerge it into the pH 7.00
buffer solution, rock the electrode holder and then still, waiting for the data stable and
appear “ ”, then again press key , the LCD will appear a twinkling 7.00
pH, confirm the calibration is right then press key to confirm the first point,
the “ ” will appear in the upper right corner,prompt into the second point
calibration or press key exit calibration mode.
4.2.3. Wash the pH electrode in purified water and dry it, then immerge it into the pH4.00
buffer solution, rock the electrode holder and then still, waiting for a stable data and
appear “ ”, then again press key , the LCD will appear a twinkling
4.00pH, confirm the calibration is right then press key to confirm the second
point ,the “ ” will appear in the upper right corner,prompt into the third point
calibration or press key exit calibration mode.
4.2.4. Wash the pH electrode in purified water and dry it, then immerge it into the pH 10.01
buffer solution, rock the electrode holder and still, waiting “ ” for the data stable and appear,

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then again press key , LCD will appear a twinkling 10.01 pH, confirm the calibration
is right then press key to confirm the third point, at this time exit calibration mode into
measuring mode ,the LCD will appear “ ” in the lower left corner,it means
meter was third times calibrated.
4.2.5. Note:
(a) This meter can adopt random one-point, two-point or three-point automatic calibration,
after the first point calibration (see item 4.2.2.), press to exit calibration
mode and enters into measuring mode. The indication icon “ ” for
one-point calibration will appear on the lower left corner of LCD. When the
measuring accuracy is ≤±0.1pH, user just need to choose one kind buffer solution
to take one-point calibration according to the measuring range.
(b) After the second point calibration, (see item 4.2.3.), press to exit calibration
mode and enter into measuring mode. The indication icon “ ” for
tow-point calibration will appear on the lower left corner of LCD. User can choose
pH4.00 and pH 7.00 to calibrate if the measurement is just within the acidity range and
choose pH7.00 and pH 10.01 to calibrate if just within the alkalinity range.
(c) User should choose three-point calibration so as to reach a more accurate
measurement if the measuring range is wide, or if the electrode has been used for long
or has ageing phenomenon. As to the new electrode which be used for the first time, it
must be calibrated by three-point calibration to keep the unanimity of the meter slope
adjustment with the pH electrode.
4.3. Sample Test:
Immerge pH electrode into the sample solution after washing and dry it, rock the
electrode holder and still, when the LCD appears the icon “ ” to take the reading

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after displaying value to be stable.
Note: According to the pH equal temperature measuring theory: the closer the
temperature of the sample solution with the calibration solution, the more accurate
the measuring value will be acquired. So please comply with this theory.
4.4. Parameter Setting:
4.4.1. pH parameter schedule (Chart (4-1))
Chart (4-1)
Prompt
Mark
Parameter Setting Items
Parameters
P1
Manual temperature
compensation setting
(0-99.9)℃
P2
Resolution selection
0.1pH/0.01pH
P3
pH standard buffer solution
selection
CH、USA、NIST
P4
Temperature unit setting
℃ ℉
P5
Purified water,Ammonia
added purified water pH
restitution
OFF-ON
P6
Backlight timing shutdown
time setting
(0-20)m/0 means closes this
function
P7
Auto power off setting
(0-20)m/0 means closes this
function
P8
Restore to producer setting
OFF-ON
4.4.2. Manual temperature compensation settings(P1)
(a) Depress key enter into setting mode,press enters into P1 mode: see
picture (4-2).
(b) Press or key to change the temperature value;
Long press the two settings keys can be changed quickly;

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Press key determines the current settings and returns.
(c) Press key to enter into next parameter setting or press key to return
to measuring mode.
4.4.3. Resolution selection (P2)
(a) Press key in the mode P1 choose P2 , press key enters into mode
P2, see picture (4-3).
(b) Press or to choose resolution :
0.1→0.01;
Press key determine the choice.
(c) Press key to enter into next parameter setting or press key to
return to measuring mode.
4.4.4. pH standard buffer solution selection (P3)
(a) press key in mode P2 to choose mode P3,press key enters into
mode P3 see picture (4-4).
(b) Press key or change buffer solution selection;there are Europe &
U.S.A series,NIST series and China series;press key determines the current
settings and returns;
(c) press key enter into next parameter setting or press key to
return to measuring mode.
Three series standard buffer solution values:
CH(China series): 1.68ph 4.00ph 6.86ph 9.18ph 12.46ph
NIS(NIST series):1.68ph 4.00ph 6.86ph 9.18ph 12.46ph
USA(Europe & U.S.A series):1.68ph 4.00ph 7.00ph 10.01ph 12.46ph

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4.4.5. Temperature unit ℃/℉setting (P4)
(a) Short press key in mode P3 to choose mode P4,press key enters into
P4 see picture (4-5).
(b)Press or key to choose temperature unit: ℃or ℉,press key
determines and returns;
(c) Press key to enter into next parameter setting or press key return to
measuring mode.
4.4.6.Purified water，Ammonia added purified water pH restitution(P5)
(a) Press key in mode P4 to choose mode P5,press key enters into P5 see
picture (4-6).
(b)Press key and key modified, " OFF "no compensation," H2O "Purified
water pH compensation;" nH3 "ammonia added purified water compensation;
(c)Press key to enter into next parameter setting or press key return to
measuring mode.
4.4.7. Back light display time setting (P6)
(a) Press key in mode P5 to choose mode P6,press key enters into P6
see picture (4-7).
(b) Press and key to choose the time of back light auto power off,press

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key determines and returns;
(c) Press key to enter into next parameter setting or press key to
confirm and return to measuring mode.
4.4.8. Auto power off time setting (P7)
(a) Press key in mode P6 to choose mode P7,press key enters into P7 see
picture (4-8).
(b)Press or key to choose the auto power off time,press key
determines and returns; " 0"means to shut off auto power function;
(c)Press key to enter into next parameter setting or press key return to
measuring mode.
4.4.9. Restore to producer setting (P8)
(a) Press key in mode P7 to choose mode P8,press key enters into P8 see
picture (4-9).
(b)Press or key to choose “ON ”, then press key
determines,“888 ”flicker means restore to producer setting; press key
return to measuring mode.
（c）This function is used carefully. Once the factory setting is restored, the data that is
stored before the calibration will be deleted.
4.5. Considerations:
4.5.1. Calibration times of meter rely on the sample, electrode performance and required
accuracy. For high accurate measurement ( ≤±0.02pH), which should be calibrated
immediately with high accurate standard buffer solution, for general accuracy
measuring ( ≤±0.1pH), which can be used almost one week or long time once be

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calibrated.
4.5.2. The meter must be re-calibrated in the following situations:
(a) New changed or unused electrode for a long time;
(b) After measuring acid (pH<2) or alkaline (pH>12) solution;
(c) After measuring solution which contains fluoride and concentrated organic solution;
(d) The solution’s temperature is much different with calibration temperature.
4.5.3. The soaking solution in the protecting bottle of front pH electrode is to keep the glass
bulb and junction activating. Loose the capsule, pull out the electrode and wash it in
purified water before measuring. Insert the electrode and screw tight the capsule after
measuring to prevent the solution leaking. If the soaking solution is turbid or moldy,
please wash and change a new one at once.
4.5.4. The preparation of the soaking solution: take 25g analytical pure KCL, dissolved with
purified water and dilute to 100mL. Electrode should avoid soaking in purified water
protein solution and acid fluoride solution for a long time as well avoid getting
touching with organic silicon lipidic matters.
4.5.5. To calibrate the meter with the given value pH buffer solution, the pH value of the
standard buffer solution must be reliable so as to improve the accuracy. Buffer
solution should be changed in time after many times using.
4.5.6. Always keep the meter clean and dry; especially for the socket of meter and electrode,
otherwise it may lead to an inaccurate measurement or invalidity. To clean and dry
them with medical cotton with dehydrated alcohol if there are any dirty.
4.5.7. The sensitive glass bulb in the front of combination electrode should not touch with
hard things, any broken and rough will make the electrode invalidity. Before and after
measuring, the electrode should be washed with purified water, and dry electrode
after washing, don’t clean glass bulb with tissue for it will effect stability of electrode
potential and enlarge response time. The electrode should be washed many times for

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removing the sample stuck on the electrode, or wash with suitable solvent then clean
the solvent with purified water after measuring sticky sample.
4.5.8. An electrode be used for a long time, or measured solution which contains a polluting
solute easily for the sensitive bulb, or a substance resulting in jam at the junction, the
electrode will be getting passivated, its sensitivity will decrease and its response is
getting slow, the reading are not correct. It could adopt the following method for
various cases:
(a) The glass bulb is contaminated and aging: Put the electrode into 0.1mol/L dilute
hydrochloric acid (Preparation: diluted 9mL hydrochloric acid to 1000mL with
purified water) for 24h. Rinse it with purified water, then dipped it into the electrode
dipping solution for 24h. If the passivation is serious, then user can also put the bulb
of electrode into 4% HF (hydrofluoric acid) or the electrode activation solution for 3
to 5 seconds, rinsing it with purified water, and dipped it in the electrode soaking
solution for 24h to renew it.
(b) Wash for contaminated glass bulb and junction: (For reference)
Contamination Abluent
Inorganic metal oxide diluted acid less than 1mol/L
Organic lipidic matter dilute washing (weak alkaline)
Resin macromolecule matter dilute alcohol, acetone, ether
Proteinic haematocyte sediment Acidic enzymatic solution (such as dried yeast)
Kinds of paint dilute bleacher, peroxide
4.5.9. pH electrode using period is about 1 year, but its life will be shortened if using condition
is poor or incorrect maintenance. So it should be replaced immediately after electrode
become aging or invalid.
4.5.10. When it appears an abnormal reading when calibration or displaying, please set P8 as

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“ON”to restore the meter to producer setting mode, and then to calibrate and
measure again.
4.6. The Self-diagnose Information:
When using, there might appear the following icons. This is the meter’s self-diagnose
information, which can help to know some information about the meter or the electrode
when using:
4.6.1. The stable icon -2.00 pH or the 19.99 pH —this icon appeared when the value has
surpassed the measuring range. There will also appear such signs when the electrode
is not well connected with the meter or when the electrode is not immerged into the
solution. This is a normal phenomenon.
4.6.2. “ ” —Electrode zero potential to be exceeded (<-60mV or >60mV)
4.6.3. “ ” —Electrode slope to be exceeded (< 50% or >105%)
When appear “ ” or “ ”, the meter can not work, please take the
following check:
(a) Check if the electrode bulb has air bubble, if has, please shake it hardly.
(b) Check the quality of buffer solution, if it goes bad or the value has biggish error.
(c) Set the meter to producer setting mode (for details see P12 item 4.4.9.), then
re-calibrate it.
If still can not recover the normal state after doing the above checking, please replace a
new pH electrode.
5. mV Measurement:
5.1. Press key to turn on, and short press switch to mode;
5.2. Connect the ORPC composite electrode or the ion composite electrode (sold separated),
the electrode is washed and dried in pure water and immersed in the measured
solution., slowly stir and then still. When there appear a “ ” and a stable

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reading, that is the value.
6. Meter’s Complete Kit:
6.1. Model P611 pH meter
6.2. E-201-9 combination electrode
6.3. T-10-Q temperature electrode
6.4.standard buffer solution（4.00,7.00,10.01）
6.5. Manual
6.6. Carrying case
7. Warranty:
7.1. We warrant this meter to be free of charge maintain, replace the parts or products under
normal using circumstances, from purchased time within one year caused by
manufacturing bad and unable to work.
7.2. Attached electrodes do not belong to this warrant range. But, if the newly purchased
electrode went wrong without using, it’s free of charge to maintain and replace.
7.3. The above warranty is not apply to defects resulting from action of user such as misuse,
improper wiring, operation outside of specification, improper maintenance or repair, or
unauthorized modification.
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