LaMotte pHPLUS DIRECT User manual

Instruction Manual
pHPLUS DIRECT
pH/mV/ISE Meter
Code 5-1936

PREFACE
This instruction manual serves to explain the use of the pHPLUS DIRECT
meter.
It functions in two ways: first as a step by step guide to help you operate the
meter; second, it serves as a handy reference guide.
This manual is written to cover as many anticipated applications of the
pHPLUS DIRECT meter as possible. If there are doubts in the use of this
meter, please do not hesitate to contact the LaMotte Tech Service
Department.
LaMotte 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.
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Table of Contents
1. Introduction ............................. 5
2. Getting Started ........................... 6
2.1 Description of Keypad Functions ................... 6
2.2 Description of LCD Annunciations ................. 7
2.3 Inserting & Removing the Rubber Boot ............... 7
2.4 Inserting New Batteries ........................ 8
2.5 Battery Replacement ......................... 8
2.6 Connecting the Electrode and Temperature Sensor .........8
2.7 Condition the pH Electrode ..................... 9
2.8 Switching the Meter On ....................... 9
3. Calibration ............................. 10
3.1 pH Calibration............................ 10
3.2 Selection of pH buffer standards .................. 11
3.2.1 Resetting the User Calibrated Values ............... 11
3.2.2 pH Calibration using USA standard buffers ...........12
3.2.3 pH Calibration using NIST standaard buffers ...........13
3.2.4 pH Calibration using Pb Standard buffers ............14
3.3 Ion Calibration ........................... 15
3.3.1 Multi-point Ion Calibration ................... 16
3.4 Temperature Calibration ...................... 17
3.4.1 With Temperature probe .................... 17
3.4.2 Without Temperature probe (no ATC) .............18
4. Measurement ............................ 19
4.1 Taking Measurements ........................ 19
4.2 Millivolt (mV) Reference Check .................. 19
4.3 Holding a Reading .......................... 19
4.4 Releasing a Held Reading ...................... 19
5. Electrode Care and Maintenance .................20
6. Troubleshooting .......................... 20
7. Specifications ........................... 21
8. Accessories ............................. 22
9. Warranty Information ..................... 22-23
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1. INTRODUCTION
Thank you for purchasing the pHPLUS DIRECT meter. This
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 pHPLUS DIRECT measures pH, mV (ORP), temperature and ion
concentration of various ions (mono and di valence) with ion selective
electrodes (ISEs).
Included with your meter are a robust rubber boot, 4 alkaline “AAA” batteries,
buffer solutions, accessories, temperature sensor, instruction manual and a
warranty card. To order other accessories and buffer calibration or standard
solutions, please refer to Section 8 on Accessories for more information.
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2. GETTING STARTED
2.1 Description of Keypad Functions
The pHPLUS DIRECT has six keys on its splash-proof keypad with tactile
feedback. The keys include ON/OFF,HOLD/ENTER,CAL,MODE,p
and qkeys.
Powers meter on and off. Meter starts up in the mode that you were in
before turning the meter off.
Selects measurement mode for Ion, mV, pH and Temperature.
Allows calibration for Ion, pH, mV or Temperature, or to abort
calibration without confirming any set value.
Allows you to increase values during calibration mode.
Allows you to decrease values during calibration mode.
Freezes the measured reading for easy viewing.
Confirms calibration value.
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CAL
MODE
ON
OFF
HOLD
ENTER
ON
OFF
CAL
HOLD
ENTER
HOLD
ENTER
MODE

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). Note that there is no
annunciator shown in the Ion mode. Other annunciators include “HO” (when
the HOLD function is activated) and “LO” (low battery condition).
2.3 Inserting & Removing the Rubber Boot
1. To remove the meter from the rubber boot, push out the bottom edges of
the meter until it is completely out of the boot. Ensure that the cables of
the ISE/pH electrode or temperature probe are not connected
2. To insert the meter into the rubber boot, slide the top of the meter into the
boot before pushing the bottom edge of the meter down to set it into
position. Lift up the stand on the back of the meter for bench top
applications if desired.
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2.4 Inserting New Batteries
The battery compartment is found at the back of the instrument. To open the
battery compartment, push in the direction of the arrow and lift up the cover.
Note the polarity of the batteries before inserting them into position. After
replacement, replace the cover and press down until it locks tight.
2.5 Battery Replacement
A“LO” annunciator in the LCD alerts you when battery power is running low.
Replace the batteries with the type recommended by the manufacturer.
Caution: Power off the meter when changing the batteries.
2.6 Connecting the Electrode and Temperature Sensor
To connect the electrode to the meter, align the connector slots with the posts
of the meter socket and rotate the connector clockwise until it locks. Do not
force it when connecting. To remove the electrode, simply rotate the
connector in a counterclockwise direction until it unlocks, and slide the
connector off the socket.
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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 pH is being measured
without any temperature compensation.
2.7 Condition the pH Electrode
Condition the pH electrode before the first use or if it has not been in use for a
long time by soaking it in a container filled with pH 4 buffer solution for at
least 1 hour. Rinse with tap water before proceeding.
2.8 Switching the Meter On
1. Press the ON/OFF key to power up the meter. All LCD segments will be
displayed momentarily as the meter performs a self-diagnostic test, as
shown in section 2.2. The meter will be in the Ion measurements mode if
the meter has not been calibrated or reset. The display will show "---".
2. Press the MODE key to choose the desired mode of measurement, The
corresponding annunciator will be displayed on the LCD. In the
temperature mode, the display will show 25°C (factory default), the last
calibrated temperature if there is no temperature probe connected, or the
current measurement value if a temperature probe is connected.
3. The display will show “Ur” if the measurement is under the minimum
measurement or “Or”if the measurement is over the maximum
measurement range.
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Phono jack of
Temperature probe
BNC of pH/ORP
Electrode or ISE

3. CALIBRATION
3.1 pH Calibration
The meter is capable of calibrating up to 3 points using USA or NIST (nSt)
pH buffer standards or 2 points with Low Ionic (Pb) pH buffer standards. All
new calibration values will automatically override existing data.
USA pH 4.01,7.00 and 10.01
NIST pH 4.01, 6.86 and 9.18
Pb pH 4.10 and 6.97
It is recommended that you perform at least a 2-point calibration at room
temperature (25 °C) using standard buffers, starting with the first buffer at pH
7.00 (USA), pH 6.86 (NIST) or pH 6.97 (Pb) followed by other buffer values.
For a 1-point calibration, the calibration should be performed with a pH buffer
value closest to the expected sample value being measured. Otherwise
calibrating at pH 7.00, pH 6.86 or pH 6.97 is advisable.
The meter has automatic buffer recognition that identifies the correct pH
buffer values during calibration. If non-standard pH buffers other than the
above standards are used, or the electrode has worn out, the LCD will flash
“Er1”. Press the CAL key to abort calibration and resume measurement. In
general all pH buffer values have the window of up to +/- 1 pH tolerance
during calibration.
Ensure that you use new pH buffer solutions during calibration. Do not reuse
buffer solutions as they may be contaminated and affect the calibration and
accuracy of measurements. Always store buffer solutions in a dry, cool
environment if possible.
Before use, remove the plastic protective cap on the pH electrode and
condition the glass bulb by soaking it in tap water for 1-2 hours. This hydrates
the glass bulb if the 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 refer to section 5 on Electrode care and maintenance.
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