Amprobe WT-20 User manual

Users Manual
• Mode d’emploi
• Bedienungshandbuch
• Manual d’Uso
• Manual de uso
WT-20
Conductivity TDS Meter

WT-20
Conductivity TDS Meter
Users Manual
July 2009, Rev.1
©2009 Amprobe Test Tools.
All rights reserved. Printed in China
English

Limited Warranty and Limitation of Liability
Your Amprobe product will be free from defects in material
and workmanship for 1 year from the date of purchase. This
warranty does not cover fuses, disposable batteries or damage
from accident, neglect, misuse, alteration, contamination, or
abnormal conditions of operation or handling. Resellers are not
authorized to extend any other warranty on Amprobe’s behalf.
To obtain service during the warranty period, return the product
with proof of purchase to an authorized Amprobe Test Tools
Service Center or to an Amprobe dealer or distributor. See Repair
Section for details. THIS WARRANTY IS YOUR ONLY REMEDY.
ALL OTHER WARRANTIES - WHETHER EXPRESS, IMPLIED OR
STAUTORY - INCLUDING IMPLIED WARRANTIES OF FITNESS FOR
A PARTICULAR PURPOSE OR MERCHANTABILITY, ARE HEREBY
DISCLAIMED. MANUFACTURER SHALL NOT BE LIABLE FOR ANY
SPECIAL, INDIRECT, INCIDENTAL OR CONSEQUENTIAL DAMAGES
OR LOSSES, ARISING FROM ANY CAUSE OR THEORY. Since some
states or countries do not allow the exclusion or limitation of an
implied warranty or of incidental or consequential damages, this
limitation of liability may not apply to you.
Repair
All test tools returned for warranty or non-warranty repair or
for calibration should be accompanied by the following: your
name, company’s name, address, telephone number, and proof of
purchase. Additionally, please include a brief description of the
problem or the service requested and include the test leads with
the meter. Non-warranty repair or replacement charges should be
remitted in the form of a check, a money order, credit card with
expiration date, or a purchase order made payable to Amprobe®
Test Tools.
In-Warranty Repairs and Replacement – All Countries
Please read the warranty statement and check your battery before
requesting repair. During the warranty period any defective test
tool can be returned to your Amprobe® Test Tools distributor
for an exchange for the same or like product. Please check the
“Where to Buy” section on www.amprobe.com for a list of
distributors near you. Additionally, in the United States and
Canada In-Warranty repair and replacement units can also be sent
to a Amprobe® Test Tools Service Center (see address below).

Non-Warranty Repairs and Replacement – US and Canada
Non-warranty repairs in the United States and Canada should be
sent to a Amprobe® Test Tools Service Center. Call Amprobe® Test
Tools or inquire at your point of purchase for current repair and
replacement rates.
In USA In Canada
Amprobe Test Tools Amprobe Test Tools
Everett, WA 98203 Mississauga, ON L4Z 1X9
Tel: 877-AMPROBE (267-7623) Tel: [phone]
Non-Warranty Repairs and Replacement – Europe
European non-warranty units can be replaced by your Amprobe®
Test Tools distributor for a nominalv charge. Please check the
“Where to Buy” section on www.amprobe.com for a list of
distributors near you.
European Correspondence Address*
Amprobe® Test Tools Europe
In den Engematten 14
79286 Glottertal, Germany
Tel.: [phone] - 0
*(Correspondence only – no repair or replacement available from
this address. European customers please contact your distributor.)

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1) Battery Cover
2) Lcd Display
3) Power / Set Key
4) Hld / Cal / Down Key
5) Mode / Up Key
6) Electrode Cover
7) Conductivity Reading
(unit: uS or mS ) or TDS
Reading (unit: ppt or
ppm)
8) Display temperature in
either degree Celsius or
degree Fahrenheit
9) Calibration Mode
Indicator
10) Freeze Display
11) Low Battery Indicator
POWER / SET - Power on/off, Enter setting mode
(push 2 sec), Enter while in setting mode.
MODE / q Key - Conductivity/TDS mode switch,
Roll up while in setting mode
HLD / CAL /p Key - Freeze display, Calibration
function, Roll down while in setting mode
WT-20 Conductivity TDS Meter

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CONTENTS
SYMBOLS.......................................................................... 2
UNPACKING AND INSPECTION ....................................... 2
INTRODUCTION ................................................................ 3
Features ........................................................................ 3
OPERATION....................................................................... 3
Auto Power Off ........................................................... 4
Setup ............................................................................ 5
Calibration Mode ........................................................ 7
Conductivity Calibration ............................................. 7
TDS Calibration ........................................................... 9
SPECIFICATION ................................................................. 10
MAINTENANCE AND REPAIR ........................................... 11
Battery Replacement .................................................. 12
TROUBLE SHOOTING ....................................................... 13
Appendix A .................................................................. 15
Appendix B .................................................................. 15
Appendix C .................................................................. 16

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SYMBOLS
Caution! Refer to the explanation in this Manual
Conforms to relevant Australian standards
Complies with European Directives
Do not dispose of this clamp meter as unsorted
municipal waste. Contact a qualified recycler for
disposal.

WARNING and PRECAUTIONS
• Do not make the air bubble adhere on the
electrode. That may cause inaccurate reading.
• Do not operate the meter in ammable liquid.
UNPACKING AND INSPECTION
Your shipping carton should include:
1 WT-20 meter
4 LR44 battery
1 Manual
If any of the items are damaged or missing, return
the complete package to the place of purchase for an
exchange.

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INTRODUCTION
Congratulations on your purchase of WT-20 Conductivity
TDS meter. A convenient instrument to measure water
conductivity, TDS and temperature.
Features
• IP65 Waterproof housing.
• Dual display with ATC (°C / °F switchable)
• Data hold to freeze display.
• Low battery indicator.
• Auto power off.
• One touch only for calibration.
OPERATION
1. Remove the electrode cover to expose the
electrode out.
2. Press “POWER” to power on. LCD will display
parameters (ex: tnr, tCo, tds, rAn) in turns and
then enter normal display.
3. The meter is default in auto-ranging status. Press
“MODE“ key more than 2 seconds can manually
select the range when the meter is in normal
measurement mode.
4. Set the temperature coefficient to the right value.
WT-20 is factory set to 2.1% per °C. if needed, see
P1.3 to set the temperature coefficient.
5. Select the normalization temperature. WT-20 is
factory set to 25 °C. See P1.2 to change it to 20 °C.
6. Rinse the probe with deionized or distilled water
before use to remove any impurities adhering
to the electrode. Soak the probe more than 30
minutes to clear up the lazy effect of probe if the
meter is stored for a long time.

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7. Dip the probe into the sample container. Make
sure no air bubbles trapped in the slot of the
probe. To remove air bubbles, give the probe
a gentle stir. Making sure the electrode tip is
submerged when you stir it.
8. Stir the probe gently in the sample to create a
homogenous sample. Allow a few seconds to reach
temp. equilibrium. Wait about 15 minutes can get
a stable reading.
9. The unit of conductivity will flash on the LCD to
indicate the meter is in measurement mode. When
the reading is stable, the unit will stop flashing.
(Fig1)
10. Press “HLD” to freeze display. “Hold” will appear
on the LCD. (Fig.2) Press “HLD” again to release.
11. TDS Measurement:
In measurement mode, press ”MODE“ to switch
to DS mode. The unit of conductivity are uS or mS.
The unit of TDS are ppm or ppt.
Set the TDS conversion factor to right value. The
factory default is 0.50 To change the TDS factors,
refer Appendix A.
12. Turn off the meter by pressing “POWER“ key.
Auto Power Off
This meter will shut off automatically 20 minutes of
inactivity. To disable the auto power off, pressing “SET“
+ “HLD” keys simultaneously while turning on the meter
until a “n” appeared on the screen and then release keys
to return to normal mode.(Fig.3)

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Setup
The advanced setup mode lets you customize your meter.
4 types parameter are available.
P1.0: temperature parameter setting (t)
P1.1: Change temperature unit (tUt)
P1.2: Normalization temp.(tnr)
P1.3: Temp. Coefficient (tCo)
P2.0: TDS factor setting
P2.1: Setting TDS factor (tds)
P3.0: Reset meter (rSt)
P3.1: Reset
P4.0: Review Calibration Info. (CAL)
P4.1: Review range 1 calibration information
P4.2: Review range 2 calibration information
P1.1: Change temperature unit (tUt):
1. When in measurement mode, press “SET“ more
than 2 sec to enter setup mode. Press “q“or “p“
to select P1.0, press “SET“ to enter or press “SET“
for more than 2 seconds to quit.
2. Press “p“ to select C or F.
3. Press “SET“ to confirm or press “SET“ more than 2
sec to return to P1.0 without saving.
P1.2: Normalization temp.(tnr):
After saving temp. unit, the meter will automatically
enter normalization temp. adjustment. Press “p“ to
change the temperature to 20°C or 25°C. Press “SET“
to confirm and or press “SET“ more than 2 sec to
return to P1.0 without saving.

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P1.3: Temp. Coefcient (tCo)
In temp. coefficient adjustment, press “q“or “p“ to
change the temperature coefficient from 0.0 to 4.0.
Press “SET“ to confirm or press “SET“ more than 2
sec to return to P1.0 without confirming.
P2.1: Setting TDS factor(tds):
In P2.0, press “SET“ to enter P2.1. The factor will
flash on LCD. Press “q“or “p“ to change factor
from 0.40 to 1.00. Press “SET“ to confirm or press
“SET“ more than 2 seconds to return to P2. 0
without saving.
P3.1: Reset
After executing, all parameters will be reset to factor
default. The previous calibration information will be
cleared as well.
In P3.0, press “SET“ to enter P3.1. Press “p“to select
Y or N. Press “SET“ to confirm or press “SET“ more
than 2 seconds to return without confirming.
P4.1: Range 1 calibration info:
In P4.0, press “SET“ to enter P4.1 and review the
last calibration concentration. If the meter is not
yet calibrated, “---” will display on the LCD. The
calibration information will be override after
recalibration.
P4.2: Range 2 calibration info:
In P4.1, press “p“ to enter P4.2 and review the
last calibration concentration. If range 2 is not yet
calibrated, “---” will display on LCD. In P4.1 or P4.2,
press “SET“ to return to P4.0.

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Calibration Mode (CAL)
Selecting a calibration standard
For best results, select a conductivity or TDS standard
near the sample value you are measuring. Alternatively,
use a calibration solution value which is approximate 2/3
of the full scale of the measurement range you plan to
use. For example, in the 0 to 1999 uS range, use 1413 uS
solution for calibration.
DO NOT reuse the calibration solution. Contaminants in
the solution will affect the calibration and the accuracy
When to do the calibration?
Calibration is necessary and should be done regularly.
If measure the mid-ranges, calibrate the meter at least
once a month. Soak the probe for 15 mins before
calibration or measurement can saturate the probe
surface and minimize drift.
If measure the extreme temperatures or special
concentration (<100uS or >2mS), calibrate the meter at
least once a week to get specified accuracy
Conductivity calibration
1. Dip the probe into demineralized or distilled
water for about 30 minutes to rinse the probe.
2. Select the conductivity standard for calibration.
3. Pour enough solution into two separate clean
containers.
4. Power on the meter. Select the mode as
conductivity measurement mode.
5. Rinse the probe into one of above containers.
Gently stir the probe.

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6. Dip the rinsed probe into the second container.
Tap probe on the bottom of container to remove
air bubbles. Wait about 15 mins to make the probe
stabilize to the solution temperature.
7. Press “CAL“ more than 2 seconds to begin
calibration. The conductivity value of solution will
blink on LCD.
8. Press “p“ and “q“ to change the value in
order to match the value to the standard
solution(solution must be referred to
normalization temp. 20oC if P1.2 is adjusted as
20 oC). You can adjust the conductivity reading
for +30%. However, if the measured value and
standard value differs by more than 30%, it is
suggested to clean probe or replace meter.
9. When the “CAL” stop flashing, you can
press”SET“ less than 1 second to confirm and
return to conductivity measurement mode. If
“CAL” always blinks, check if the calibration
solution is stable enough and if the step 8 input
value is correct or not.
10. Repeat 1~9 for other ranges if needed.
11. To exit conductivity calibration mode without
confirming, press ”SET“ in step 9 more than 2
seconds.

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TDS Calibration
Option1: Using TDS standards
1. Insert the probe into demineralized or distilled
water for about 30 minutes to rinse the probe
2. Select the TDS standard for calibration. The
factory default setting of the TDS conversion
factor is 0.50. You can improve the calibration
accuracy by setting the TDS factor before starting
the calibration. Please refer Appendix A for more
information of TDS conversion factor.
3. Pour enough solution into two separate & clean
containers.
4. Turn on the meter. Press “MODE“ to select TDS
mode.
5. Rinse the probe into one of the containers. Gently
stir the probe.
6. Dip the rinsed probe into the second container.
Tap the probe on the bottom of container to
remove air bubbles. Let the probe stabilize to the
solution temperature.
7. Press “CAL“ more than 2 seconds to begin the
calibration. The TDS value will blink on the LCD.
8. Press the “q“ to adjust the value to match the
value to the standard solution.
9. When “CAL” stop flashing, press “SET“ to confirm
and return to TDS normal mode.
10. Repeat 1~9 for other ranges if needed.
Option2: Using Conversion Factors
TDS values are related to conductivity. You can calibrate
the meter by using conductivity standards as described
above and then program the meter with a given
conversion factor. Please refer to setting P2.1

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SPECIFICATION
Range : 0~1999uS/0~1999ppm
or 0~19.99mS/0~19.99ppt
Resolution : 1uS/ppm or 0.01mS/ppt
Accuracy : 1% Full Scale±1digit
TDS factor : 0.40~1.00
Calibration Standard : (0.2~1) * Full Scale
Range
ATC : 0~50°C
Temperature Accuracy : ±0.5°C
Temp. Coefcient : 0~4.0% per degree C
Normalization Temp. : 20 or 25°C
Operation temp. : 0~50°C
Power Requirements : 4pcs1.5V(Type: A76 or LR44)
- EMC: Conforms to EN61326-1.
This product complies with requirements of the
following European Community Directives: 89/ 336/
EEC (Electromagnetic Compatibility) and 73/ 23/ EEC
(Low Voltage) as amended by 93/ 68/ EEC (CE Marking).
However, electrical noise or intense electromagnetic
fields in the vicinity of the equipment may disturb the
measurement circuit. Measuring instruments will also
respond to unwanted signals that may be present within
the measurement circuit. Users should exercise care
and take appropriate precautions to avoid misleading
results when making measurements in the presence of
electronic interference.

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MAINTENANCE AND REPAIR
If there appears to be a malfunction during the
operation of the meter, the following steps should be
performed in order to isolate the cause of the problem.
1. Check the battery. Replace the battery
immediately when the “ ” symbol appears on the
LCD.
2. Review the operating instructions for possible
mistakes in operating procedure.
Except for the replacement of the battery, repair of the
meter should be performed only by a Factory Authorized
Service Center or by other qualified instrument service
personnel. The front panel and case can be cleaned with
a mild solution of detergent and water. Apply sparingly
with a soft cloth and allow to dry completely before
using. Do not use aromatic hydrocarbons or chlorinated
solvents for cleaning.
Make sure the electrode is clean! Between
measurements, rinse the electrode with deionised water.
If the eletrode has been exposed to a solvent immiscible
with water, clean it with a solvent miscible with water
e.g. ethanol or acetone and rinse carefully with water.
Store the electrode carefully! Before storing, rinse it
carefully in deionized water and store DRY.

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BATTERY REPLACEMENT
1. Turn off the meter and loose the battery cover in
counter-clockwise direction.
2. Replace the old batteries with four new LR44
button cells.
3. Put back the battery cover and turn it tightly. the
Red LED Low Battery indicator illuminates. The
batteries should be replaced as quickly as possible.

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TROUBLE SHOOTING
Power On But No Display
• Make sure you press power key more than 100 mS.
• Check the battery conditions and replace if
necessary
• Move batteries away for one minute and then
re-install.
Display Disappear
• Check whether the low battery icon is appeared
before the display is off. If yes, replace with new
batteries
Air Bubbles Adhere On Electrode
• Stir the electrode completely and better to dip
the electrode into solution at oblique angle. After
soaking the electrode for 15~30 minutes, inspect
the electrode carefully to make sure no bubbles
adhere.
• If air bubbles still exist, tap the bottom of the
container gently and stir the electrode to remove
the air bubbles. If above method are not working,
remove the electrode out of solution and blow at
the electrode to remove the air bubbles
Error Code
Parameter: Conductivity
“- - -“ Meter is in manual range 1 however the
measured value is higher than 1999uS.
• Press “p” more than 2 seconds to change
the range to range 2 or to auto ranging.

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“E03“ Conductivity value is over the range limit
(19.99mS) or meter is damaged.
• Put the meter in standard solution. If E03
still appears, send back for repair.
“E04“ Caused by temp. reading error
• Refer to error code of temp. After solving
the error of temp, E04 will disappear.
Parameter: TDS
“- - -“ Meter is in manual range 1 however the
measured value is higher than 1999*TDS factor
ppm
• Press “p” more than 2 seconds to change
the range to range 2 or to auto ranging.
“E04“ Caused by temp. or conductivity error
• Refer to error code of temp. After solving
the error of temp. & conductivity, E04 will
disappear.
Parameter: Temperature
“E01“ Temperature circuit is damaged
• Send back for repair
“E02“ Temp value is lower than range limit (0°C) or
temp. circuit is damaged
• Put the meter in room temp. for 5 mins. If
E02 still appears, send back for repair.
“E03“ Temp value is higher than range limit (50°C)
or temperature circuit is damaged
• Put the meter in room temp. for 5 mins. If
E02 still appears, send back for repair

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Appendix A:
Conductivity to TDS Conversion Factors
Conductivity
at 25 °C
TDS KCL TDS (NaCL) TDS (442)
ppm Factor ppm Factor ppm Factor
23μS 11.6 0.5043 10.7 0.4652 14.74 0.6409
84μS 40.38 0.4807 38.04 0.4529 50.5 0.6012
447μS 225.6 0.5047 215.5 0.4822 300 0.6712
1413μS 744.7 0.527 702.1 0.4969 1000 0.7078
1500μS 757.1 0.5047 737.1 0.4914 1050 0.7
2070μS 1045 0.5048 1041 0.5029 1500 0.7246
2764μS 1382 0.5 1414.8 0.5119 2062.7 0.7463
8974μS 5101 0.5685 4487 0.5 7608 0.8478
12,880μS 7447 0.5782 7230 0.5613 11,367 0.8825
15,000μS 8759 0.5839 8532 0.5688 13,455 0.897
80mS 52,168 0.6521 48,384 0.6048 79,688 0.9961
442: 40% sodium sulfate, 40% sodium bicarbonate and
20% sodium chloride
Appendix B: Calculating TDS Conversion Factors
The meter can be calibrated using TDS calibration
standard solutions. The calibration standard only needs
to give the TDS value at a standard temperature such as
25°C. To determine the Conductivity-to-TDS conversion
factor use the following formula:
Factor = Actual TDS ÷ Actual Conductivity @ 25°C
Denitions
Actual TDS: Value from the solution bottle label or as a
standard you make using high purity water and precisely
weighed salts.