Environmental Express 100 Series User manual

100 Series Portable pH/Cond. Meter
Instruction Manual
pH 100 portable pH Meter
EC 100 portable conductivity Meter
PC 100 portable pH/Cond. Meter
Environmental Express
www.environmental express.com

Table of Contents
1 BRIEF Introduction........................................................................................................................... - 1 -
1.1 Measuring parameters .............................................................................................................. - 1 -
1.2 Features and functions.............................................................................................................. - 1 -
1.3 Features of measuring parameters............................................................................................. - 2 -
2 Technical Specifications ................................................................................................................... - 2 -
2.1 Parameter specifications ........................................................................................................... - 2 -
2.2 Other specifications .................................................................................................................. - 4 -
3 Instrument Desctiption.................................................................................................................... - 4 -
3.1 LCD display ............................................................................................................................... - 4 -
3.2 Keypad functions ...................................................................................................................... - 5 -
3.3 Meter sockets ........................................................................................................................... - 6 -
3.4 Display mode and other functions ............................................................................................. - 6 -
3.5 Other functions......................................................................................................................... - 7 -
4 pH Measurement ............................................................................................................................ - 8 -
4.1 pH electrode information .......................................................................................................... - 8 -
4.2 Calibration solution and calibration mode.................................................................................. - 8 -
4.3 pH measurement ...................................................................................................................... - 9 -
4.4 pH test.................................................................................................................................... - 10 -
4.5 Information regarding pH calibration and measurement .......................................................... - 10 -
4.6 Customized calibration (take 1.60pH & 6.50pH as example)...................................................... - 11 -
4.7 Notes regarding customized calibration ................................................................................... - 11 -
4.8 Self-diagnosis information....................................................................................................... - 11 -
4.9 Maintenance of the pH Electrode ............................................................................................ - 12 -
5 mV and ORP Measurement............................................................................................................ - 13 -
5.1 mV measurement ................................................................................................................... - 14 -
5.2 ORP measurement.................................................................................................................. - 14 -
6 Conductivity Measurement............................................................................................................ - 15 -
6.1 Conductivity electrode information ......................................................................................... - 15 -
6.2 Information about conductivity calibration.............................................................................. - 16 -
6.3 Conductivity calibration (take 1413 μS/cm as an example) ....................................................... - 17 -

6.4 Relation between TDS and conductivity................................................................................... - 18 -
6.5 Sample test............................................................................................................................. - 18 -
6.6 Conductivity electrode maintenance ....................................................................................... - 19 -
7 Parameter setting.......................................................................................................................... - 20 -
7.1 Main menu of parameter setting ............................................................................................. - 20 -
7.2 Sub-menu of pH parameter setting.......................................................................................... - 21 -
7.3 Sub-menu of ORP parameter setting........................................................................................ - 22 -
7.4 Sub-menu of conductivity parameter setting ........................................................................... - 22 -
7.5 Sub-menu of basic parameter setting....................................................................................... - 24 -
8 What’s in the Kit?.......................................................................................................................... - 25 -
9 Warranty....................................................................................................................................... - 25 -

- 1 -
1 BRIEF INTRODUCTION
Thank you for purchasing Environmental Express 100 series Portable pH/Cond. Meter (hereafter
referred to as the instrument). The instrument is an outstanding combination of the most advanced
electronic technology and software design.
Before using the product, please read this manual carefully to help you properly use and maintain
the product. Environmental Express reserves the right to update the content of this manual without
giving prior notices.
1.1 Measuring Parameters
Measuring Parameters
pH100
EC100
PC100
pH
√
√
mV/ ORP
√
√
Cond./TDS/Salinity
√
√
Temperature
√
√
√
1.2 Features and Functions
⚫The built-in microprocessor chip enables advanced functions such as auto
calibration, auto temperature compensation, parameter setting, self-diagnosis,
auto power-off, low-battery reminder, etc. PC100 meter can measure pH &
conductivity at the same time. See diagram on the right, pH electrode,
conductivity electrode and the temperature probe can be installed on the clip
for simultaneous measurements.
⚫The meter adopts advanced digital processing technology, intelligently
improves the response time and accuracy of the measurements. Stable reading
and auto lock display mode are available for choice.
⚫Meets IP57 waterproof and dust resistant rating, ideal for use under harsh
environment.

- 2 -
1.3 Features of Measuring Parameters
Measuring
Parameter
Features
Applicable
Model
pH
● 1~3 points auto calibration with calibration guide & self-diagnosis function.
● Automatic recognition of pH calibration solutions: USA, NIST & CUS (user-
defined).
pH100
PC100
mV
With temperature measurement and display function.
pH100
PC100
ORP
With ORP calibration function
pH100
PC100
Cond.
● 1~ 4 points auto calibration with calibration guide and auto-check function.
● Automatic recognition of conductivity calibration solutions: Standard & CUS
(User-defined).
● Single-tap switch among conductivity, TDS and Salinity.
EC100
PC100
2 TECHNICAL SPECIFICATIONS
2.1 Parameter Specifications
Technical Parameters
Applicable
Models
pH
Range
0.00 ~ 14.00pH
pH100
PC100
Resolution
0.01/0.1 pH
Accuracy
±0.01 pH
Temperature
compensation
range
0 ~ 100°C (Auto or manual)
Calibration
1~3 points auto calibration
Buffer solutions
USA, NIST
mV
Measuring
Range
±1000mV
pH 100

- 3 -
Resolution
-200 ~ 200mV: ±0.1mV
Other range: ±1mV
PC 100
Accuracy
±0.2% F.S.
ORP
Range
±1000mV
pH 100
PC 100
Resolution
1mV
Accuracy
±0.2% F.S.
Calibration
Range
±50mV of reading
Conductivity
Measuring
Range
0~200 mS/cm, including 5 ranges:
0.00~19.99μS/cm, 20.0~199.9μS/cm, 200~1999μS/cm,
2.00~19.99mS/cm, 20.0~199.9mS/cm
EC 100
PC 100
Resolution
0.01/0.1/1μS/cm, 0.01/0.1 mS/cm
Accuracy
±1.0% F.S.
Temperature
compensation
range
0 ~ 60°C (Auto or manual)
Electrode
Constant
0.1 / 1 / 10 cm-1
Temperature
coefficient
0~9.99%/°C
Reference
temperature
15~30°C
Calibration
1~4 points automatic
Calibration
solutions
84μS/cm, 1413μS/cm, 12.88mS/cm, 111.8mS/cm
TDS
Range
0~100g/L
EC 100
PC 100
Accuracy
±1.0% F.S.
Salinity
Range
0~100ppt
EC 100
PC 100
Accuracy
±1.0% F.S.
Temperature
Range
0~100°C
pH 100
EC 100
PC 100
Resolution
0.1°C
Accuracy
±0.5°C ±1digit

- 4 -
2.2 Other specifications
Power
AA batteries x 3 (1.5V×3)
IP rating
IP57 waterproof and dust resistant
Dimension &
Weight
Meter: 91×190×33mm, (3.58”x7.48”x1.29”) / 342 gm
Carrying case: 330×270×82mm, (12.99”x10.63”x3.22”) / 0.59 kg
Paper box: 255×200×45mm, (10.04”x7.87”x1.77”) /1.28 kg
3 INSTRUMENT DESCRIPTION
3.1 LCD display
①
Measuring mode icon
⑦
ATC—Automatic temperature compensation
MTC—Manual temperature compensation
②
Measurement reading
⑧
Calibration indicator icon
③
Units of measurement
⑨
Auto. Hold icon of reading
④
Temperature units
⑩
Stability icon of reading
⑤
Indicator icon
⑪
Low battery icon
⑥
Temperature value and
indicator icon

- 5 -
3.2 Keypad functions
Short press ----- <2 seconds; Long press ----- >2 seconds.
Table - 1 Keypad operations and descriptions
Keypad
Operations
Descriptions
Short press
⚫Press to turn on or turn off the meter.
Short press
Long press
⚫Press to select parameter or unit:
pH100 pH meter: → → ；
EC100 conductivity meter: → →
PC100 pH/cond. meter: → → → → →
⚫Long press to enter the menu of parameter setup
Diagram - 1

- 6 -
3.3 Meter sockets
The meter sockets are protected by silicon caps, waterproof and dustproof, open the silicon caps
and connect the meter with the electrode.
Table - 2 Meter sockets
Model
Remarks
pH100
BNC socket (left) —connect pH electrode or ORP electrode
Φ2.5 socket (middle)—connect temperature probe
EC100
BNC socket (right)—connect conductivity electrode
Φ2.5 socket (middle)—connect temperature probe
PC100
BNC socket (left)—connect pH electrode or ORP electrode
Φ2.5 socket (middle)—connect temperature probe
BNC socket (right)—connect conductivity electrode
3.4 Display mode and other functions
3.4.1 Stable Reading Mode
When the measurement value is almost stable, smiley icon
appears on LCD, see Diagram - 2. If the smiley icon does not
appear or flash, please do not get the reading value or conduct
Long press
Short press
⚫In measurement mode, long press to enter calibration mode.
⚫Press to cancel operation, the meter returns to measurement mode or
the previous interface.
⚫When the measure value is locked-up, short press release lock-up.
Short press
⚫In measurement mode: press to turn on/off the backlight.
⚫In calibration mode: press to calibrate.
⚫In the parameter setup mode: press to enter and open the sub-menu,
confirm parameter.
Short press
Long press
⚫Under MTC (see Section 3.4.4), short press to change temperature, long
press for quick changing of the value.
⚫In parameter setup mode: press to select parameter.
Diagram - 2

- 7 -
calibration until the measuring value is stable.
3.4.2 Automatic Lock-up Display Mode
Select on from parameter P6.2 to turn on automatic lock-up
display function. When the reading value stabilizes more than 10
seconds, the meter locks the reading value automatically and
Displays HOLD icon, see Diagram - 3. In HOLD mode, press
to release lock-up. Diagram - 3
3.5 Other functions
3.5.1 Manual Temperature Compensation
When temperature probe is not connected, press or to change the temperature value,
long press for quick changing of the temperature value.
3.5.2 Automatic Power-off
The meter is with automatic power-off function. Select from parameter P6.4 to select automatic
power-off time: 10-20-30-off, i.e. user can select automatic power-off time to be 10 minutes, 20
minutes or 30 minutes (starting from the last operation). When Off is selected, the meter will not
turn off automatically.
3.5.3 Back-light
The meter is with white backlight, suitable for application even in dark environments. However,
when backlight is on, the consumption of the power will increase. Press to turn on/off the
backlight in measurement mode. Select from P6.3 to select lasting time for backlight: 1-2-3-Off, i.e.
select backlight lasting time to be 1 minute, 2 minutes or 3 minutes. When Off is selected, the
backlight will be turned on all the time.
3.5.4 Battery
The meter adopts 3xAA batteries. Please use LR6 alkaline battery to
ensure the battery quality. Battery life > 200 hours (without backlight).
When LCD displays icon, please replace with new batteries, see
Diagram - 4. Diagram - 4

- 8 -
4 PH MEASUREMENT
4.1 pH electrode information
4.1.1 The meter connects to 201-C plastic combination pH electrode, with BNC connector.
Configured with MP500-2.5 temperature probe (built in 30kΩthermistor), Phono plug. The
meter can use other pH combination electrodes with the BNC connector.
4.1.2 When both the pH electrode and the temperature probe are connected to the meter, it
directly goes to automatic temperature compensation mode. When the meter is
connected to the pH electrode only, it will enter manual temperature compensation mode.
Press or to input the temperature into the meter.
4.1.3 Gently stir the pH electrode for a few seconds after it’s dipped into the test solution to
eliminate air bubbles for the stable measurement in a short period of time.
4.2 Calibration solution and calibration mode
4.2.1 Calibration solution
The meter is capable of calibrating up to 5 pH values using USA or NIST buffer series, corresponding
to calibration indicator icons, see Table - 3.
Table - 3 pH buffer solution series
Calibration icon
pH buffer solution series
USA
NIST
3 points
calibration
1.68 or 4.00 pH
1.68 or 4.01 pH
7.00 pH
6.86 pH
10.01 or 12.45pH
9.18 or 12.45 pH
4.2.2 Calibration mode
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-4
for details.
Table - 4 Calibration mode
USA
NIST
Calibration
icon
When to adopt

- 9 -
1-Point
Calibration
7.00 pH
6.86 pH
Accuracy: ±0.1pH
2-Point
Calibration
7.00 pH→4.00 or 1.68pH
6.86 pH→4.01 or 1.68pH
Measuring range: 0
to 7.00 pH
7.00 pH→10.01 or 12.45pH
6.86 pH→9.18 or 12.45pH
Measuring
range: >7.00 pH
3-Point
Calibration
7.00pH→4.00 or
1.68pH→10.01 or 12.45pH
6.86pH→4.01 or 1.68pH→
9.18 or 12.45pH
Wide measuring
range
4.3 pH Measurement
4.3.1 The 1st point calibration
Rinse the pH electrode and the temperature probe in distilled or deionized water and allow it to dry,
long press to the enter calibration mode. CAL1 icon will flash in the bottom right corner of the
LCD, reminding you to use pH7.00 buffer to conduct the 1st point of calibration. Dip the pH electrode
and the temperature probe into pH7.00 buffer solution, stir gently and let it stand still and wait for
the reading to be stable. When the stable icon displays on LCD, press to finish 1st
point calibration, meter goes to measurement mode, the bottom left of LCD indicating .
4.3.2 The 2nd point calibration
Rinse the pH electrode and the temperature probe in distilled or deionized water, allow it to dry.
Long press to enter calibration mode. CAL2 icon flashes at the bottom right corner of the LCD,
reminding you to make the 2nd point of calibration. Submerge the electrodes into pH4.00 buffer
solution, stir the solution gently and allow it to stay in the buffer solution until a stable reading is
reached. The meter’s display will show scanning and locking process of calibration buffer solution
at the bottom right of LCD. When the meter locks 4.00pH, stable icon displays and stays on
LCD. Press to calibrate the meter. Electrode slope displays after calibration is done, the 2nd
point calibration finished, the meter goes to measurement mode, and the bottom left of LCD
indicates ..
4.3.3 The 3rd point calibration
Repeat the steps as per Section 4.3.2, use pH10.01 buffer solution, and complete the 3rd point
calibration. The bottom left of LCD indicates .

- 10 -
4.4 pH test
Rinse pH electrode in distilled or deionized water, allow it to dry, and submerge it in the sample
solution. Stir the solution briefly and allow it to stay in the sample until the value becomes stable
and icon appears on LCD, get the reading which is the pH value of the sample solution.
4.5 Information regarding pH calibration and measurement
4.5.1 During the process of calibration and measurement, submerge both the pH electrode and
the temperature probe into the solution to ensure automatic temperature compensation.
4.5.2 In calibration mode, press to exit.
4.5.3 The meter can conduct 1~3 points of calibration according to measurement requirements.
Refer to Table - 4 to check when to adopt.
4.5.4 During the process of calibration and measurement, the meter has self-diagnosis
functions, indicating information Er1~Er4, please refer to Table - 5 for relevant solutions.
4.5.5 The calibration frequency depends on the sample, electrode performance and accuracy
requirement. For high accuracy measurements (≤±0.03pH), the meter should be calibrated
before test every time. For ordinary accuracy measurements (≥±0.1pH), once calibrated,
the meter can be used for about a week or even longer.
In the following cases, the meter must be re-calibrated:
a) The electrode hasn’t been used for a long time or the electrode is brand new.
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 big difference between the temperature of the test sample and the
temperature of the buffer solution that is used in the last calibration.
4.5.6 pH temperature principle
Please note that the closer the temperature of the sample is to the calibration solution, the more
accurate will be the readings.
4.5.7 Factory default setting
The meter has a function to return to factory default setting, which can be set up in P1.3. All
calibration data will be deleted, and the meter will restore to the theory value (zero electrical
potential of pH is 7.00, the slope is 100%). Some functions restore to the default value (refer to
Appendix - 1). When calibration or measurement fails, please restore the meter to factory default
setting and then perform re-calibration or measurement. Please note once set the factory default,
all the data deleted will be irretrievable.

- 11 -
4.6 Customized calibration (take 1.60pH & 6.50pH as example)
4.6.1 Choose CUS (customized calibration) in parameter setting P1.1, the meter enters
customize calibration mode.
4.6.2 Rinse the electrode with distilled or deionized water, allow it to dry. Long press to
enter calibration mode, dip it into 1.60pH calibration solution, stir gently and let it stand
still and wait for the reading to become stable. When the smiley icon displays on LCD,
press to adjust the value to 1.60, then press to confirm the calibration.
The meter goes back to measurement mode, and the 1st point calibration is completed.
4.6.3 Dip the electrode into 6.50pH buffer solution, follow the steps as per Section 4.6.2 to
finish the 2nd point of calibration. The meter can conduct 1~2 points of customized
calibration.
4.7 Notes regarding customized calibration
4.7.1 Calibration indicator will NOT appear at the bottom left of the LCD for a customized
calibration.
4.7.2 The pH of “customized calibration”is the measurement under certain temperature. The
meter must calibrate and measure in the same temperature, otherwise it will be inaccurate.
The meter does not recognize customize calibration solutions.
4.8 Self-diagnosis information
Among the calibration and measurement procedure, the meter has self-diagnosis function,
indicating relevant information, see Table - 5.
Table - 5 Self-diagnosis information in pH measurement mode
Display
Icon
Contents
Checking
Press before measuring
value becomes stable.
Press when icon appears and stays.
Wrong pH buffer solution or the
buffer solution out of range.
1. Check whether pH buffer solution is correct.
2. Check whether the meter connects the
electrode properly.
3. Check whether the electrode is damaged.
During calibration, the measuring
value being unstable (≥3min).
1. Check whether there are air bubbles in glass
bulb.
2. Replace with a new pH electrode.
pH electrode zero electric potential
1. Check whether there are air bubbles in glass

- 12 -
out of range (<-60mV or >60mV)
Electrode slope<75%
bulb.
2. Check whether pH buffer solution is correct.
3. Replace with a new pH electrode.
4.9 Maintenance of the pH Electrode
4.9.1 Daily maintenance
The soaking solution contained in the supplied protective bottle is used to maintain hydration of the
glass bulb and liquid junction. Loose the cap, take out the electrode and rinse in distilled or deionized
water before taking a measurement. Insert the electrode and tighten the cap after measurements
to prevent the solution from leaking. If the storage solution is cloudy or moldy, rinse the bottle and
replace the soaking solution (The method to prepare, dissolve 26g KCl into 100ml distilled water).
Make sure the meter is dry and clean all the time, especially the sockets and connectors, or else it
may lead to measurement inaccuracy or invalid readings. Once contaminated, use medical cotton
and water free alcohol to wipe clean and allow it to dry.
*The electrode should NOT be soaked and stored in purified or distilled water, protein solution, acid
fluoride solution or organic lipids.
4.9.2 Calibration buffer solution
For calibration accuracy, the pH of the standard buffer solution must be reliable. The buffer solution
should be refreshed often, especially after heavy use.
4.9.3 Protect glass bulb
The sensitive glass bulb at the front of the combination electrode should not come in contact with
hard surfaces. Scratches or cracks on the electrode will cause inaccurate readings. Before and after
each measurement, the electrode should be rinsed with distilled or deionized water. Do not wipe
the glass bulb with tissue paper as it may lead to unstable electric potential of the electrode and
the slow response. If a sample sticks to the electrode or it's contaminated, the electrode should be
thoroughly cleaned with soap water and then rinsed with distilled water.
4.9.4 Renew glass bulb
Electrodes that have been used for a long period of time will become aged. Submerge the electrode
in 0.1mol/L hydrochloric acid for 24 hours, then rinse the electrode in distilled water, then
submerge it in the soaking solution for 24 hours. For serious passivation, submerge the bulb in the
pH soaking solution (sold separately) to renew it.

- 13 -
4.9.5 Clean contaminated glass bulb and junction (see Table - 6)
Table - 6 Clean contaminated pH glass bulb and junction
Contamination
Cleaning Solutions
Inorganic metal oxide
Dilute acid less than 1mol/L
Organic Lipid
Dilute detergent (weak alkaline)
Resin macromolecule
Dilute alcohol and ether
Protein hematocyte sediment
Acidic enzymatic solution (saccharated
yeast tablets)
Paints
Dilute bleacher, peroxide
The electrode housing is polycarbonate. Please avoid using detergents including perchloromethane,
trichloroethylene, diethylene oxide and acetone, as these solutions will dissolve the shaft material
and lead to passivation or failure of the pH electrode.
5 MV AND ORP MEASUREMENT
Press and switch the meter to mV and ORP mode. mV mode is to measure the electric potential
of the pH electrode or other ISE, with temperature measurement function; ORP mode is to measure
the potential of the ORP electrode, without temperature measurement function but with calibration
function. See below table for the difference of the 2 modes.
Table - 7 mV and ORP measurement mode
mV
ORP
Range
±1000mV
±1000mV
Resolution
±200mV: ±0.1 mV
Other: ±1 mV
±1 mV
Temperature
0~100.0℃
N/A
Accuracy
±0.2% F.S.
±0.2% F.S.
Application
Electric potential of the pH electrode and
other ISE
Electric potential of the ORP electrode
Calibration
N/A
±50mV of the measuring value

- 14 -
5.1 mV measurement
Connect the pH combination electrode (or other ion combination electrodes) and the temperature
probe, submerge into the solution, stir gently and let it stand still, wait for the reading to be stable
and LCD displays and then get the reading.
5.2 ORP measurement
5.2.1 ORP means Oxidation Reduction Potential. It is an important measurement indicator of the
oxidation and reduction potential of water solutions. The unit is mV.
5.2.2 ORP measurement does not require calibration. This is because ORP is a qualitative
measurement of the redox ability of a solution, it is a relative index, not a quantitative
calculation. Connect to the ORP combination electrode (sold separately), immerse into the
sample solution, gently stir and let it stand still. Wait for the reading to be stable and LCD
displays , and then get the reading.
5.2.3 In order to make the ORP reading more comparable with the reference values, user can
calibrate using ORP standard solutions. Rinse the ORP electrode in distilled or deionized
water and allow it to dry. Long press to enter calibration mode, dip the electrode into
the ORP standard solution with known value. Gently stir and let it stand still, wait for the
reading to be stable and LCD displays , and then get the reading. Press or ,
adjust it to the required value. The range that can be adjusted is ±50mV, then press
to calibrate. The meter returns to measurement mode.
5.2.4 ORP standard solution:
There are different ORP standard solutions on the market, for example: 222mV or 468mV ORP
standard solution, which are all applicable of the meter. ORP standard solutions can not only used
for the calibration of ORP meters, but also used to check whether the ORP meter works properly. If
the ORP meter has been calibrated, please restore the ORP calibration mode to factory default
setting before using ORP standard solution to check if the meter works fine. Select Yes in parameter
setting P2.1, and then test the ORP standard solution.

- 15 -
5.2.5 Clean and activate the ORP electrode
After the electrode has been used over a long period of time, the platinum surface will get polluted
which causes inaccurate measurement and slow response. Please refer to the following methods to
clean and activate ORP electrode:
(a) For inorganic pollutant, submerge the electrode in 0.1mol/L dilute hydrochloric acid for 30
minutes, then wash it in distilled water, then submerge it in the electrode storage solution for 6
hours.
(b) For organic or lipid pollutant, clean the platinum surface with detergent, then wash it in distilled
water, then submerge it in the electrode storage solution for 6 hours.
(c) For heavily polluted platinum surface on which there is oxidation film, polish the platinum surface
with toothpaste, then wash it in distilled water, then submerge it in the electrode storage solution
for 6 hours.
6 CONDUCTIVITY MEASUREMENT
6.1 Conductivity electrode information
6.1.1 The meter comes with conductivity electrode with BNC connector and temperature probe
(built-in 30kΩthermistor) with 2.5 mm Phono plug.
6.1.2 When both the conductivity electrode and the temperature probe are connected to the
meter, it directly enters automatic temperature compensation mode. When the meter is
connected to the conductivity electrode only, it will enter manual temperature
compensation mode. Press or to input the temperature into the meter.
6.1.3 Gently stir the conductivity electrode for a few seconds after it has dipped into the test
solution to eliminate air bubbles for the stable measurement in a short period of time.
6.1.4 Conductivity electrode constant
The meter matches conductivity electrodes of three constants: K=0.1, K=1.0 and K=10.0. Please refer
to Table - 8 for measuring range. Set constant in parameter setting P3.2, refer to Section 7.4.

- 16 -
Table - 8 measuring ranges of cell constants
Range
＜20 μS/cm
0.5 μS/cm~100 mS/cm
＞100mS/cm
Conductivity
electrode constant
K=0.1 cm-1
K=1.0 cm-1
K=10 cm-1
Standard solution
84μS/cm
84 μS/cm
1413 μS/cm
12.88 mS/cm
111.9 mS/cm
6.2 Information about conductivity calibration
6.2.1 Conductivity calibration solutions
The meter uses conductivity standard solution of 84 μS/cm, 1413 μS/cm, 12.88 mS/cm and 111.9
mS/cm. The meter can recognize the standard solution automatically, can perform 1~4 points
calibration. The calibration indication icons correspond to the four standard values ( icon
corresponds to two standards). See Table - 9.
Table - 9 Conductivity standard solution series
Indication
Icon
Calibration
Solution
Indication
Icon
Calibration
Solution
Indication
Icon
Calibration Solution
84 μS/cm
1413 μS/cm
12.88 mS/cm or 111.8 mS/cm
6.2.2 Calibration intervals
(a) The meter is calibrated before leaving the factory and can generally be used right out of the
package.
(b) Normally perform calibration per month.
(c) For high accuracy measurements or large temperature deviation from the reference temperature
(25°C), perform calibration per week.
(d) Use conductivity standard solution to check whether there is error. Perform calibration for large
error.
(e) For new electrode or factory default setting, perform 3-point or 4-point calibration. Choose closer
standard solution to the sample solution to perform 1-point or 2-point calibration.
6.2.3 Reference temperature
Reference temperature of factory default is 25°C. Other reference temperature can also be set for
range 15°C ~ 30°C. Select in parameter setting P3.3 and refer to Section 7.4.

- 17 -
6.2.4 Temperature coefficient
The temperature compensation coefficient of the meter setting is 2.0%/°C. However, the
conductivity temperature coefficient is different from solutions and concentration. Please refer to
Table - 10 and the data collected during testing. Set per parameter setting P3.4. and refer to Section
7.4.
Note: When the coefficient for the temperature compensation is set to 0.00 (no compensation),
the measurement value will be based on the current temperature.
Table - 10 Temperature compensation coefficient of special solutions
Solution
Temperature compensation coefficient
NaCl solution
2.12%/°C
5% NaOH solution
1.72%/°C
Dilute ammonia solution
1.88%/°C
10% hydrochloric acid solution
1.32%/°C
5% sulfuric acid solution
0.96%/°C
6.2.5 Avoid contamination of standard solution
Conductivity standard solution has no buffer. Please avoid being contaminated during usage. Before
submerging the electrode in standard solution, please wash the electrode and allow it dry. Please
do not use the same cup of conductivity standard solution repeatedly, especially for standard
solution of low concentration (84 μS/cm). The contaminated standard solution will affect accuracy.
6.3 Conductivity calibration (take 1413 μS/cm as an example)
6.3.1 Rinse the electrode in distilled or deionized water, allow it to dry, long press to enter
calibration mode, submerge it in 1413 μS/cm standard solution. Gently stir and let it stand
still until a stable reading is reached. The meter’s display will show scanning and locking
process of calibration buffer solution at the bottom right of LCD. When the meter locks 1413
μS, stable icon displays and stays on LCD. Press to finish calibration. The
meter returns to measurement mode and the bottom left of LCD indicates .
6.3.2 For multi-point calibration, please repeat the steps indicated in Section 6.3.1 until all the
calibrations are done. The meter can repeat calibration in the same calibration solution to
ensure better accuracy and repeatability of the reading.
6.3.3 Notes
(a) Er1 (see Table - 12) appears if press key before the stable icon displays on LCD.