TPS WP-81 User manual

Congratulations !
You have purchased the latest in Handheld Conductivity-TDS-Salinity-
pH-ORP-Temperature instrumentation. We trust that your new WP-81
will give you many years of reliable service.
The WP-81 is a breeze to operate. This manual has been designed to
help you get started, and also contains some handy application tips. If at
any stage you require assistance, please contact either your local TPS
representative or the TPS factory in Brisbane.
The manual is divided into the following sections:
1. Table of Contents
Each major section of the handbook is clearly listed. Sub-sections
have also been included to enable you to find the information you
need at a glance.
2. Introduction
The introduction has a diagram and explanation of the display and
controls of the WP-81. It also contains a full listing of all of the items
that you should have received with your WP-81. Please take the time
to read this section, as it explains some of items that are mentioned
in subsequent sections.
3. Main Section
The main section of the handbook provides complete details of the
WP-81, including operating modes, calibration, troubleshooting,
specifications, and warranty terms.
4. Appendices
Appendices containing background information and application notes
are provided at the back of this manual.
Model WP-81 Cond,
TDS, Sal, pH, ORP,
Temp. Meter
Version: 6.0
Date: 27-Jan-2014

Page 2
TPS Pty Ltd
ABN 30 009 773 371
Unit 6 / 253 Leitchs Road
Brendale, QLD,
Australia, 4500
Phone : [phone]
International : 61 7 32 058 027
Fax : [phone]
International : 61 7 3808 4871
Email : [email protected]
Web : www.tps.com.au

Page 3
Contents
1. Introduction.....................................................................................5
1.1 WP-81 Display and Controls.................................................................. 5
1.2 Unpacking Information........................................................................... 7
1.3 Specifications......................................................................................... 8
2. WP-81 Menu Structure..................................................................11
3. Operating Modes...........................................................................12
3.1 Selecting Conductivity, TDS (setting factor) or Salinity Mode .............12
3.2 Selecting pH or ORP (mV) Mode.........................................................12
4. Conductivity (TDS/Salinity) Calibration.......................................13
4.1 Calibration Procedure .......................................................................... 13
4.2 Calibration Notes ................................................................................. 15
4.3 Calibration Messages ..........................................................................15
5. pH Calibration................................................................................16
5.1 Calibration Procedure .......................................................................... 16
5.2 Calibration Notes ................................................................................. 17
5.3 Calibration Messages ..........................................................................18
6. mV/ORP Calibration......................................................................18
7. Temperature Calibration...............................................................19
7.1 Calibration Procedure .......................................................................... 19
7.2 Calibration Notes ................................................................................. 19
7.3 Calibration Messages ..........................................................................20
7.4 Manual Temperature Setting ............................................................... 20
8. Good Laboratory Practices (GLP)................................................21
8.1 To recall GLP information on the display............................................. 21
8.2 Failed Calibration.................................................................................22
8.3 Printing GLP Information to the RS232 Port........................................22
8.4 Instrument Serial Number....................................................................23
8.5 Additional GLP Features...................................................................... 23
9. Notepad Function..........................................................................24
9.1 Recording Readings into the Notepad.................................................24
9.2 Recalling Records from the Notepad...................................................24
9.3 Erasing Records from the Notepad .....................................................25
9.4 Printing Records from the Notepad to the RS232 Port........................ 25
10. Automatic Data logging.............................................................26
11. RS232 Port .................................................................................28
11.1 Setting the Baud Rate......................................................................28
11.2 Sending Readings to the RS232 Port.............................................. 28

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11.3 RS232 Configuration........................................................................28
11.4 Communication and Statistical Software .........................................28
11.5 Commands.......................................................................................29
11.6 Data Format .....................................................................................30
11.7 GLP Data Format.............................................................................31
12. Importing Data into Microsoft Excel ........................................ 32
13. Battery Saver Function............................................................. 34
14. Recharging the Battery............................................................. 35
15. Clock Function.......................................................................... 36
15.1 Setting the Clock..............................................................................36
15.2 Displaying or Hiding the Clock.........................................................36
16. Selecting k=0.1 or k=10 Conductivity Sensors ....................... 37
17. Selecting Buffers for Auto Buffer Recognition ....................... 38
18. Initialising the WP-81................................................................ 39
19. Instrument firmware version number. ..................................... 39
20. Troubleshooting........................................................................ 40
20.1 General Errors..................................................................................40
20.2 Conductivity Troubleshooting...........................................................41
20.3 pH and mV/ORP Troubleshooting ...................................................43
20.4 Temperature Troubleshooting..........................................................44
21. Appendices: pH and Conductivity Sensor Theory................. 45
21.1 Care, Cleaning and Maintenance of Conductivity Sensors .............45
21.2 Replatinising Conductivity Sensors..................................................46
21.3 pH Sensor Fundamentals ................................................................47
22. Warranty .................................................................................... 50

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1. Introduction
1.1 WP-81 Display and Controls

Page 6
Press to record readings into memory. See section 9.1.
Also used to select pH buffers for automatic buffer recognition at pH
calibration. See section 17.
Press to show or hide the date/time or temperature. See section 15.2.
Also used to select k=0.1 or k=10 sensor, when standard k=1 sensor
is not being used.
Press to start or stop automatic logging. See section 10.
Alternatively, press to transmit current reading plus date and time to
the RS232 port. See section 11.2.
Only used within the menu system on the WP-81.
Press to access the user-friendly menu system which makes the WP-
81 a breeze to operate.
and
The and keys are used for calibrating the temperature value
(section 7.1), setting the manual temperature compensation (section
7.4), setting the clock (section 15.1), setting the automatic logging
period (section 10), and displaying GLP information (section 8.1).
The key is also used to initialise the WP-81 at turn-on. See
section 18.

Switches the WP-81 on and off.
Display
32 character alpha-numeric display with user-friendly menu and
prompting system. Shows Conductivity/TDS/Salinity, pH/ORP and
Temperature simultaneously. Date and time can also be displayed.

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1.2 Unpacking Information
Before using your new WP-81, please check that the following
accessories have been included:
Part No
1. WP-81 Conductivity-TDS-Sal-pH-ORP-Temp instrument....... 121132/1
................................................................................................... 121132/3
................................................................................................... 121132/5
2. Conductivity/ATC/Temperature Sensor: k=1 1, 3 or 5m cable
(see cable label for part No) k=10 1, 3 or 5m cable
k=0.1 1, 3 or 5m cable
3. pH Sensor: (see cable label for part No) 1, 3 or 5m cable
4. Conductivity Standard, 200mL: 2.76 mS/cm ............... 122306
or 58.0 mS/cm ............... 122315
or 150.0 uS/cm ............... 122320
5. pH7.00 Buffer, 200mL............................................................ 121387
6. pH4.01 Buffer, 200mL............................................................ 121381
7. Battery charger...................................................................... 130037
8. Manual
Options that may have been ordered with your WP-81:
1. Extended cable...................................................................... 130040
2. RS232 Serial Interface Cable................................................. 130041
3. Communication software for Windows 95 and later ............... 130086
4. USB to Serial Adaptor (requires 130041 also) ....................... 130087
5. Hard Carry Case.................................................................... 130059
6. Battery charger lead for 12V cigarette lighter socket.............. 130046
7. Battery charger lead for 12V DC, with battery clips................ 130052
8. Solar Panel............................................................................ 130012

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1.3 Specifications
Conductivity
Ranges.............................4 ranges, with automatic range selection.
k=0.1 Sensor...0 uS/cm to 2000 uS/cm
k=1.0 Sensor...0 uS/cm to 20.00 mS/cm
k=10 Sensor...0 uS/cm to 200.0.mS/cm
Resolution.........................0.05% of selected range
Accuracy...........................0.5% of full scale of selected range at 25 OC
TDS
Factor:..............................0.40 to 1.00 - user set (factory default 0.65)
Ranges:............................4 ranges, with automatic range selection.
k=0.1 Sensor...0 ppM to 1000 ppM
k=1.0 Sensor...0 ppM to 10.00 ppK
k=10 Sensor...0 ppM to 100.0.ppK
Resolution.........................0.1% of selected range
Accuracy...........................0.5% of full scale of selected range at 25 OC
Salinity..............................k=0.1 Sensor 0 % to 0.10 %
0 PSU to 1.0 PSU
k=1.0 Sensor...0 % to 1.19 %
0 PSU to 11.9 PSU
k=10 Sensor...0 % to 8.00 %
0 PSU to 80.0 PSU
Resolution.........................0.01% / 0.1 PSU
Accuracy...........................0.5% of full scale of selected range at 25 OC
pH
Range...............................0 to 14.00 pH
Resolution.........................0.01 pH
Accuracy...........................0.01 pH
mV/ORP
Range...............................0 to ±500.0 and 0 to ±1500 mV (auto-ranging)
Resolution.........................0.15 and 1 mV
Accuracy...........................±0.3 and ±1 mV
Temperature
Range...............................-10.0 to 120.0 oC (Sensor limit 60 oC)
Resolution.........................0.1 oC
Accuracy...........................0.2 oC

Page 9
General Specifications
Temperature Compensation:
Conductivity/TDS/Salinity..... Automatic -5 to 70 oC
pH (only –not for mV/ORP) .... Automatic 0 to 100 oC
Manual 0 to 100 oC
Calibration:
pH........................................ Auto Standard Recognition in pH4.01,
pH6.86, pH7.00, pH9.18 or pH10.01
pH Sensor Asymmetry Range -1.00 to +1.00 pH
pH Sensor Slope Range...... 85.0 to 105%
Input Impedance.................. >3 x 1012 
mV/ORP.............................. Sensor calibration not available.
Conductivity/TDS/Salinity..... Auto Standard Recognition 150uS/cm,
1413uS/cm, 2.76mS/cm, 12.88mS/cm,
58.0mS/cm
Cond Sensor Span Range... k=0.1 Sensor: k=0.075 to k=0.133
k=1.0 Sensor: k=0.75 to k=1.33
k=10 Sensor: k=7.5 to k=13.3
Temperature........................ Use a reference thermometer.
Temperature Sensor Offset . -10.0oC to +10.0oC
Memory.................................... 3600 readings including date and time.
Automatic Logging.................... User-set for one reading every 1 to 90
seconds, 1 to 90 minutes, or 1 to 24 hours.
RS232 Output .......................... 300, 1200, 9600 & 19200 baud.
8 bits, no parity, 1 stop bit, XON/XOFF
Protocol.
Clock........................................ Calendar clock displays date, month,
hours, minutes & seconds.
Year is recorded in memory and
transmitted to the RS232 port, but is not
displayed.

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Battery Saver............................On : Auto switch-off after 5 minutes
Off : Continuous use
Bar Graph display of battery charge level.
Value of battery voltage available for
troubleshooting.
Good Laboratory Practices .......Date, Time and Value of last
Conductivity, pH and Temperature
calibration are stored, and can be
recalled or sent to the RS232 port at any
time.
Power .......................................6V NiMH Rechargeable Battery for
approx 40 hours operation.
Dimensions...............................195 x 110 x 55 mm
Mass.........................................Instrument only : Approx 520g
Full Kit : Approx 2.5kg
Environment .............................Temperature : 0 to 45 oC
Humidity : 0 to 95 % R.H.

Page 11
2. WP-81 Menu Structure
A detailed breakdown of the menu system of the WP-81 is shown below.
This diagram provides a quick reference for the WP-81 menu functions.

F1:Cal

F1:Cond
F2:pH
F3:Temp

F2:Notepad

F1:Recall
F2:Erase
F3:Print
F4:Prog

F1:Min
F2:Sec
F3:Hr
:Set Period

F3:Mode

F1:Cond/TDS/Sal

F1:Cond
F2:TDS
F3:Sal

F1:%
F2:PSU
F3:pH
F4:mV

F4:Setup

F1:Batt

F1:OFF
(Battery Saver)
|
F2:ON
(Battery Saver)
F2:Clock
F3:GLP

F1:Recall
F3:Print
F4:Baud

F1:300
F2:1200
F3:9600
F4:19200

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3. Operating Modes
3.1 Selecting Conductivity, TDS (setting factor) or Salinity Mode
To select Conductivity, TDS or Salinity mode…
1. Select the Mode menu ( F3:Mode)…
F1:Cond/TDS/Sal
F3:pH F4:mV
2. Press to select Conductivity mode Menu.
F1:Cond. F2:TDS
F3:Sal.
3. Press to select Conductivity mode.
Press to select TDS mode.
You will now be asked to enter the TDS Factor.
0.65TDS factor
:Set F1:Save
Press to select Salinity mode menu.
Select units
F1:% F2:PSU
Press to select % units.
Press to select PSU units.
Press to quit and retain the current selection.
3.2 Selecting pH or ORP (mV) Mode
To select pH or ORP/mV mode…
1. Select the Mode menu ( F3:Mode)…
F1:Cond/TDS/Sal
F3:pH F4:mV
2. Press to select pH mode.
Press to select ORP/mV mode.
Press to quit and retain the current selection.

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4. Conductivity (TDS/Salinity) Calibration
To achieve accurate Conductivity/TDS/Salinity results, the WP-81
requires calibration to a known Conductivity standard. The TDS and
Salinity values are derived from the Conductivity reading and do not
require a separate calibration. The conductivity of a solution varies with
temperature. The WP-81 uses Automatic Temperature Compensation
(ATC) referenced to the fixed temperature of 25oC.
A “” in place of the decimal point indicates that the
Conductivity/TDS/Salinity readout is not calibrated, or a past calibration
has failed. The “” will be removed once a Conductivity calibration has
been successfully performed in Conductivity standard.
4.1 Calibration Procedure
1. Plug the Conductivity sensor into the Conductivity socket.
If a k=0.1 or k=10 sensor is being used, ensure that the WP-81 is set
to the correct k factor before using the instrument (see section 16).
2. Switch the meter on.
3. Rinse the Conductivity sensor in distilled water. Shake off as much
water as possible. Blot the outside of the sensor dry. DO NOT BLOT
THE SENSOR WIRES.
4. Zero Calibration
Let the sensor dry in air.
Select Conductivity Calibration. ( F1:Cal. F1:Cond.)
5. When the reading has stabilised at or near zero, press the key to
calibrate.
A ““ will not be removed after a zero calibration.
6. Standard Calibration
Allowable Conductivity standards are 150uS/cm, 1413uS/cm,
2.76mS/cm, 12.88mS/cm and 58.0mS/cm, and should be selected
according to your range of interest.
If the WP-81 does not recognise the standard, it will display the
message, “NOT STD” during calibration. Calibration will fail if this
message is displayed.

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For plastic bodied k=1 and k=10 sensors, place the sensor into a
sample of Conductivity standard, so that it is immersed at least to the
vent hole in the white plastic cover. The white plastic cover MUST be
in place for correct readings.
For plastic bodied k=0.1 sensors, the white plastic cover MUST be
removed for correct readings.
For glass bodied sensors, immerse the sensor at least to the vent hole
in the glass body.
DO NOT place the sensor directly into the bottle of standard. Discard
the used sample of standard after use. It is advisable to use a narrow
sample vessel to minimise the use of standard solution.
7. Select Conductivity Calibration. ( F1:Cal. F1:Cond.)
8. When the reading has stabilised, press the key to calibrate.
The “”will now be replaced by a decimal point, if calibration was
successful.
9. The WP-81 is now calibrated for Conductivity and is ready for use in
this mode.

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4.2 Calibration Notes
1. A Zero calibration should be performed at least monthly. In low
conductivity applications (where a zero error is particularly significant)
a zero calibration may have to be done weekly.
2. A Standard calibration should be performed at least weekly. Of course,
more frequent calibration will result in greater confidence in results.
3. The WP-81 does not require re-calibration when alternating between
Conductivity, TDS and Salinity modes.
4. All calibration information is retained in memory when the WP-81 is
switched off, even when the battery is removed. This information can
be recalled or printed later using the GLP function (see section 8).
5. The WP-81 displays the value of the standard to which it will attempt to
calibrate. Ensure that the standard value displayed corresponds to the
standard that you are using.
6. If the WP-81 does not recognise the standard, it will display the
message, “NOT STD” during calibration. Calibration will fail if this
message is displayed.
4.3 Calibration Messages
1. If a Zero calibration has been successfully performed, the WP-81 will
display the following message, and the zero value of the sensor. For
example…
Calibrate OK
Zero= 0.00 uS
2. If a Standard calibration has been successfully performed, the WP-81
will display the following message, and the k factor of the sensor. For
example…
Calibrate OK
k= 1.00
3. If a Standard calibration has failed, the WP-81 will display the following
message, and the failed k factor of the sensor. For example..
Calibrate Fail
k= 1.50

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5. pH Calibration
5.1 Calibration Procedure
1. Plug the pH sensor into the pH socket. Temperature measurements
are made via the Conductivity sensor, so this needs to be connected
for Automatic Temperature Compensation.
2. Switch the meter on.
3. Ensure that temperature has been calibrated or manually set (see
sections 7.1 & 7.4). If the decimal point in the temperature reading is
shown by a ““, then the temperature value is not calibrated.
4. Remove the wetting cap from the pH sensor. Rinse the pH and
Conductivity sensors in distilled water and blot them dry.
5. Ensure that you are using buffers which have been selected for
automatic buffer recognition. See section 17 for a detailed
explanation.
6. Place both sensors into a small sample of pH7.00 (or pH6.86) buffer,
so that the bulb and reference junction are both covered, as per the
diagram below. DO NOT place the sensors directly into the buffer
bottle.

Page 17
7. Select pH Calibration. ( F1:Cal. F2:pH)
8. When the reading has stabilised, press the key to calibrate. If a 1
point calibration has been performed, the “”will not be removed until
a full 2 point calibration has been performed.
9. Rinse the pH and Conductivity sensors in distilled water and blot them
dry.
10. Place both sensors into a small sample of pH4.01, pH9.18 or pH10.01
Buffer, so that the bulb and reference junction are both covered, as
per the diagram in step 6, above. DO NOT place the sensors directly
into the buffer bottle.
pH9.18 and pH10.01 buffers are unstable once the bottles have
been opened. Discard immediately after use.
11. Select pH Calibration. ( F1:Cal. F2:pH)
12. When the reading has stabilised, press the key to calibrate. The
“”will now be replaced by a decimal point, if calibration was
successful.
13. The WP-81 is calibrated for pH and is ready for taking pH
measurements. Discard the used samples of buffer.
5.2 Calibration Notes
1. A 1-point calibration should be performed at least weekly. In
applications where the sensor junction can become blocked, such as
dairy products, mining slurries etc., a 1-point calibration may have to
be done daily.
2. A full 2-point calibration should be performed at least monthly. Of
course, more frequent calibration will result in greater confidence in
results.
3. All calibration information is retained in memory when the WP-81 is
switched off, even when the battery is removed. This information can
be recalled or printed later using the GLP function (see section 8).
4. The WP-81 displays the value of the pH buffer to which it will attempt
to calibrate. Ensure that the buffer value displayed corresponds to the
buffer that you are using.

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5.3 Calibration Messages
1. If a 1-point calibration has been successfully performed, the WP-81 will
display the following message, and the asymmetry of the sensor. For
example…
1 Point Cal. OK
Asy= 0.10pH
2. If a 1-point calibration has failed, the WP-81 will display the following
message, and the failed asymmetry value of the sensor. For
example…
1 Point Cal. Fail
Asy= 1.50pH Hi
or :
1 Point Cal. Fail
Asy= -1.50pH Lo
3. If a 2-point calibration has been successfully performed, the WP-81 will
display the following message, and the asymmetry and slope of the
sensor. For example…
2 Point Cal. OK
Asy= 0.10pH
then :
2 Point Cal. OK
Slope=100.0%
4. If a 2-point calibration has failed, the WP-81 will display the following
message, and the failed slope value of the sensor. For example…
2 Point Cal. Fail
Slope=130.0% Hi
or :
2 Point Cal. Fail
Slope= 70.0% Lo
6. mV/ORP Calibration
The mV section is factory calibrated. There is no user-calibration facility
for this mode.

Page 19
7. Temperature Calibration
7.1 Calibration Procedure
1. Plug the Conductivity/Temperature sensor into the Conductivity
socket. A separate temperature sensor can also be used in place of
the Conductivity sensor for temperature value.
2. Switch the meter on.
3. Place the sensor into a beaker of room temperature water, alongside
a good quality mercury thermometer. Stir the sensor and the
thermometer gently to ensure an even temperature throughout the
beaker.
4. Select Temperature Calibration. ( F1:Cal. F3:Temp )
5. The reading from the sensor is now displayed on the right of the
display, and the value you are going to set is shown on the left. For
example…
25.020*0oc
:Set F1:Cal.
6. When the reading on the right has stabilised, press the and
keys until the reading on the left shows the same temperature as the
mercury thermometer.
7. Press the key to calibrate the temperature value.
The “”will now be replaced by a decimal point, if calibration was
successful.
Alternatively, press the key to abort temperature calibration.
7.2 Calibration Notes
1. Temperature calibration information is retained in memory when the
WP-81 is switched off, even when the battery is removed. This
information can be recalled or printed later using the GLP function (see
section 8).
2. Temperature does not need to be re-calibrated unless the sensor is
replaced or the meter is initialised.

Page 20
7.3 Calibration Messages
1. If a temperature calibration has been successfully performed, the
WP-81 will display the following message and the offset value of the
sensor. For example…
Calibrate OK
Offset= 1.0oc
2. If a temperature calibration has failed, the WP-81 will display the
following message, and the failed offset value of the sensor.
Calibrate Fail
Offset= 10.5oc
7.4 Manual Temperature Setting
If the Conductivity/Temperature sensor is not connected, and a
temperature sensor is not used in its place, the temperature of the sample
solution must be set manually for accurate pH measurements. A separate
thermometer will be required for this.
NOTE: The Conductivity sensor has a separate sensor built in for
automatic temperature compensation for Conductivity, TDS and
Salinity.
1. Switch the meter on.
2. Measure the temperature of the sample.
3. Select Temperature Calibration. ( F1:Cal. F3:Temp)
4. The current temperature setting is now displayed.
25.0Man Temp
:Set F1:Save
5. Press the and keys until the display shows the temperature of
the sample.
6. Press the key to save the temperature value.
Alternatively, press the key to quit and retain the current setting.