palintest MICRO 500 User manual

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INSTRUMENTS
_____________________________________________________________________________________
MICRO 500
pH METER
OPERATING INSTRUCTIONS
PT 140 MICRO 500 pH METER
(pH/mV/Temp Meter)
____ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
PALINTEST LTD, Palintest House, Team Valley, Gateshead, Tyne & Wear England NE11 0NS
Tel: [phone] Fax: [phone] E-Mail: [email protected]om
® INST.21

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TABLE OF CONTENTS
1 INTRODUCTION....................................................................... 3
1.1 Introducing the Micro 500 pH Meter .......................................... 3
2 GETTING STARTED................................................................. 4
2.1 Description of Keypad Functions............................................... 4
2.2 Description of LCD Annunciators............................................... 4
2.3 Inserting & Removing the Rubber Boot ..................................... 5
2.4 Inserting New Batteries ............................................................. 5
2.5 Battery Replacement................................................................. 6
2.6 Connecting the Electrode and Temperature Sensor.................. 6
2.7 Switching the Meter On ............................................................. 6
3 CALIBRATION.......................................................................... 7
3.1 pH Calibration............................................................................ 7
3.2 Temperature Calibration............................................................ 9
3.2.1 With Temperature Probe for Preselected Curve....................... 9
3.2.2 With Temperature Probe with Curve Selection........................ 10
3.2.3 Without Temperature Probe (no ATC) ................................... 11
3.3 Millivolt (mV) Calibration.......................................................... 12
4 MEASUREMENT .................................................................... 13
4.1 Taking Measurements............................................................. 13
4.2 Holding a Reading................................................................... 14
4.3 Releasing a Held Reading....................................................... 14
5 ELECTRODE CARE AND MAINTENANCE ............................ 14
6 TROUBLESHOOTING ............................................................ 15
7 SPECIFICATIONS .................................................................. 16
8 ACCESSORIES ...................................................................... 17
9 WARRANTY............................................................................ 17
APPENDIX (Electrodes and Electrode Care) ...................... 18

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1 INTRODUCTION
1.1 Introducing the Micro 500 Series
Thank you for purchasing the Palintest Micro 500 pH
meter. This microprocessor-based hand-held meter is
easy to use and has a large custom LCD (Liquid Crystal
Display) for clear and easy reading.
The Micro 500 pH meter allows pH, temperature (°C) and
millivolt measurement. Millivolt measurement (mV) can be
used for taking Redox or ORP (Oxidation or Reduction
Potential) readings with ORP electrodes.
This instruction manual is organised for quick reference
with step-by-step procedures that give you thorough
review of the various features and meter operations.
Included with your meter are a pH electrode, temperature
sensor, rubber boot, 4 x alkaline ‘AAA’ batteries, an
instruction manual and a warranty card. Please refer to the
section on ‘Accessories’ for more information on pH
buffers and other accessories.

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2 GETTING STARTED
2.1 Description of Keypad Functions
The Palintest Micro 500 pH meter has four keys on its
splash-proof keypad. These include ON/OFF, HOLD/
ENTER, CAL and MODE/INC keys.
ON/OFF: Powers the meter on and turns it off. Meter
directly enters measurement mode when you
switch it on.
MODE: Selects measurement mode for pH, mV and
temperature.
CAL: Allows calibration for pH, mV or Temperature, or to
abort calibration without confirming any set value.
INC: Allows you to increment values during calibration
mode.
HOLD: Freezes the measured reading for easy viewing.
ENTER: Confirms calibration value.
2.2 Description of LCD Annunciators
The meter has a large custom LCD that consists of 3½-
digit segments and operation annunciators for pH, mV or
°C (temperature). Other annunciators include ‘HO’ (when
the HOLD function is activated) and ‘LO’ (low battery
condition) :
HO pH
o
C
LO mV

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2.3 Inserting & Removing the Rubber Boot
1 To remove meter from rubber boot, push out from the
bottom edges of meter until it is completely out of boot.
Ensure that the cables of pH electrode or temperature
probe are not connected.
2 To insert meter into rubber boot, slide in from the top of
meter before pushing the bottom edges of meter down to
set it into position. Lift up the stand at the back of meter
for bench top applications if necessary :
2.4 Inserting New Batteries
The battery compartment is found at the back of instrument.
To open the battery compartment, push in the direction of
arrow and lift up the cover. Note the polarity of battery
before inserting into position. After replacement, place
cover back and press down until it locks tight :

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2.5 Battery Replacement
A ‘LO’ annunciator in the LCD alerts you when battery
power is running low. Replace batteries as soon as
possible after ‘LO’ symbol appears :
Caution: Power off the meter when changing battery.
2.6 Connecting the Electrode and Temperature Sensor
To connect electrode into meter, align the connector slots
with the posts of meter’s socket and rotate connector
clockwise until it locks. Do not force when connecting. To
remove, simply rotate the connector in anti-clockwise
direction until it unlocks, and slide the connector off the
socket.
Insert the mini phono jack of temperature sensor into the
socket on the meter. Unplug the phono jack when not in use
or to measure pH without any temperature compensation.
2.7 Switching the Meter On
1 Press ON/OFF key to power up your meter. All LCD
segments display momentarily as the meter performs a
self-diagnostic test, per shown in section 2.2. The LCD
then switches into pH measurement mode.
pH
7.00
LO

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2 Press MODE key to choose your desired mode of
measurement with its corresponding annunciator displays in
the LCD. For temperature mode, the measured reading can
be 25.0°C (factory default) or the last calibrated temperature
value if there is no temperature probe, or the current
measured value if a temperature probe is connected.
3 The LCD displays ‘Ur’ if the meter reading exceeds the
maximum or ‘Or’ if under minimum possible measurement
range (refer to section on Specifications) :
3 CALIBRATION
3.1 pH Calibration
The meter is capable of up to three-point calibration with
standard pH buffer values at pH 4.01, 7.00 and 10.01 to
ensure accuracy across the entire range of the meter. It
also allows offset adjustment in mV and Temperature
modes. All new calibration values will automatically
override existing data.
It is recommended that you perform at least two-point
calibration at room temperature using standard buffers,
starting with pH 7.00 followed by either pH 4.01 or 10.01.
For a one-point calibration, calibration should be performed
with a pH buffer value closest to expected sample value
being measured. Otherwise calibrating at pH 7.00 is
advisable.
Ensure that you use fresh pH buffer solutions during
calibration. Do not re-use buffer solutions as they may be
contaminated and affect the calibration and accuracy of
measurements. Palintest Buffer Packs provide single-use
buffer solutions from easy to use buffer tablets (see
Accessories Section).
ur Or

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Before use, remove the plastic protective cap of pH electrode
and condition the glass bulb by soaking it in tap water for 1 -
2 hours. This hydrates the glass bulb if electrode is too dry or
has not been used for a long period of time.
Always rinse the probes with tap water or rinse solution
before and after each calibration/sample measurement to
avoid cross-contamination. For details please refer to
section on Probe Care and Maintenance.
1 Take a sample tube containing the pH 7 solution. Power
on the meter, and the meter will automatically enter pH
measurement mode.
2 Dip both electrode and temperature sensor into the buffer
solution. Swirl gently and wait for reading to stabilise
(approx 30 seconds).
3 Press CAL key to enter calibration mode. A ‘CA’ displays
momentarily and the display shows the current uncalibrated
reading flashing while in the calibration mode :
Allow reading to stabilise. The meter automatically
recognises pH 4.01, 7.00 or 10.01 buffers. Press ENTER
key once to confirm calibration, the LCD displays ‘CO’
momentarily once calibration is confirmed. The meter exits
calibration mode and returns to measurement mode :
Alternatively you can press CAL key to abort or exit
calibration mode, without accepting new value while you
are in calibration mode.
ca 7.00
pH
co 7.00
pH

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For 2 or 3-point calibration, repeat with pH buffers 4.01
and /or 10.01 for best accuracy.
Important: This meter has automatic buffer recognition
which identifies the correct pH buffer values during
calibration. If buffers other than pH 4.01, 7.00 or 10.01 are
used, or the electrode has worn out, the LCD will flash
‘Er1’. For pH 7, the tolerance is ± 1.50 pH, while for both
pH 4 and pH 10 is ± 1.00 pH :
3.2 Temperature Calibration
3.2.1 With Temperature Probe For Preselected Curve
The temperature sensor included with your meter is
factory-calibrated. Over time, the temperature calibration
may drift and require recalibration. If you replace the probe
you should calibrate temperature probe prior to pH or mV
calibration.
1 Connect your temperature probe to the meter. Press MODE
key to enter Temperature mode until ‘°C’ annunciator appears
in the LCD.
2 Compare the displayed value to a NIST certified
thermometer or other thermometer known to be accurate.
For best accuracy, place probe and thermometer in a
constant temperature bath.
3 Press CAL key to enter temperature calibration mode. The
LCD shows ‘CA’ momentarily and the displayed reading
flashes :
Er1
ca
o
C
26.5

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5 Press INC key until the displays shows the correct
temperature. The INC key will scroll to the maximum
allowable value and then loop back to the minimum
allowable value adjustment (maximum adjustment is ± 5°C
from factory default).
6 Press ENTER key to confirm calibration. The LCD displays
‘CO’ momentarily, and the meter reverts to measurement
mode :
3.2.2 With Temperature Probe (with Curve Selection)
In the event the temperature probe has drifted too far from
its original characteristic due to age and use or if the probe
is being replaced, it may be a good idea to match the
probe to the best curve. There are 3 curves programmed
in the unit. To choose the curve, proceed as follows :-
1 Connect your temperature probe to the meter. Dip the
probe in a constant temperature bath or a liquid whose
temperature can be checked with a thermometer known to
be accurate. For best accuracy, place the probe and
thermometer in a constant temperature bath.
2 Make sure that the meter is in the pH measurement mode.
Press CAL key and the pH value flashes to indicate that
you are in the CAL mode.
3 Press MODE key. The display will show the temperature
of measured liquid.
4 Press MODE key. Each press will take you through one
curve. Choose the curve which gives you a reading closest
to the actual value (of the bath or thermometer).
co
o
C
25.0

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5 Press ENTER key and the curve selection is complete.
The unit will now display the temperature with respect to
the curve selected.
6 To match the value exactly with the standard value, press
CAL key to enter temperature calibration mode. The LCD
shows ‘CA’ momentarily and the displayed reading
flashes.
7 Press INC key to make fine adjustment until the displays
shows the correct temperature. The INC key will scroll to the
maximum allowable value and then loop back to the
minimum allowable value adjustment (maximum adjustment
is ± 5°C from factory default).
8 Press ENTER key to confirm calibration. The LCD displays
‘CO’ momentarily, and the meter reverts to measurement
mode.
.
3.2.3 Without Temperature Probe (no ATC)
If no temperature probe is used, the meter compensates for
pH response at 25°C (factory default) or at a temperature
value manually set by you as follows :-
1 Press MODE key to enter into Temperature mode until
‘
°C’
shows in the LCD.
2 Compare displayed value to a certified thermometer or
other thermometer known to be accurate.

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3 Press CAL key to enter temperature calibration mode. The
LCD shows ‘CA’ momentarily and the displayed reading
flashes. Note that this displayed value should either be
25.0°C or last set temperature value :
4 Press INC key until the displays shows the correct
temperature. The INC key will scroll to the maximum
allowable value and then loop back to the minimum
allowable value adjustment (maximum adjustment is ± 5°C
from factory default).
5 Press ENTER key to confirm calibration. The LCD displays
‘CO’ momentarily, and the meter reverts to measurement
mode :
3.3 Millivolt (mV) Calibration
mV calibration is performed for ORP or Redox measure-
ments, where you can adjust its mV value as a base value for
measurements.
1 Press MODE key to enter mV mode, the LCD displays ‘mV’.
2 Press CAL key. The LCD shows ‘CA’ momentarily, and
the displayed reading flashes :
ca
o
C
25.0
co
o
C
25.0
ca
mV
103.1

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3 Use the INC key to adjust the reading to your desired value.
The maximum adjustment you can make is ± 50 mV.
Pressing INC key continuously allows you to scroll to the
maximum allowable value and then loops back to the
minimum allowable value.
4 Press ENTER key to confirm calibration. The LCD displays
‘CO’ momentarily and the meter reverts to measurement
mode. and shows the current set value :
4 MEASUREMENT
4.1 Taking Measurements
1 Before measurement, rinse both pH electrode and temper-
ature sensor thoroughly with tap or distilled water to remove
any impurities stuck onto the electrode body.
2 Power on the meter. Press MODE key to select your
desired mode of operation (pH, mV or Temperature).
3 Dip both probes gently into the test sample and wait for
the reading to stabilise. Note reading.
co
mV
105

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4.2 Holding a Reading
To freeze or hold your reading, press HOLD key once.
The LCD displays ‘HO’ annunciator to indicate the HOLD
function is activated :
4.3 Releasing a Held Reading
Press HOLD key again to deactivate the HOLD function or
to release your frozen reading. The meter returns to
measurement mode, and the ‘HO’ annunciator disappears
from the LCD :
5 ELECTRODE CARE AND MAINTENANCE
For best results, always keep the pH electrode bulb wet.
Store the pH bulb with electrode storage solution. Electrode
storage solution is available as part of the Palintest Electrode
Care Pack (see Accessories Section). If electrode storage
solution is not available, use tap water or buffer solution.
NEVER use deionised water for storage.
Wash the probes thoroughly with tap or distilled water
after each use.
Because your pH electrode is susceptible to contamination
or dirt, clean it every 1 to 3 months depending on extent
and condition of use.
HO
pH
3.20
pH
3.20

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Clean the electrode in a mild detergent solution. Wipe the
probe with a soft tissue paper. Avoid touching the glass
membrane with your fingers. Wash thoroughly in tap water
and then in distilled water. Recalibrate the meter after
cleaning the electrode.
6 TROUBLESHOOTING
Problem Cause Solution
Power ON but no Display a) Batteries not in place.
a) Insert batteries.
b) Re-insert batteries in
correct polarity.
‘LO’ displays in the LCD
a) Low battery.
a) Replace batteries with
fresh ones.
Unstable Reading
a) Electrode not deep
enough in sample.
b) Dirty electrode.
c) Broken electrode.
a) Place electrode deeper in
sample.
b) Clean electrode and recali-
brate.
c) Replace electrode.
‘Er1’ Display
a) Buffer value out of
tolerance.
a) Use new buffer solution
and recalibrate.
Not able to Calibrate
a) Display freezes.
b) Faulty electrode.
a) Release reading by
pressing HOLD key.
b) Replace electrode.

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7 SPECIFICATIONS
Palintest Micro 500 pH Meter
pH Range 0.00 to 14.00 pH
Resolution 0.01 pH
Accuracy ± 0.01 pH
Slope Range 80 to 120%
No of Calibration Points 1 to 3 points (push-button)
Buffer Options pH 4.01, 7.00, 10.01
Temperature Range 0.0 to 100.0°C
Resolution 0.1°C
Accuracy ± 0.5°C
Temperature Compensation
Automatic or Manual
(from 0 to 100°C)
Millivolt Range -1000 to +1000 mV
Resolution 1 mV
Accuracy +/- 2 mV
Auto Buffer Recognition pH 4.01, 7.00, 10.01
Hold Function ‘HO’
Auto Shut Off After 15 minutes
Low Battery Indication ‘LO’
Error Message Display ’Er1’
Display Single Custom LCD
Operating Temperature 0 to 50°C
Power Requirements 4 x ‘AAA’ Alkaline Batteries
Battery Life > 100 hours
Meter Dimensions 14 x 7 x 3.5 cm
Meter Weight 200g

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8 ACCESSORIES
Accessories available :-
CODE DESCRIPTION
PT 105/5 Buffer Pack pH 4/7/10
PT 105/8 Buffer Pack pH 7
PT 110/1B
pH Electrode - BNC Connector
PT 140/4 Temperature Sensor
PT 110/3B
ORP Electrode - BNC Connector
PT 105/4
Electrode Care Pack (incl Electrode
Storage Solution)
PT 105/12
Soil pH Access Set
9 WARRANTY
The Palintest Micro 500 pH Meter is guaranteed for a period
of one year from date of purchase - its associated pH
electrode is guaranteed for a period of six months from date
of purchase. This guarantee excludes accidental damage,
or damage caused by unauthorised repair or misuse.
Should repair be necessary, please contact our Technical
Services Department quoting the serial number on the base
of the instrument. This guarantee does not affect your
statutory rights.
_________________________

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___________________________________________________________________________________
ELECTRODES and ELECTRODE CARE
CARE OF PALINTEST pH ELECTRODES AND ORP ELECTRODES
Palintest Electrodes are supplied with Palintest pH Meters and as
replacement items. Palintest Electrodes are also suitable for use with
other types of general purpose pH meters.
Modern combination pH electrodes are of precision construction and
comprise a glass electrode and reference electrode in a single unit.
The porous ‘liquid junction’ provides continuity between the electrode
and the test solution. Palintest Electrodes are normally of a sealed
liquid or gel type which do not require refilling.
The operation of the pH meter is entirely dependent on the status of
the pH electrode. For this reason it is important that the electrode is
properly looked after and carefully maintained. Attention to electrode
maintenance will ensure correct pH readings and long electrode life.
If the electrode is neglected increasingly inaccurate readings will be
obtained and a new electrode will soon be required.
pH electrodes, by their very nature, have a limited life span. It is
difficult to predict how often a pH electrode will need to be replaced
as this will depend on the nature and frequency of its use and on how
well it is maintained. Under normal conditions when testing water or
simple aqueous solutions, a typical electrode life of 6 - 12 months can
be expected. Where the electrode is being used with aggressive
solutions such as acids and alkalis, solutions containing particulate
matter or with solutions containing non-aqueous solvents, then a
shorter electrode life can be expected.
ORP Electrodes (oxidation-reduction potential or redox electrodes)
comprise a platinum electrode in combination with a reference cell.
Whilst the operation of ORP electrodes is somewhat different from pH
electrodes they require similar care and maintenance. These instructions
can therefore be applied generally for the maintenance of ORP
electrodes.

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Electrode Types
Different types of electrode are supplied with different Palintest
meters depending on the model. Electrodes may be of glass-bodied
or epoxy-bodied construction. Electrodes terminate in a BNC
connector. Older types have a screw type connector.
When ordering replacement electrodes it is important to specify the
model of pH meter, the type of electrode required and the type of
connection fitted.
Electrode Installation
1 Remove the protective bottle cap from the tip of the electrode and
retain for future use.
2 Remove any salt deposits which may have formed on the surface
of the electrode by thoroughly rinsing with deionised water.
3 Soak the electrode for one hour by dipping into Palintest
Electrode Storage Solution (PT 105/4/2). If this is not available
the electrode may be soaked in water to which a little potassium
chloride has been added. Do not soak the electrode in
deionised water.
4 Connect the electrode to the pH meter.
Electrode Calibration (Buffering)
All pH electrodes are inherently unstable over time and for this reason
it is essential to calibrate the electrode regularly against buffer
solutions of known pH value. The calibration procedure is described
in the instructions provided with the pH meter. The frequency of
calibration against pH buffers will depend on the nature of use and
the accuracy required. For most purposes it will be sufficient to
calibrate the meter daily. For highly accurate work it may be
necessary to calibrate the meter each time it is used.
Palintest Buffer tablets provide a simple means of making up buffer
solutions for electrode calibration. The use of these tablets is
described on a separate leaflet (INST.7).
ORP electrodes provide a stable output and do not ordinarily require
recalibration before or during use. Note however that passivation and
poisoning of the electrode surface can result in a change of reading.

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Electrode Storage
To ensure that the electrode gives a rapid response, the tip of the
electrode and the liquid junction must not be allowed to dry out. Care
should be exercised therefore when storing the electrode between use.
For short-term storage between measurements of up to one week,
keep the electrode dipped in Palintest Electrode Storage Solution. If
this solution is not available, use water containing a small amount of
potassium chloride. Do not leave the electrode standing in
deionised water.
For long-term storage of more than one week, replace the electrode
tip in the protective bottle cap, the bottle cap should contain Palintest
Electrode Storage Solution. When returning the electrode to use
prepare it as for a new electrode.
Cleaning the Electrode
If the electrode becomes dirty it can be cleaned by one of the
following procedures :-
General Cleaning - Soak the electrode in 0.1M hydrochloric acid for
one hour.
Inorganic Deposits - Soak the electrode in 0.1M EDTA tetrasodium
salt for 15 minutes.
Oil and Grease - Rinse the electrode in methylated spirits or alcohol
solution. In severe cases the liquid junction may become completely
clogged with grease. In such cases the electrode should be replaced.
Protein - Soak the electrode in a solution of 1% pepsin in 0.1M
hydrochloric acid for 15 minutes.
After performing any of the above cleaning procedures, thoroughly
rinse the electrode with deionised water. Stand the electrode in
Palintest Electrode Storage Solution for at least one hour before use.
Trouble-Shooting Guide
If the pH meter will not give a steady reading, or fails to give a reading
of the expected value, check that the meter is being operated in
accordance with the instructions supplied then investigate the
electrode status.