TPS Aqua-pH User manual

Congratulations !
You have purchased the latest in Handheld, Waterproof pH-mV-
Temperature instrumentation. We trust that your new Aqua-pH will give
you many years of reliable service.
The Aqua-pH 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 Aqua-pH. It also contains a full listing of all of the
items that you should have received with your Aqua-pH. 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
Aqua-pH, 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.
TPS Pty Ltd
4 Jamberoo Street
Springwood, Brisbane,
Australia, 4127
Phone : [phone]
International : 61 7 32 900 400
Fax : [phone]
International : 61 7 3808 4871
Email : [email protected]
Web : www.tps.com.au
Model Aqua-pH
pH-mV-Temp. Meter
Version : 1.0
Date : 19/02/2002
Author : MS

Page 1
Contents
1. Introduction..............................................................................................2
1.1 Aqua-pH Display and Controls........................................................................... 2
1.2 Unpacking Information ...................................................................................... 4
1.3 Specifications.................................................................................................... 5
2. Operating Modes......................................................................................6
3. pH Calibration .......................................................................................... 7
3.1 Calibration........................................................................................................ 7
3.2 pH Calibration Notes......................................................................................... 9
3.3 pH Calibration Messages................................................................................. 10
4. Millivolt Calibration................................................................................ 11
5. Temperature Calibration........................................................................ 12
5.1 Calibration...................................................................................................... 12
5.2 Calibration Notes ............................................................................................ 13
5.3 Calibration Messages...................................................................................... 13
5.4 Manual Temperature Setting ........................................................................... 13
6. Selecting Buffers for Auto Buffer Recognition..................................... 14
7. Battery Saver Function.......................................................................... 15
8. Initialising the Aqua-pH ......................................................................... 16
9. Troubleshooting..................................................................................... 17
9.1 General Error Messages ................................................................................. 17
9.2 pH and mV Troubleshooting............................................................................ 18
9.3 Temperature Troubleshooting.......................................................................... 19
10. Appendices......................................................................................... 20
10.1 pH Sensor Fundamentals............................................................................ 20
10.2 Checking the reference junction of a pH sensor. .......................................... 23
10.3 Determining if an instrument or sensor is faulty............................................ 23
10.4 Instrument software version number............................................................ 24
11. Warranty ............................................................................................. 25

Page 2
1. Introduction
1.1 Aqua-pH Display and Controls

Page 3
¬Display
24 character alpha-numeric display. Can show any of the following
combinations readouts simultaneously (see section 2).
pH + Temperature Millivolts + Temperature Temperature only
A unique “Large Digit” mode nearly doubles the size of the digits
(section 2).
User-friendly prompts and error messages are also provided.
-Used to calibrate all parameters. See sections 3and 5.
Also used to select buffers for automatic buffer recognition. See
section 6.
®Used to select pH, mV or Temperature modes. See section 2.
¯Switches the Aqua-pH on and off.
Hold this key for 3 seconds to invoke Battery Saver mode. See
section 7.
°and ±
These keys toggle the Aqua-pH between Large Display mode and
Dual Display mode. See section 2.
NOTE: The digits in Large Display mode are made by combining the
two rows of the display. This results in a small gap
approximately half way up the digits.

Page 4
1.2 Unpacking Information
Before using your new Aqua-pH, please check that the following
accessories have been included:
Part No
1. Aqua-pH pH-mV-Temperature Instrument ..............................121112
2. pH Sensor, Porous Teflon Double Junction, 1m ......................121207
3. Temperature Sensor, Stainless Steel , 1m...............................121247
4. pH6.88 Buffer, 200mL..............................................................121306
5. pH4.00 Buffer, 200mL..............................................................121381
6. 9V Battery................................................................................130026
7. Aqua-pH Handbook................................................................ 130050
Options that may have been ordered with your Aqua-pH:
1. Hard Plastic Carry Case.......................................................... 130057

Page 5
1.3 Specifications
Ranges Resolution Accuracy
pH 0 to 14.00 pH 0.01 pH ±0.01 pH
mV 0 to ±1500 mV 1 mV ±1 mV
Temperature -10.0 to 120.0 OC0.1 OC±0.2 OC
Additional pH Specifications
Temperature Compensation...............Automatic, 0 to 50.0 OC
pH Input Impedance...........................>3 x 1012 Ω
pH Asymmetry Range........................-1.00 to 1.00 pH
pH Slope Range.................................85.0 to 105.0%
Auto pH Buffer Recognition................pH4.00, pH6.88, pH7.00 pH9.23,
pH10.06
Additional Temperature Specifications
Temperature Sensor Offset Range ....-10.0oC to +10.0oC
General Specifications
Display...............................................24 Character alphanumeric LCD,
with full text prompts and error
messages.
Power.................................................9V Alkaline Battery for 100+ hours
operation.
Battery Saver.....................................On :Auto switch-off after 5
minutes
Off : Continuous use
Dimensions........................................157 x 78 x 35 mm
Mass..................................................Instrument only :Approx 200g
Full Kit :Approx 1.5kg
Environment.......................................Temperature :0 to 45 OC
Humidity :0 to 90 % R.H.

Page 6
2. Operating Modes
Press the key to select the desired operating mode. The sequence is
shown in the following table…
pH Mode 7.00pH
25.0oc
pH data is shown on the top line and Temperature data is shown on the
bottom line.
The Temperature reading is shown with an “M” if the Temperature sensor is
unplugged and manual Temperature compensation is being used.
Select this mode to calibrate pH.
Press or to toggle between dual readout or large digit readout.
↓↓
mV Mode 1000mV
25.0oc
mV data is shown on the top line and Temperature data is shown on the
bottom line.
No Temperature data is shown if the Temperature sensor is unplugged, as
manual Temperature compensation is not applicable to mV.
Calibration is not available in this mode.
Press or to toggle between dual readout or large digit readout.
↓↓
Temperature Mode 25.0oc
Temperature data only is shown on the top line.
Select this mode to calibrate Temperature.
Press or to toggle between regular readout or large digit readout.
↓↓
Back to pH mode
Note: The decimal point is replaced by a ” ∗∗ “ if a pH or Temperature calibration
has failed (see sections 3and 5), if the unit is initialised (see section 8),
or if the unit has lost its factory calibration (see section 9.1).

Page 7
3. pH Calibration
A “ ∗” in place of the decimal point indicates that the pH readout is not
calibrated, or a past calibration has failed. The “ ∗” will be removed once
a full two-point pH calibration has been successfully performed.
3.1 Calibration
1. Switch the Aqua-pH on.
2. Select pH Mode (see section 2).
3. Plug the pH sensor into the BNC socket (this is the metal socket). For
automatic temperature compensation, plug the Temperature sensor
into the Temperature socket (this is the 6-pin plastic socket). If the
Temperature sensor is not connected, then the Aqua-pH will use
manual temperature compensation.
4. Ensure that temperature has already been calibrated, or manually set
(see sections 5.1 and 5.4). NOTE: If the decimal point in the
temperature reading is replaced by a “ ∗“, then the temperature
readout is not calibrated.
5. Remove the wetting cap from the pH sensor.
6. Rinse the pH and Temperature sensors in distilled water and blot
them dry.
7. Ensure that you are using the buffers which have been selected for
automatic buffer recognition. See section 6for a detailed explanation.
8. Place both sensors into a small sample of pH6.88 (or pH7.00) buffer,
so that the bulb and reference junction are both covered. See the
diagram over the page.

Page 8
DO NOT place the sensors directly into the buffer bottle. Discard the
used buffer after use.
9. When the reading has stabilised, press and hold the key for 2
seconds to calibrate. If a 1 point calibration has been performed, a “∗“
will not be removed until a full 2 point calibration has been performed.
10. Rinse the pH and Temperature sensors in distilled water and blot
them dry.
11. Place both sensors into a small sample of pH4.00, pH9.23 or
pH10.00 Buffer, so that the bulb and reference junction are both
covered, as per the diagram in step 8. DO NOT place the sensors
directly into the buffer bottle. Discard the used buffer after use.
pH9.23 and pH10.00 buffers are highly unstable. Avoid using
these buffers if possible. Discard immediately after use.
12. When the reading has stabilised, press and hold the key for 2
seconds to calibrate. The “ ∗“ will now be replaced by a decimal
point, if calibration was successful.
13. The Aqua-pH is calibrated for pH and is ready for use in this mode.

Page 9
3.2 pH 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 Aqua-pH is
switched off, even when the battery is removed.
4. The Aqua-pH displays the value of the pH buffer that it has
attempted to recognise at calibration. Ensure that the buffer value
displayed corresponds to the buffer that you are using.

Page 10
3.3 pH Calibration Messages
1. If a 1-point calibration has been successfully performed, the
Aqua-pH will display the following message, and then display the
asymmetry and slope of the sensor. If the meter has not been
calibrated at two points at this stage, the slope is set to 100.0%.
1 point 6.88
Cal. OK then: Asym= 0.10pH Slope=100.0%
2. If a 1-point calibration has failed, the Aqua-pH will display the
following message, then the failed asymmetry value of the sensor.
1 point 6.88
Cal. Failed then: Asym= 1.50pH
3. If a 2-point calibration has been successfully performed, the
Aqua-pH will display the following message, and then the asymmetry
and slope of the sensor.
2 point 4.00
Cal. OK then: Asym= 0.10pH Slope= 99.5%
4. If a 2-point calibration has failed, the Aqua-pH will display the
following message, and then the failed slope value of the sensor.
2 point 4.00
Cal. Failed then: Slope= 70.0%

Page 11
4. Millivolt Calibration
The mV section is factory calibrated. There is no user-calibration facility
for this mode.

Page 12
5. Temperature Calibration
A “ ∗” in place of the decimal point indicates that the Temperature
readout is not calibrated, or a past calibration has failed. The “ ∗” will be
removed once Temperature has been successfully calibrated.
5.1 Calibration
1. Switch the Aqua-pH on.
2. Select Temperature mode (see section 2).
3. Plug the Temperature sensor into the Temperature socket (this is the
6-pin plastic socket). If the Temperature sensor is not connected,
then the Aqua-pH will use manual temperature compensation. In this
case, refer to section 5.4 for details on setting manual temperature
compensation values.
4. 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.
5. When the reading has stabilised, press and hold the key for 2
seconds.
6. The reading from the sensor is now displayed on the top line, and the
value you are going to set is on the bottom line. For example…
Enter 25.0oc
Temp ↑↑ 26.0↓↓
7. Press the and keys until the bottom line shows the same
temperature as the mercury thermometer.
8. Press the key to calibrate the temperature readout.
Alternatively, press the key to abort temperature calibration.

Page 13
5.2 Calibration Notes
1. Temperature calibration information is stored in memory when the
meter is switched off, even if the battery is removed.
2. Temperature does not need to be re-calibrated unless the
Temperature sensor is replaced or the meter is initialised.
5.3 Calibration Messages
1. If a temperature calibration has been successfully performed, the
Aqua-pH will display the offset value of the sensor. For example…
Cal. OK
Offset=1.0oc
2. If a temperature calibration has failed, the Aqua-pH will display the
failed offset value of the sensor.
Cal. Failed
Offset=10.5oc
5.4 Manual Temperature Setting
1. Switch the Aqua-pH on.
2. Select Temperature mode (see section 2).
3. Manual temperature setting is only available if the Temperature
sensor is not connected.
4. Press and hold the key for 2 seconds. The current Manual
Temperature Setting is now displayed, for example…
Enter Man.
Temp ↑↑ 25.0↓↓
5. Press the and keys until the bottom line shows the
temperature which you wish to set. This value should be the same as
the temperature of the solution you are measuring.
6. Press the key to set the temperature.

Page 14
6. Selecting Buffers for Auto Buffer Recognition
The Aqua-pH is factory set to automatically recognise pH4.00, pH6.88
and pH9.23 buffers. However, some users may prefer to use pH7.00
instead of pH6.88 and pH10.00 instead of pH9.23. The following
procedure describes how to set which of these buffers are automatically
recognised at calibration.
1. Switch the meter OFF.
2. Press and HOLD the key while switching the meter back on.
3. Release the key when the message, “Buffer 1 Select” is
displayed.
4. The display will now show the currently selected primary buffer, for
example…
6.88pH
↑↑↓↓Select or
↔7.00pH
↑↑↓↓Select
5. Use the or keys to alternate between pH6.88 and pH7.00
buffers.
6. Press the key to save the primary buffer.
7. After the message, “Buffer 2 Select”, the display will now show the
currently selected secondary pH buffers, for example…
4.00/9.23pH
↑↑↓↓Select or
↔4.00/10.0pH
↑↑↓↓Select
8. Use the or keys to alternate between pH9.23 and pH10.00
buffers (the display shows pH10.0 for the latter but this buffer is
stored as pH10.00).
9. Press the key to save the secondary pH buffers.
10. The buffer recognition setting is kept in memory when the meter is
switched off, even if the battery is removed. The buffers are re-set to
pH6.88 and pH9.23 during initialisation.
NOTE: pH6.88 buffer is a DIN 19266 and NBS Primary-standard pH
solution, and is far more stable than pH7.00 buffer. If pH7.00
buffer is used, ensure that it is made to 0.01pH accuracy.

Page 15
7. Battery Saver Function
The Aqua-pH is equipped with a battery saver function. If no button has
been pressed for five minutes, the unit beeps and flashes the display for
20 seconds, and then shuts off. This function can be disabled for
continuous use.
To enable or disable the battery saver function:
1. Switch the Aqua-pH on.
2. With the meter already switched on, press and HOLD the key for
3 seconds.
3. The battery saver menu is now displayed. For example…
:ON ↑↑↓↓
9.00V
4. In this mode, use the or keys to toggle the battery saver
function on or off.
ON enables the battery saver function. The unit will turn itself off
after 5 minutes.
OFF disables the battery saver function. The unit will not switch itself
off.
NOTE: The display also shows the battery volts. This gives the
operator an idea of how much battery life is remaining. The
symbol flashes when the battery volts drops below 7.50
volts. At 6.00 volts the meter turns itself off.
5. When you have set the battery saver function to the desired position,
press the key to return to normal measurement mode.

Page 16
8. Initialising the Aqua-pH
If the calibration settings of the Aqua-pH exceed the allowable limits, and
the unit cannot be re-calibrated, then it may need to be initialised to
factory default values. This action may be required if a sensor is replaced.
To initialise the Aqua-pH…
1. Switch the Aqua-pH off.
2. Press AND HOLD the key while switching the Aqua-pH on.
3. The following messages are now displayed…
Memory & Cal
Reset !
↓↓
You MUST
Re-Calibrate
↓↓
TPS AQUA-P
V1.0 S1234
4. The meter then displays pH and Temperature. Note that the decimal
points have been replaced with a “ ∗“, to indicate that the unit
requires re-calibration.

Page 17
9. Troubleshooting
9.1 General Error Messages
Error
Message Possible Causes Remedy
Factory
Cal. Fail
See
Handbook
The EEPROM chip which
contains the factory
calibration information has
failed.
The unit must be returned to
TPS for service.
Memory
Failed
Calib.
Lost
Memory
Reset !
You MUST
Re-Cal.
User calibration settings
have been lost or corrupted. Re-calibrate the instrument.
A 2 point calibration is
required for pH (section 3)
and a 1 point calibration for
temperature (section 5).
Meter displays the
word OFF, and
switches off.
Battery is below 6.00 volts. Replace the battery.
Meter will not turn
on. Battery is exhausted. Replace the battery.
Flashing
symbol. Battery is below 7.50 volts. Replace the battery soon.
Note that the unit will switch
itself off when the battery
falls below 6.00 volts.

Page 18
9.2 pH and mV Troubleshooting
Symptom Possible Causes Remedy
Unit fails to
calibrate, even
with new sensor.
Calibration settings outside
of allowable limits due to
previous failed calibration.
Initialise the unit. See
section 8.
1 Point calibration
fails (Asymmetry
is greater than +/-
1.00 pH).
1. Reference junction
blocked.
2. Reference electrolyte
contaminated.
Clean reference junction, as
per instructions supplied
with the sensor.
Flush with distilled water
and replace electrolyte.
2 Point calibration
fails (Slope is less
than 85.0%).
1. Incorrect primary buffer.
2. Glass bulb not clean.
3. Sensor is aged.
4. Connector is damp.
5. Buffers are inaccurate.
Ensure that you are using
the buffers which the
Aqua-pH has been set to
automatically recognise
(See section 6).
Clean glass bulb as per
instructions supplied with
the sensor.
Attempt rejuvenation, as per
instructions supplied with
the sensor. If not successful,
replace sensor.
Dry in a warm place.
Replace buffers.
Continued over the page…

Page 19
pH and mV Troubleshooting, continued...
Unstable
readings. 1. Reference junction
blocked.
2. Glass bulb not clean.
3. Bubble in glass bulb.
4. Faulty connection to
meter.
5. Reference junction not
immersed.
6. KCl crystals around
reference junction, inside
the electrolyte chamber.
Clean reference junction, as
per instructions supplied
with the sensor.
Clean glass bulb as per
instructions supplied with
the sensor.
Flick the sensor to remove
bubble.
Check connectors. Replace
if necessary.
Ensure that the bulb AND
the reference junction are
fully immersed.
Rinse electrolyte chamber
with warm distilled water
until dissolved. Replace
electrolyte.
Inaccurate
readings, even
when calibration
is successful.
Reference junction blocked. Clean reference junction, as
per instructions supplied
with the sensor.
Displays 7.00 for
all solutions. Electrical short in connector. 1. Check connector. Replace if necessary.
2. Replace sensor.
Displays 4-5 pH
for all solutions. Glass bulb or internal stem cracked. Replace sensor.
9.3 Temperature Troubleshooting
Symptom Possible Causes Remedy
Displays “OVRoC”
when sensor is
plugged in.
1. Faulty sensor.
2. Faulty instrument.
Fit new sensor, part number
121247.
Return instrument to factory
for repair.
Temperature
inaccurate and
cannot be
calibrated.
1. Faulty connector.
2. Faulty sensor.
3. Faulty instrument.
Check the connector and
replace if necessary.
Fit new sensor, part number
121247.
Return instrument to factory
for repair.