LaMotte pHPLUS DIRECT 2 User manual

Code 5-1936-01

PREFACE
This manual serves to explain the use of the pHPLUS DIRECT 2 meter.
This manual functions in two ways: first as a step by step guide to
operating the meter; second, as a handy reference guide.
This manual is written to cover as many anticipated applications of
the meter as possible. If there are questions about the use of this meter
contact the LaMotte Tech Service Department.
LaMotte Company will not accept any responsibility for damage or
malfunction to the meter caused by improper use of the instrument.
The information presented in this manual is subject to change without
notice as improvements are made, and does not represent a commitment
on the part of LaMotte Company.
*WARNING: Reagents marked with an * are considered to be potential
health hazards. To view or print a Safety Data Sheet (SDS) for these
reagents go to www.lamotte.com. Search for the four digit reagent code
number listed on the reagent label, in the contents list or in the test
procedures. Omit any letter that follows or precedes the four digit code
number. For example, if the code is 4450WT-H, search 4450. To obtain a
printed copy, contact LaMotte by email, phone or fax.
Emergency information for all LaMotte reagents is available from Chem-
Tel: (US, 1-800-255-3924) (International, call collect, 813-248-0585).
WARNING! This set contains chemicals that
may be harmful if misused. Read cautions on
individual containers carefully. Not to be used by
children except under adult supervision.

TABLE OF CONTENTS
1. INTRODUCTION 5
2. GETTING STARTED 6
2.1 Description of Keypad Functions 6
2.2 Description of LCD Annunciators 7
2.3 Inserting & Removing the Rubber Boot/Stand 7
2.4 Inserting New Batteries 8
2.5 Battery Replacement 8
2.6 Connecting the Probe and Temperature Sensor 9
2.7 Conditioning the pH Probe 9
2.8 Switching the Meter On 9
3. CALIBRATION 10
3.1 pH Calibration 10
3.1.1 pH Calibration Procedure 11
3.1.2 Changing the pH Buffer Group 12
3.1.3 Resetting User Calibrated Values 12
3.2 Ion Calibration 13
3.2.1 Ion Calibration Procedure 13
3.3 Temperature Calibration 15
3.3.1 With Temperature Probe 15
3.3.2 Without Temperature Probe (no ATC) 16
4. MEASUREMENT 17
4.1 Taking Measurements 17
4.2 Millivolt (mV) Reference Check 17
4.3 Holding a Reading 17
4.4 Releasing a Held Reading 18
5. ELECTRODE CARE AND MAINTENANCE 18
6. TROUBLESHOOTING 19
7. SPECIFICATIONS 20
8. REPLACEMENT PARTS AND ACCESSORIES 21
9. WARRANTY 22
10. REPAIRS 22

5
1. INTRODUCTION
The pHPLUS DIRECT 2 microprocessor-based handheld meter is
economical and easy to use. It has a large custom LCD (Liquid Crystal
Display) for clear and easy reading.
The meter measures pH, mV (ORP), temperature and allows direct ion
concentration measurement of various ions (mono and divalent). The mV
mode is also useful for diagnosing problems with ion selective electrodes
(ISE).
The meter includes 4 alkaline “AAA” batteries, a rubber boot/stand, and
instruction manual. Please refer to Section 8 Replacement Parts and
Accessories for information on additional accessories and calibration
solutions.

6
2. GETTING STARTED
2.1 Description of Keypad Functions
The pHPLUS DIRECT 2 has six keys on the splash-proof keypad: ON/
OFF, HOLD/ENTER, CAL, MODE, or .
ON/OFF Powers meter on and off. Meter starts up in the mode that
was last used.
CAL Allows calibration for Ion, pH, mV or Temperature, or to
abort calibration and return to measure without confirming
a value.
MODE Selects measurement mode for Ion, mV, pH and
Temperature.
HOLD Freezes the measured reading for easy viewing.
ENTER Confirms calibration value.
Increments values during calibration mode.
Decrements values during calibration mode.

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2.2 Description of LCD Annunciators
The large custom LCD consists of 3½-digit segments which uses
annunciators for pH, mV or oC (Temperature). No annunciator is shown
in Ion mode. Other annunciators include “HO” (when HOLD function is
activated) and “LO” (low battery condition).
2.3 Inserting & Removing the Rubber Boot/Stand
1. To remove the meter from the rubber boot, push out the bottom
edge of the meter until it is completely out of the boot. Ensure
that the probe cables are not connected. See Figure 1.
2. To insert the meter into the rubber boot, slide in the top of the
meter before pushing the bottom edge of the meter down to set it
into position. Lift up the stand at the back of the meter for bench
top applications. Figure 2.
Figure 1 Figure 2

8
2.4 Inserting New Batteries
The battery compartment is found at the back of the instrument. To open
the battery compartment, push the cover in the direction of the arrow
and lift up. Note the polarity of the batteries before inserting them into
position. After the batteries have been replaced, reposition the cover and
press down until it locks.
2.5 Battery Replacement
The “LO” annunciator on the LCD alerts when battery power is running
low.
Caution: Power offthe meter before changing battery.

9
2.6 Connecting the Probe and Temperature Sensor
To connect the probe to the meter, align the BNC connector slots with
the posts of the meter socket and rotate the connector clockwise until
it locks. Do not force the connector. To remove the probe, rotate the
connector in a counter-clockwise direction until it unlocks, and slide the
connector offthe socket.
Insert the mini phono jack of the temperature sensor into the socket on
the meter. Unplug the phono jack when not in use or when measuring pH
without temperature compensation.
2.7 Conditioning the pH Probe
For best results condition the pH probe before the first use, or if it has
not been used for a long time, by soaking it in pH 4 buffer solution for at
least 1 hour. Rinse before use.
2.8 Switching the Meter On
1. Press the ON/OFF key. All LCD segments will display
momentarily as the meter performs a self-diagnostic test. The
meter will display “- - -“ if the meter has not been calibrated or if
the meter has been reset.
2. Press the MODE key to choose the desired measurement mode.
If a temperature probe is not connected, either 25.0°C (factory
2.5 mm mini phono
jack for
temperature sensor
BNC connector
for pH/ORP probe
or Ion Selective
Electrode

10
default) or the last calibrated temperature value will be
displayed. If a temperature probe is connected, the current
measured temperature will be displayed.
3. “Or” (Over range) indicates the reading exceeds the maximum
measurement range.
“Ur” (Under range) indicates the reading is under the minimum
measurement range (see Section 7 Specifications).
3. CALIBRATION
3.1 pH Calibration
The meter is capable of calibrating up to 3 pH values using USA or NIST
(nSt) pH buffer standards or 2 pH values with Low Ionic (Pb) pH buffer
standard. All new calibration values will automatically override existing
data.
USA group 4.01, 7.00, 10.01
NIST group 4.01, 6.86, 9.18
Pb group 4.10, 6.97
For the best results perform at least a 2-point calibration at room
temperature (25 °C) using standard buffers. Begin with pH 7.00 (USA
group), pH 6.86 (NIST group) or pH 6.97 (Pb group).
For a 1-point calibration, the calibration should be performed with a pH
buffer value closest to the expected sample value being measured.
The meter has automatic buffer recognition that identifies the correct pH
buffer values during the calibration. The meter will accept calibration
values that are within +/-1.0 pH units of the expected value, otherwise
the DISPLAY will flash “Er1” and the value will not be accepted. Press
CAL to abort the calibration and return to the measurement mode.
Always use new pH buffer solutions for calibration. Do not reuse
buffer solutions that may be contaminated and affect the calibration
and accuracy of the measurements. Promptly seal containers and store
solutions in a dark, dry, cool environment.

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Before use, remove the plastic protective cap on the pH probe and
condition the glass bulb by soaking it in tap water or pH buffer
(preferably pH 4) for 1-2 hours. This will hydrate the glass bulb if the
probe is too dry or if it has not been used recently. Always rinse the
probe with clean water before and after each calibration or sample
measurement to avoid cross-contamination. For details refer to Section 5
on Probe Care and Maintenance.
3.1.1 pH Calibration Procedure
1. Turn on the meter and select pH by pressing MODE if necessary.
2. Press CAL to begin pH calibration mode. “CA” (calibrate) will
display briefly. Notice that the pH reading and “pH” annunciator
will both blink.
3. Pour a known pH buffer calibration standard solution, e.g. pH 7.00,
into a clean, dry container. Dip the pH probe and temperature
probe into the solution. Stir gently and wait for the reading to
stabilize (approximately 30 seconds depending on the probe
condition).
4. When the pH reading has stabilized, the pH annunciator will
stop blinking. Press HOLD/ENTER to confirm the value. “CO”
(confirm) will display briefly. The pH value is automatically
adjusted to the buffer value shown from your selected buffer group.
The example below shows a successful pH 7.00 calibration
at 25 °C.
5. For a one-point calibration with pH 7.00 or 6.86 only, press
CAL to return to measurement mode. However for the greatest
accuracy, perform a multiple-point calibration. Repeat steps 3
& 4 with additional pH buffer calibration standards. When you
have completed the preset number of calibration points, the
meter will automatically save the calibration, cease blinking,
and begin pH measurement.

12
3.1.2 Changing the pH Buffer Group
The meter can be calibrated with pH standards of USA, NIST (nSt) or
Low Ionic (Pb) pH buffer groups. The factory default is the USA buffer
group. To abort the buffer group selection, press CAL to revert to the pH
measurement mode.
1. Power offthe meter while in pH mode. Press and hold MODE
then press ON/OFF. If successful, “bUF” will blink on the
display. Release both keys.
2. Press HOLD/ENTER to enter the buffer group selection mode.
3. Press MODE to toggle between the available pH buffer groups.
4. Press HOLD/ENTER to confirm the pH buffer group. Note: if
Pb is selected, measurement mode will begin. If USA or nSt is
selected, proceed to step 5.
5. Press MODE to toggle between the desired number of calibration
points (Pt). Note: During pH calibration mode, the meter will
automatically complete calibration after the number of points
selected here has been completed.
6. Press HOLD/ENTER to confirm the number of calibration
points. The meter will automatically begin the measurement
mode.
Note: To abort the buffer group selection or go back one step,
press CAL.
45
23

13
3.1.3 Resetting User Calibrated Values
The calibrated pH/mV/Ion values can be reset to the factory default using
the procedure below. The temperature offset will not be reset using this
procedure. To abort the reset, press CAL to revert to the measurement
mode.
1. Press and hold CAL while switching the meter on using the ON/
OFF key. The DISPLAY will show “rSt” blinking.
2. Press the ENTER key to confirm. The meter will automatically
clear all stored pH/Ion calibrations or mV offset values and
revert to the measurement mode.
3.2 Ion Calibration
The meter is capable of a 2 or 3 point ion calibration with standard
solutions. The meter will display “- - -“ if the meter has not been
calibrated or if the meter has been reset.
To abort the ion calibration, press CAL to revert to the measurement
mode.
Ion calibration values are not stored in the meter’s non-volatile memory.
Ion calibration data is lost once the meter is reset and when the batteries
are removed and replaced.
The error message “Er2” will be displayed after a single point calibration
is completed. Recalibrate using a minimum of 2 points.
Calibration values are successfully stored if the ISE (Ion Selective
Electrode) slope is within the specified tolerance of 15-90mV/decade,
otherwise an error message “Er3” will be displayed.
If any of the calibration points are not within 1 decade of each other, an
error message “Er4” will be shown at the end of calibration process.
The ion calibration options available include 0.1, 1.0, 10.0, 100.0 ppm.
Recalibrate and ensure that consecutive calibration points are 1 decade
apart from each other.
Ensure that new or fresh standard solutions are used during the
calibration. Do not reuse ion standard solutions because they may be
contaminated and affect the calibration and accuracy of measurements.
Store standard solutions in a dry, cool environment. Check that electrodes
and ion standard solutions are kept in good condition for best results.
Before use, remove the plastic protective cap at the tip of sensor of
the electrode and refer to the electrode instruction manual for proper
operation. Rinse the electrode before and after each calibration or sample
measurement to avoid cross-contamination.

14
3.2.1 Ion Calibration Procedure
The pHPLUS Direct 2 can measure a variety of ions. Ion measurement
requires an ISE (Ion Selective Electrode)—(sold separately) which
measures the specific ion of interest—such as ammonia or fluoride.
The available ion calibration values 0.1, 1.0, 10.0, and 100.0 ppm.
Chose any 2 or 3 consecutive values and prepare the corresponding
ion calibration standards. Turn on the meter and select the ion mode by
pressing the MODE key. For the best results, always calibrate first with
the lowest standard value, followed by the next lowest standard.
1. Dip the electrode into the standard solution. Add ISA (Ion
Selective Adjustment solution) if required. Stir the solution
gently with the electrode. Press the CAL key to begin the
calibration mode.
2. The display will show “CA” (to indicate the calibration
mode) momentarily followed by “0.1” flashing. To select the
appropriate standard, use the or keys.
3. Press ENTER to confirm that the ppm value is the desired
standard. The displayed value will then show the corresponding
mV reading for the selected ppm value. Allow the reading to
stabilize.
4. When the mV reading is stable, press ENTER to complete the
calibration for the first standard. The display will show the next
highest calibration standard value. Rinse the electrode with clean
water.
5. Dip the electrode into the next highest standard solution. Add
ISA if required. Stir the solution gently with the electrode. Press
the CAL key to begin the calibration mode.

15
6. Press ENTER to confirm that the ppm value is the desired
standard. The displayed value will show the corresponding
mV reading for the selected ppm value. Allow the reading to
stabilize.
7. When the mV reading is stable, press ENTER to complete the
calibration for the second standard. The display will show the
next highest calibration standard value. Rinse the electrode with
clean water.
8. To calibrate a 3rd point, repeat steps 6 & 7. To exit from 2-point
calibration, press the CAL key.
9. The ISE slope in mV value “PXX mV” will momentarily be
displayed before reverting to the ion measurement mode.
If the calibration is not successfully stored in the memory, an error
message “Er3” will be displayed. This occurs when the slope is lower
than 15mV/decade or higher than 90mV/decade.
3.3 Temperature Calibration
3.3.1 With Temperature Probe
The temperature probe supplied with the meter is factory calibrated. Over
time, the temperature calibration may drift and require recalibration. If
the temperature probe is replaced the meter should be recalibrated.
1. Connect the temperature probe to the meter. Press the MODE
key until the “°C” annunciator appears on the DISPLAY.
2. Compare the displayed value to a NIST certified thermometer or
other thermometer known to be accurate. For the most accurate
results, place both the probe and thermometer in a constant
temperature bath.

16
3. Press the CAL key to enter the temperature calibration mode.
The DISPLAY will show “CA” momentarily and the displayed
reading will flash.
4. Press the or keys until the display shows the desired
temperature. The meter will allow an adjustable maximum value
of ± 5 °C from the factory default.
5. To cancel or abort this operation, press the CAL key. To confirm
the calibration, press the ENTER key. A new value will be
stored in the meter non-volatile memory. The meter will display
“CO” momentarily, and then revert to the measurement mode.
3.3.2 Without Temperature Probe (no ATC)
If a temperature probe is not used, the meter will compensate the pH
response based on a temperature value that has been manually set or at
the factory default of 25.0 °C.
1. Press the MODE key until “°C” shows on the DISPLAY.
2. Compare the displayed value to a NIST certified thermometer or
thermometer that is known to be accurate (dipped into a constant
temperature bath).
3. Press the CAL key to enter the temperature calibration mode.
The DISPLAY will show “CA” momentarily and the displayed
reading will flash. Note that the displayed value should be either
25.0 °C or the last set temperature value.
4. Press the or keys until the displays shows the desired
temperature. The value can be set from 0 to 100 °C.

17
5. To cancel or abort this operation, press the CAL key. To confirm
the calibration, press the ENTER key. A new value will be
stored in the meter non-volatile memory. The DISPLAY will
display “CO” momentarily, and the meter will revert to the
measurement mode.
4. MEASUREMENT
4.1 Taking Measurements
1. Before measurement, rinse the pH/ORP probe or Ion Selective
Electrode and temperature probe with clean water to remove any
impurities.
2. Power on the meter using the ON/OFF key. Press the MODE
key to select the desired mode of operation (pH, mV, Ion, or
Temperature).
3. Dip the probes in the aqueous test sample. Stir gently with the
probes and wait for the reading to stabilize. Note the reading.
Freeze the displayed if desired—for details refer to Section 4.3
Holding a Reading.
4. Rinse the probes with clean water before taking the next reading
or storing the meter.
4.2 Millivolt (mV) Reference Check
The mV mode can be used for the diagnosis of an ISE or pH probe
condition. Press MODE to access the mV mode. The “mV” annunciator
will be displayed. The displayed value will show the absolute mV value
of the ISE or pH probe being measured.
4.3 Holding a Reading
To freeze or hold the displayed reading, press the HOLD key once. The
DISPLAY will display the ”HO” annunciator to indicate the HOLD
function is activated.

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4.4 Releasing a Held Reading
Press the HOLD key once again to deactivate the HOLD function
or to release the frozen reading. The meter will revert to the current
measurement mode, and the “HO” annunciator will disappear from the
DISPLAY.
5. ELECTRODE CARE AND MAINTENANCE
For best results, store the ISE dry and the pH/ORP probe bulb wet.
Store the pH/ORP glass bulb in pH probe storage solution. NEVER use
deionized water for storage. Wash probes with clean water after each use.
ISEs and pH probes are susceptible to contamination and dirt. Clean
them as needed using mild detergent and warm water. Blot the probe
gently with soft tissue paper to dry. Avoid excessive rubbing of the
glass membrane and avoid touching it with the fingers. Recalibrate after
cleaning.

19
6. TROUBLESHOOTING
Problem Cause Solution
No display Batteries not in place. a) Insert batteries.
b) Re-insert batteries in
correct polarity.
“---“ on
display
Meter does not have 2
point calibration
Perform 2 or 3 point ion
calibration.
“LO” displays
in the
DISPLAY
Low battery Replace batteries.
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
recalibrate.
c) Replace electrode.
“Er1” display Buffer value out of
tolerance
Use fresh pH buffer
solution and recalibrate.
Ensure correct pH buffer
group was selected.
“Er2” display Single point calibration Perform at least 2 point
calibration.
“Er3” display ISE slope not within the
specified tolerance
Check ISE is in good
working condition-refer to
ISE section of manual.
“Er4” display Calibration points not
within 1 decade
Ensure calibration points
are within 1 decade of
each other.
Not able to
calibrate
a) Display freezes
b) Faulty electrode
c) Inaccurate buffer
a) Release reading by
pressing HOLD.
b) Replace electrode.
c) Replace expired buffer
solutions.

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7. SPECIFICATIONS
Ion Range 0.01 to 1999 ppm
Resolution 0.01 ppm for 0.01 to 0.99 ppm/0.1 ppm
for 1.0 to 199.9 ppm/1 ppm for 200 to
1999 ppm
Accuracy ±1% of reading
No. of Calibration Pts 2 to 3 points (minimum 2 pts)
pH Range 0.00 to 14.00 pH
Resolution 0.01 pH
Accuracy ±0.01 pH
pH Slope Range 80 to 120%
No. of Calibration Pts 1 to 3 points (push-button)
Buffer Options pH 4.01, 7.00, 10.01 (USA)
pH 4.01, 6.86, 9.18 (NIST)
pH 4.10, 6.97 (Pb)
Temperature Range 0.0 to 100.0 °C
Resolution 0.1 °C
Accuracy ±0.5 °C
Temperature Comp. Automatic / Manual (0 to 100 °C)
Millivolt Range -500 to 500 mV
Resolution 0.1 mV for –200 to 200 mV;
1 mV for 200 to 500 mV
Accuracy ±0.2 and 2 mV resp.
Features
Auto-Buffer Recognition Yes
Hold Function “HO”
Auto Shut OffAfter 17 minutes
Low Battery Indication “LO”
Display Single Custom DISPLAY
Operating Temperature 0 to 50 °C
Power Requirements 4 x “AAA” Alkaline Batteries
Battery Life 500 hours
Meter Dim./Weight 15.7 x 8.5 x 4.2 cm / 255 g