SATO KEIRYOKI SK-660PH Series User manual

Instruction Manual
SK-660PH Series pH Meters
No. 6428-00 Model SK-660PH
No. 6429-00 Model SK-661PH
No. 6430-00 Model SK-662PH
3-4, Kanda-kajicho, Chiyoda-ku, Tokyo 101-0045 Japan
URL: http://www.sksato.co.jp/english/

1
Introduction
Thank you for purchasing the pen type SK-660PH series pH meters.
- These pH meters are designed to measure hydrogen ion concentration (pH) and liquid
temperature. Do not use it for any other purposes
- Read this instruction manual thoroughly before using the instrument and store it in a safe place.
Warning
DANGER
RISK OF EXPLOSION
- These instruments are not explosion-proof. Never use them in environment with flammable
gases.
- For any inquiries, contact the store where you bought the instrument or our service network.
Cautions
Follow the instructions below when using the instrument.
- These are precision instruments. Be careful not to drop or knock it.
- Operating this instrument outside the temperature range may result in unit malfunctions. Make
sure to use the unit within the operating temperature range specified in this manual.
- Avoid using this unit in a place exposed to direct sunlight or near a heat source. Otherwise,
the unit may become deformed or malfunction.
- If this instrument is left in a car under the hot summer sun, it will become extremely hot and may
malfunction. Do not leave the unit in such a place.
- If this unit is used in an environment where electrical noise is generated, the display may
become unstable or the measurement error may increase.
- Never disassemble or modify the unit. Doing so may cause malfunctions.
- Always remove the batteries if the unit is not in use for a long period of time. Otherwise, the
batteries may leak, resulting in malfunctions.
- Do not dispose of used batteries in a fire.
- Keep the batteries out of the reach of children. If accidentally ingested, consult a doctor
immediately
- Do not wash or wipe this unit with alcohol, thinner, or other solvents. Use soft cloth to clean.
In case of tough stain, wipe it with a cloth that that has been soaked in water with a neutral
detergent and tightly wrung.

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- Do not let the pH standard solution in touch with skin or clothes.Wash off under running water if
the solution got on skin. In case the solution got into an eye, wash it off immediately and consult
a doctor.
- Keep the pH standard solutions out of reach of children. If accidentally ingested, consult a
doctor immediately.
Overview
The SK-660PH series pH meters are portable pen type pH meters that are designed for easily
measuring hydrogen ion concentration (pH) and liquid temperature.
Features
⚫Washable waterproof type (In compliance with the IPX5 grade of the JIS C 0920)
* IPX5: Water projected by a nozzle against enclosure from any direction shall have no
harmful effects.
⚫Portable, pen-type body
⚫Sensor sensitivity display function
By checking the sensor deterioration state, it is east to check the sensor maintenance and
replacement periods.
⚫Stability displaying function
It is possible to know the measured value is stabilized with this function.
⚫Auto temperature compensation function
It is possible to measure more accurate pH value with this function.
⚫1 to 3 pH calibration points setting
Selectable the most suitable calibration points (at 25°C) among 4.01, 6.86, 9.18 or 10.01.
⚫Replaceable sensors
⚫Auto power-off
The power is turned off automatically after 20 minutes. This will prevent the battery
consumption when forgotten to turn off the power.
Precautions:
- Check that the instrument has not been damaged during transport. If damage is found, contact
the store where you bought the instrument or our service network.

3
Names of components
1. Main body
(1) Display : Displays measurement readings or status of the unit.
(2) SET/ key : Power ON/OFF switch
(3) CAL/ /▽key : Enters the calibration mode. When the calibration mode is on, use it to
modify the set value.
(4) HOLD/△key : Holds the value being displayed. When the calibration mode is on, use it
to modify the set value.
(5) Nut for sensor fixture (9) Glass sensor cover
(6) Glass electrode (10) Battery cover
(7) Temperature sensor (11) Sensor cap
(8) Liquid junction
2. Details of the display
(12) pH reading
: Measured pH value is displayed here.
(13) Temperature reading
: Measure temperature value is displayed here.
(14) pH measuring indication
: This indication lights up when the measured
value is stable.
(* Turn to ‘Stability displaying function’ section
for more details.)
(15) CAL indication : This indication blinks when calibration mode is on.
(16) HLD indication : This indication light up when a measured value is being held (HOLD).
(17) Low Battery indication : This indication blinks when the battery power is low.
8
7
6
5
4
3
2
1
9
10
11
12
13
14
15
16
17

4
Installing and replacing the batteries
Please install or replace batteries when using the unit for the first time or the low battery
indication blinks by the instructions as follows:
(1) Turn the battery cover counter-clockwise to loosen the cover.
(2) Remove old batteries when replacing the batteries.
(3) Install the batteries by referring to the polarity marks on the
battery compartment.
(4) Reinstall the cover in the reverse steps to loosen the cover and
tighten it.
Caution
- Immediately replace the batteries with new ones if the display is flashing. Otherwise the
measurement accuracy may be affected or malfunction may occur
- Securely tighten the battery cover. If not tightened enough, the unit’s waterproof property will no
longer be effective. Before tighten the cover, make sure that the seal is free from dust or dirt.
When dirty, clean it before tightening.
- Do not try to remove the battery cover if the surface of the unit body is wet or there are water
drops on it. Water may enter inside the unit to cause malfunctions.
- For environmental protection, dispose of used batteries in compliance with local rules and
regulations.
Before measuring
Within the glass electrode cover, there is phthalates standard solution filled to prevent the glass
electrode from drying out. Remove the glass electrode cover when taking measurements. After
measurement, put the cover back on for storage.
Cautions: When the unit is first used or after it has been stored for several days, the pH
measurement response may be slower. In such cases, immerse the sensor terminal
in either the pH standard solution or water and let it stand for one hour (for more
accurate measurement, at least 12 hours in the standard solution) before use. Do
not turn on the unit during this immersion time.

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* How to remove the glass electrode cover
Grab the both sides of the opening area of the
sensor part with your fingers, and turn the sensor
counter-clockwise to remove the sensor from the
unit.
Cautions: When set or remove the glass electrode cover, be careful not to spill the phthalates
standard solution inside the cover. Make sure the solution does not in touch with skin
or clothes. Wash off under running water if the solution got on skin. In case the
solution got into an eye, wash it off immediately and consult a doctor.
* If the solution is spilled, refill the cover with fresh phthalates standard solution to prevent the
electrode from drying. Using distilled, pure or tap water is also effective.
<Auto Power-Off Function>
Auto Power-off function is activated when none of the keys were operated for about 20 minutes.
Turn this function off if constant measurement is required.
⚫Disabling the auto power-off
Press the HOLD/△key and SET/ key simultaneously to turn on the unit. The "n" character
appears on the display to indicate the auto power-off function is disabled.
Caution
Disabled auto power-off function is no longer effective when the unit gets turned off. Disable
the auto power-off function each time the power is turned on.
<Calibration mode>
Better precision of pH measurements is expected when the unit is calibrated. It is recommended
to have daily calibration of the unit.
Please prepare followings prior to calibration.
● Standard solutions
Item
Standard solution
pH value (at 25°C)
pH4
Phthalates standard solution
4.01
pH7
Neutral phosphate standard solution
6.86
pH9 or pH10
Borate or carbonate standard solution
9.18 or 10.01
● Water (distilled, pure or tap water)
● Beakers (Have same number of beakers as number of calibration points)

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It is recommended to have number of beakers with water according to the kinds of standard
solutions mentioned above.
* Various types of pH standard solutions are available as optional products. For details, contact
the store where the instrument was purchased or our service network.
⚫About calibration points
Calibration points can be selected based on the intended usage of the unit. Please refer to
following for calibration points.
Points
Intended use
3 points
For pH characteristics of measuring sample
2 points
To figure out whether measuring sample is acid or alkaline.
- Acid : pH4 and pH7 (2 points)
- Alkaline : pH7 and pH9 or pH10 (2 points)
1 point
To measure pH value of a sample simply
Standard solution close to sample (1 point)
⚫Calibration method
(1) Press the SET/ key to turn on the unit.
(2) Remove the sensor cap and the glass electrode cover, and then wash the glass electrode
thoroughly with water (distilled, pure or tap water). Absorb the water drops on the glass
electrode by using clean filter paper, cotton swabs or tissue paper.
Caution: Be careful not to rub the glass electrode. Doing so may build up static electricity,
causing unstable pH values.
(3) Immerse the glass electrode in the standard solution. Do not move the unit until the ‘pH’
indication change from blinking to light up.
Caution: Calibration of the unit cannot be performed if the ‘pH’ indication does not change
from blinking to light up. In this case, pH standard solution or the sensor itself
might be degraded. If new pH standard solution does not improve the problem,
replacement of sensor is necessary. Refer to ‘Sensor Replacement’.
(4) Press the CAL/ /▽key for two seconds. The ‘CAL’indication and pH value blink and the
mode switches to calibration mode.
This instrument automatically displays following initial values after determining pH standard
solution.
● SK-660PH / SK-661PH ●SK-662PH
Item
Initial value
Measuring range
Item
Initial value
Measuring range
pH4
4.0
3.0~5.0
pH4
4.01
3.00~5.00
pH7
6.9
6.0~8.0
pH7
6.86
6.00~8.00
pH9 or pH10
10.0
8.5~11.0
pH9 or pH10
10.01
8.50~11.00

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Cautions: In case the initial values change in order, pH standard solution or the sensor
itself might be degraded. If new pH standard solution does not improve the
problem, replacement of sensor is necessary. Refer to ‘Sensor Replacement’.
(5) Press the HOLD/△key or CAL/ /▽key to adjust the pH calibration value to that of the
standard solution.
* In order to more accurate measurement, adjust the calibration temperature to the sample
temperature.
● Relationship between pH and temperature
Standard
solution
Name of solution
Liquid Temp.
pH value
Liquid Temp.
pH value
pH4
Phthalates
0°C
4.00
30°C
4.02
5°C
4.00
35°C
4.02
10°C
4.00
40°C
4.04
15°C
4.00
45°C
4.05
20°C
4.00
50°C
4.06
25°C
4.01
-
-
pH4
Neutral phosphate
0°C
6.89
30°C
6.85
5°C
6.95
35°C
6.84
10°C
6.92
40°C
6.84
15°C
6.90
45°C
6.83
20°C
6.88
50°C
6.83
25°C
6.86
-
-
pH4
Borate
0°C
9.46
30°C
9.14
5°C
9.40
35°C
9.10
10°C
9.33
40°C
9.07
15°C
9.28
45°C
9.04
20°C
9.22
50°C
9.01
25°C
9.18
-
-
pH4
carbonate
0°C
10.32
30°C
9.97
5°C
10.24
35°C
9.92
10°C
10.18
40°C
9.89
15°C
10.12
45°C
9.86
20°C
10.06
50°C
9.83
25°C
10.01
-
-
Excerpt from the JIS Z 8802-1984(2006)
* No calibration using oxalic acid standard solution (pH1.68 at 25°C) can be performed.

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(6) When the calibration value is set, hold the set value until the "SA" indication appears on the
display in about 30 seconds.
(7) The “SA” indication is on display for 2 seconds and the value is stored in the unit. After that
the display returns to the pH value display mode.
(8) Clean the glass electrode with distilled, pure or tab water.
(9) In case other calibration points are to be calibrated, repeat the steps from (3).
pH Measurement
(1) Turn on the unit by pressing the SET/ key. The display lights up all indications for about
one second and the measurement mode begins.
(2) Remove the sensor cap and glass electrode cover.
(3) Immerge the electrode into a sample 3cm in depth.
(4) Make sure the measure value is stable (“pH” indication lights up when stable) before reading
the value.
* Stable display function
When the pH value is stable, the ‘pH’ indication changes from blinking to light up. Please
refer to ‘Stable display function’ for more details. Unstable measured value can occur
depending on samples to be measured. In that case, use HOLD function to measure and
read the value.
(5) Press the SET/ key to turn off the unit after measurement is complete. Clean the glass
electrode in distilled, pure or tab water and store.
Caution
- The glass electrode of this unit may be degraded or its useful life may be shortened if it is
used in liquids such as organic solvents, oils, adhesives, strong acids (pH 0 to pH 2), strong
alkalis (pH 12 to pH 14) and surface-active agents.
- The measured value may be unstable when pure water is subject to measure.
- When measuring drinks, pour the liquid in a different container where measureable depth of
3cm can be obtained. Do not drink what is leftover of the sample after measuring.
- The sensor part is made of glass. Please make sure to treat it carefully. In case of damage to
the glass part, be careful not to get injured from broken glass.
<HOLD function>
The HOLD function may be useful when the measured value is unstable during taking
measurement.
(1) Press the HOLD/△key in the measurement mode. The ‘HLD’ indication will light up and the
measured value will be held.

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(2) Press the HOLD/△key once again to disable this function. The ‘HLD’ indication will blink
and the value will not be held any more.
<Stability Displaying function>
This unit allows the ‘pH’ indication from blinking to light up to indicate that the values are stable
when following conditions are met:
Conditions for Stability Display
Model
Conditions
SK-660PH
Change in 10 seconds : ±0.1pH or ±0.5°C
SK-661PH
SK-662PH
Change in 10 seconds : ±0.05pH or ±0.5°C
Note: This function cannot be disabled. Measure values may be unstable with samples such as
pure water, however this is not malfunction of the instrument.
Individual settings
Following setting are available in measurement mode:
Model
Conditions
Sensitivity of pH sensor is displayed.
* In between pH4 and pH7
Sensitivity of pH sensor is displayed.
* In between pH7 and pH9 or pH10
Asymmetric potential difference (mV) is displayed
Switching temperature unit (°C or °F)
Reset
⚫How to operate setting mode
(1) With the unit off, press the SET/ key for 2 seconds to turn the power on and the unit will
switch to the setting mode.
(2) Press the CAL/ /▽and the display will switch the modes in following steps below:
SL1 → SL2 → OFF → unit →rSt → Setting mode
<Sensitivity Displaying Function SL1 / SL2 / OFF>
The instrument displays the sensitivity of the sensor and asymmetric potential difference based
on the data of the calibration time. These thresholds may be used as a reference for setting the
sensor maintenance and replacement time.

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* Sensitivity
The pH glass sensor generates an asymmetric potential difference occurs by the pH value of a
sample. Sensitivity can be calculated by the comparison between this difference and theoretical
value, and a percentage deviation from the theoretical value is displayed. ‘100.0’ is displayed
when the sensitivity is ‘100.0%’, meaning the difference is equivalent to the theoretical value.
* Asymmetric potential difference
The internal solution of pH 7 has been sealed in the internal electrode. When measuring the
solution of pH7, the asymmetric potential difference theoretically should be ‘0’, however the
strain of the sensor or the state of the glass film may occur, causing some potential differences,
and this difference is called asymmetric potential difference. The difference could be large by
contaminated electrode and internal solution, dehydration, and degrade, causing errors. The
unit for asymmetric potential difference is mV. When the displays shows ‘-10.0’, it means that
the ‘asymmetric potential difference is -10.0mV’.
(1) Switch to SL1 in the setting mode. The sensitivity (%) between pH4 and pH7 will be
displayed.
(2) Switch to SL2. The sensitivity (%) between pH7 and pH9 or pH10 will be displayed.
(3) Switch to OFF. The asymmetric potential difference (mV) will be displayed.
* The degradation of sensor is assumed by the device when the sensitivity is below 75% or
above 115%, or the asymmetric potential difference is above ±60mV. (Error code [E13])
<Reset ' rS't>
This procedure will reset all stored calibration values to the preset values and temperature unit
to °C.
(1) Switch to ‘rSt’ in the setting mode. ‘No’ in the lower part of the display will blink.
(2) Press the HOLD/△key to switch the ‘No’ indication to ‘YEs’ then press the CAL/ /▽to
confirm. The display will switch to the measurement mode after the reset is completed.
Sensor replacement
The degradation of the sensor may cause malfunctions such as disabling of calibration or
changes in displayed values immediately after a calibration.
When such malfunctions occur, refer to ‘Trouble Shooting’ section for solutions.
Replace the sensor with a new one according to following steps:
(1) Remove the sensor cap and the nut for sensor
fixture by turning the nut counter-clockwise.

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(2) Pull off the sensor straight up from the unit.
(3) Refer to the drawing below as a guidance to put
the new sensor to the unit.
(4) Turn the nut for sensor fixture clockwise to tighten.
(5) Perform calibration after sensor replacement.
Caution
- Seal the nut for sensor fixture tightly. If not sealed enough, the unit’s waterproof property will
no longer be effective. Before tightening the cover, make sure that the seal is free from dust or
dirt. When dirty, clean it before sealing.
- Do not try to remove the nut for sensor fixture if the surface of the unit body is wet or there are
water drops on it. Water may enter inside the unit to cause malfunctions.
About the glass electrode
(1) Storage method
Accurate pH measurement shall not be expected when the glass sensor is dry. The
appropriately moisturized glass electrode can measure and display the normal values.
Immerge the sensor in phthalate pH standard solution or distilled, pure or tab water when
storing.
* When the unit is used for the first time after its purchase or after it has been stored for
long period of time, immerse the sensor in either pH standard solution or distilled, pure or
tab water for at least 12 hours, then calibrate the unit before pH measurement.
(2) Testing / Calibration
Use pH standard solution to measure pH values in order to have the accurate pH
measurements. In case any errors in value as a result of the tests, perform calibration
before pH measurement.
Caution: Use new pH standard solution
(3) Cleaning
Always use distilled, pure or tab water to clean the glass electrode after a pH calibration or
pH measurement. If not cleaned, the measured solution could create a film over the
surface of the electrode, compromising the measurements.

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(4) Usage life
The glass electrode is consumable. The usage life may differ by types, pH values and
temperature of measured samples.
(5) Deposit of white potassium chloride crystal
A deposit of white crystal is sometimes found on the tip of the glass electrode; this does not
pose a problem when using the instrument, and the deposit is easily washed off with tap
water. If it does not come off with tap water, soak the glass electrode in warm water to
remove it.
Caution: Do not lick or swallow the potassium chloride crystal. If the eyes or skin becomes
contaminated with the crystal, immediately wash it off with water and consult a
doctor.
Error messages
An error code appears on the display when an error occurs.
Category
Code
Details
Solution
Temperature
E 02
The measured value went
over the measureable range.
Use the device within the
measureable range.
If the problem remains, contact the
distributor or our service network.
E 03
pH
E 02
The measured value went
over the measureable range.
Use the device within the
measureable range.
There is a possibility of degradation
or failure of the sensor. If the problem
remains after cleaning the sensor,
replace it with a new one.
E 03
E 04
Abnormal operation of auto
temperature compensation
occurs.
Use the device within the
measureable range.
If the problem remains, there may be
an error with the sensor.
E 13
Sensor sensitivity or
asymmetric potential
difference goes beyond the
calibration range.
(1) The calibration may have failed.
Recalibrated the instrument.
(2) The sensor may be degraded or
malfunctioning. If the problem
remains after cleansing the
sensor, replace it with a new one.
Others
Error in electronic parts of the
main unit occurs.
Please contact the distributer where
purchased or our network.

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Trouble Shootings
Type of trouble
Possible cause
Solution
Unstable measured
values
The sample amount is not
enough.
Immerge the sensor into the sample
3cm deep from the distal end of the
sensor.
The sample may have low
conductivity such as pure water.
Due to the characteristics of the
glass sensor measurement,
samples with low conductivity may
show unstable readings.
The temperature of the sample
may be changing.
Stabilize the temperature of the
sample.
Probable abnormal
measured values
The glass electrode may be
dirty.
Clean the glass electrode.
(Refer to the 'About the glass
electrode' section)
The glass electrode may be dry.
The glass electrode is broken.
Replace the sensor with a new one.
No calibration was performed.
Perform a calibration.
The sample amount is not
enough.
Immerge the sensor into the sample
3cm deep from the distal end of the
sensor.
The measured sample
temperature and the
temperature during calibration is
significantly different.
Recalibrate the unit at close
temperature to the sample
temperature.
If above measures do not improve the situation, a probable sensor
degradation or failure is suspected. Please replace the sensor with a
new one.
Calibration failure
The sensor may be degraded.
Replace the sensor with a new one.

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Specifications
Product name
Pen type pH meter
Model
SK-660PH
SK-661PH
SK-662PH
Cat. No.
6428-00
6429-00
6430-00
Measuring
range
pH
2.0~12.0pH
0.0~14.0pH
0.00~14.00pH
°C
0.0~50.0°C
Accuracy
pH
±0.3pH
±0.2pH
±0.05pH
°C
±1.0°C
±0.5°C
Resolution
pH
0.1pH
0.01pH
°C
0.1°C
Measuring sampling
Approx. 1 second
Waterproof property
JIS C 0920「IPX5」
Measuring ambient
0 to 50°C, less than 80%rh (no condensing)
Storage ambient
-10 to 50°C (no condensing)
Power Requirement
Alkaline Batteries LR44 × 4 pc.
Battery Life
Approx. 200 hours continuous usage.
Materials
Case ：ABS resin
Electrode ：Glass
Dimensions
Approx. ø38×(L)171mm
Weight
Approx. 82g (with batteries)
Standard accessories
Instruction manual, Alkaline battery LR44x 4 pc. one wrist strap
Optional products
Product name
Model
Cat. No.
Replacement sensor
660S
6431-00