Myron L TechPro II User manual

18 February 16
TECHPRO
Operation
Manual
MODELS TPH1, TP1
™
®

TechPro
TPH1
BUFFER
°C °F
TDS
pH
COND
09 mar 15
Wrist/neck Strap slot
(Strap user supplied)
pH Sensor
Protective Cap
Up key/Memory Store
Down key/Memory Recall
Displayed here:
• Temperature
readout
• Memory Storage
Location
• pH Calibration
This Key for:
• Calibration
• Memory Clear
• Solution Selection
• Confirmation
These Measurement Keys will:
• Turn instrument on
• Measure parameter
• Exit any function
Icons for pH, Conductivity or
Total Dissolved Solids (TDS)
pH Glass
Electrode
pH Sensor
(User replaceable)
Reference
Junction
(Under Glass
Bulb)
Conductivity Cell
(Built-in
Electrodes)
Temperature
Sensor
Preprogrammed
conductivity/
TDS ratios
For detailed explanations, see Table of Contents
Instrument Illustration
MODEL TPH1 Shown
TDS/SalinityPPT - parts per thousand
µS - microsiemens/cm
(micromhos/cm)
mS - millisiemens/cm
(millimhos/cm)
PPM - parts per million TDS
Conductivity
Conductivity/
Salinity

i
TechPro
TPH1
BUFFER
°C °F
TDS
pH
COND
09 mar 15
Wrist/neck Strap slot
(Strap user supplied)
pH Sensor
Protective Cap
Up key/Memory Store
Down key/Memory Recall
Displayed here:
• Temperature
readout
• Memory Storage
Location
• pH Calibration
This Key for:
• Calibration
• Memory Clear
• Solution Selection
• Confirmation
These Measurement Keys will:
• Turn instrument on
• Measure parameter
• Exit any function
Icons for pH, Conductivity or
Total Dissolved Solids (TDS)
pH Glass
Electrode
pH Sensor
(User replaceable)
Reference
Junction
(Under Glass
Bulb)
Conductivity Cell
(Built-in
Electrodes)
Temperature
Sensor
Preprogrammed
conductivity/
TDS ratios
For detailed explanations, see Table of Contents
Instrument Illustration
MODEL TPH1 Shown
TDS/SalinityPPT - parts per thousand
µS - microsiemens/cm
(micromhos/cm)
mS - millisiemens/cm
(millimhos/cm)
PPM - parts per million TDS
Conductivity
Conductivity/
Salinity

ii

1
I. INTRODUCTION
Thank you for selecting the feature-packed TechPro II™, one of the
Myron L® Company’s latest in an increasing line of instruments utilizing
advanced microprocessor-based circuitry and SMT manufacturing
processes. This circuitry makes the instrument extremely accurate,
reliable and very easy to use.
The TechPro II incorporates several new features including: waterproof
enclosure, keypad calibration, FULL 4 digit LCD, the addition of a 20
location memory storage, and enhanced performance to name just some
of the improvements. Additionally, “salinity” units may be selected. See
Features and Specications on pages 2 & 3.
For your convenience, on the bottom side of your TechPro II is a brief
set of instructions.
Special note ... For the TPH1 & TP1 models, conductivity and TDS
require mathematical correction to 25°C values (ref. Temperature
Compensation, pg. 25). On the left of the TechPro II’s liquid crystal
display is shown an indicator of the salt solution characteristic used to
model temperature compensation (Tempco) of conductivity and its TDS
conversion. The indicator may be KCl, NaCl, or 442™. Selection affects
the temperature correction of conductivity, and the calculation of TDS
from compensated conductivity (ref. Conductivity Conversion to Total
Dissolved Solids (TDS), pg. 28).
The selection can affect the reported conductivity of hot or cold solutions,
and will change the reported TDS of a solution. Generally, using KCl
for conductivity, and 442™ (Natural Water characteristic) for TDS will
reect present industry practice for standardization. This is how your
instrument, as shipped from the factory, is set to operate. For use in sea
water desalination for example, both the CONDuctivity and TDS may
easily be changed to NaCl.

2
II. FEATURES and SPECIFICATIONS
A. Features
• Ranges:
Conductivity/TDS — 0-20,000 µS/ppm (TPH1 & TP1)
pH — 0 -14 (TPH1)
• Superior resolution four (4) digit LCD
• Conductivity/TDS accuracy of ±1% of reading
• pH accuracy of ±.01 pH units (TPH1)
• All electrodes are internal for maximum protection
• Waterproof to 1 meter/3 feet
• Memory storage (20 readings)
• Autoranging Conductivity/TDS (TPH1 & TP1)
• Easy keypad calibration
• Prompts for simple pH calibration (TPH1)
• Factory calibrations stored in microprocessor
• User selectable Conductivity/TDS modes (TPH1 & TP1)
• 3 “User Selectable” solution conversions (tempcos) (TPH1 & TP1)
• User Selectable “Salinity” units (TPH1 & TP1)
• Temperature accuracy of ±0.1°C/F
• Automatic Temperature Compensation to 25°C
• Temperature Compensation disable feature
B. General Specications
Display 4 Digit LCD
Dimensions (LxWxH) 196 x 68 x 64 mm
7.7 x 2.7 x 2.5 in.
Weight 320 g/11.2 oz.
Case Material VALOX
Cond/TDS Cell Material VALOX
Cond/TDS Electrodes 316 Stainless Steel
Cond/TDS Cell Capacity 5 ml/0.2 oz.
pH Sensor Well Capacity 1,2 ml/0.04 oz. (TPH1)
Power 9V Alkaline Battery
Battery Life >100 Hours/5000 Readings
Operating/Storage Temperature 0-55°C/32-132°F
Protection Ratings IP67/NEMA 6
(waterproof to 1 meter/3 feet)
Additional information is available on our website at:
www.myronl.com

3
C. Specication Chart
pH
(TPH1)
Conductivity TDS Temperature
Ranges 0-14 pH 0-9999 µS/cm
10-20 mS/cm in
3 autoranges
0-9999 ppm
10-20 ppt in
3 autoranges
0-71°C
32-160°F
Resolution 0.01 pH 0.1 (<1000 µS)
1.0 (<10 mS)
0.01 (>10 mS)
0.1 (<1000 ppm)
1.0 (<10 ppt)
0.01 (>10 ppt)
0.1°C/F
Accuracy ±0.01 pH ±1% of reading ±0.1°C/F
Auto Temperature
Compensation
0-71°C
32-160°F
0-71°C
32-160°F
Conductivity or
TDS Ratios
KCl, NaCl, or 442™
D. Warranty/Service
The Myron L TechPro II™, excluding the pH sensor (TPH1), has a
Two (2) Year Limited Warranty. The pH sensor (TPH1) has a Six (6)
Month Limited Warranty. If an instrument fails to operate properly, see
Troubleshooting Chart, pg. 22. The battery and pH sensor (TPH1) are
user-replaceable. For other service, return the instrument prepaid to the
Myron L®Company.
MYRON L®COMPANY
2450 Impala Drive
Carlsbad, CA 92010-7226 USA
[phone]
E-Mail: [email protected]
[email protected]
www.myronl.com
If, in the opinion of the factory, failure was due to materials or workmanship,
repair or replacement will be made without charge. A reasonable service
charge will be made for diagnosis or repairs due to normal wear, abuse
or tampering. This warranty is limited to the repair or replacement of the
TechPro II only. The Myron L®Company assumes no other responsibility
or liability.
E. TechPro II™ Series Models
MADE IN USA
TechPro II Models TP1 TPH1
Parameters Conductivity, Conductivity,
TDS & TDS, pH &
Temperature Temperature
*EM Susceptibility: When Measuring 10.0 pH Reference Solution
±0.2 pH in the presence of RF elds ≥ 3 V/m.
±0.37 pH in the presence of RF elds at 300 MHz (±30MHz)
**If either ORP or pH is outside the specied limits, the instrument will display “-Or-”.

4
TABLE OF CONTENTS
Instrument Illustration ...................................... i
I. INTRODUCTION ................................... 1
II. FEATURES and SPECIFICATIONS .................... 2
A. Features ................................ 2
B. General Specications ..................... 2
C. Specication Chart ........................ 3
D. Warranty/Service ......................... 3
E. TechPro II Series Models ................... 3
III. RULES of OPERATION.............................. 6
A. Operation ............................... 6
B. Characteristics of the Keys .................. 6
C. Operation of the Keys ...................... 6
1. Measurement Keys in General ......... 6
2. COND and TDS Keys (TPH1 & TP1) .... 6
3. pH Key (TPH1) .................... 7
4. CAL/MCLR Key .................... 7
5. UP or DOWN Keys .................. 7
IV. AFTER USING the TechPro II ......................... 8
A. Maintenance of the Conductivity Cell
(TPH1 & TP1) ........................ 8
B. Maintenance of the pH Sensor (TPH1) ......... 8
V. SPECIFIC RECOMMENDED MEASURING PROCEDURES . . 8
A. Measuring Conductivity/Total Dissolved Solids .. 8
B. Measuring pH (TPH1) ...................... 8
VI. SOLUTION SELECTION (TPH1 & TP1) ................. 9
A. Why Solution Selection is Available ........... 9
B. The 3 Solution Types....................... 9
C. Calibration of Each Solution Type............. 9
D. Procedure to Select a Solution ............... 9
VII. CALIBRATION ................................... 10
A. Calibration Intervals ...................... 10
B. Rules for Calibration of the TechPro II ........ 10
1. Calibration Steps .................. 10
2. Calibration Limits .................. 11
C. Calibration Procedures
1. Conductivity or TDS Calibration
(TPH1 & TP1) ................. 11
2. Reloading Factory Calibration ........ 12
3. pH Calibration (TPH1) .............. 12
VIII. CALIBRATION INTERVALS ......................... 14
A. Suggested Intervals ...................... 14
B. Calibration Tracking Records ............... 15
C. Conductivity or TDS Practices (TPH1 & TP1)... 15
D. pH Practices (TPH1) ...................... 15

5
IX. MEMORY........................................ 15
A. Memory Storage ......................... 16
B. Memory Recall .......................... 16
C. Clearing a Record/Memory Clear ............ 16
X. TEMPERATURE FORMAT “Centigrade & Fahrenheit” ..... 17
XI. TEMPERATURE COMPENSATION (TC) DISABLE
(TPH1 & TP1) .............................. 17
XII. SALINITY UNITS (TPH1 & TP1) ...................... 18
XIII. TOTAL RETURN to FACTORY SETTINGS.............. 19
XIV. CARE and MAINTENANCE ......................... 19
A. Temperature Extremes .................... 20
B. Battery Replacement (LO BATT) ............ 20
C. pH Sensor Replacement (TPH1) ............ 20
D. Cleaning Sensors ........................ 20
XV. TROUBLESHOOTING CHART ....................... 22
XVI. ACCESSORIES................................... 24
A. Conductivity/TDS Standard Solutions
(TPH1 & TP1) ....................... 24
B. pH Buffer Solutions (TPH1)................. 24
C. pH Sensor Storage Solution (TPH1).......... 24
D. Soft Protective Case ...................... 25
E. Hard Protective Carry Cases ............... 25
F. Replacement pH Sensor (TPH1) ............. 25
XVII. TEMPERATURE COMPENSATION (TPH1 & TP1) ....... 25
A. Standardized to 25°C ..................... 25
B. Tempco Variation......................... 25
C. An Example............................. 26
D. A Chart of Comparative Error ............... 26
E. Other Solutions .......................... 27
XVIII. CONDUCTIVITY CONVERSION to
TOTAL DISSOLVED SOLIDS (TDS) (TPH1 & TP1)... 28
A. How it’s Done ........................... 28
B. Solution Characteristics ................... 28
C. When does it make a lot of difference?........ 28
XIX. TEMPERATURE COMPENSATION (Tempco)
and TDS DERIVATION (TPH1 & TP1) ........... 29
XX. pH MEASUREMENT (TPH1) ........................ 29
A. pH as an Indicator (TPH1) ................. 29
B. pH Units (TPH1) ......................... 30
C. pH Sensor (TPH1) ....................... 30
D. Myron L Integral pH Sensor (TPH1) .......... 31
E. Sources of Error (TPH1) ................... 31
XXI. SOFTWARE VERSION ............................. 32
XXII. GLOSSARY...................................... 33
XXIII. ADDENDUM ..................................... 34
XXIV. NOTES ......................................... 36

6
III. RULES of OPERATION
A. Operation
Using the instrument is simple:
• Individual or multiple parameter readings may be obtained by
lling individual sensors or entire cell cup area.
• Rinse the conductivity cell or pH sensor well (TPH1) with
test solution 3 times and rell. Temperature and/or
measurement extremes will require additional rinses for
maximum accuracy.
• Press the desired measurement key to start measurement.
Pressing the key again restarts the 20 second auto “off” timer.
• Note the value displayed or press the MS key to store the
reading (ref. Memory Storage, pg. 16). It’s that simple!
B. Characteristics of the Keys
• Though your TechPro II has a variety of sophisticated options,
it is designed to provide quick, easy, accurate measurements
by simply pressing one key.
• All functions are performed one key at a time.
• There is no “off” key. After 20 seconds of inactivity the
instrument turns itself off (60 seconds in CAL mode).
• Rarely is it necessary to press and hold a key (as in Procedure
to Select a Solution, pg.9; or Cond. or TDS Calibration, pg. 11).
C. Operation of the Keys (See Instrument Illustration on pg. i)
1. Measurement Keys in General
The measurement keys turn on the instrument in the mode selected.
The parameter is shown at the bottom of the display, and the measurement
units appear at the right. Pressing a measurement key does this even
if you are in a calibration sequence and also serves to cancel a change
(ref. Leaving Calibration, pg. 11).
2. COND and TDS Keys (TPH1 & TP1)
These keys are used with solution in the Conductivity Cell.
Precautions:
• While lling cell cup ensure no air bubbles cling on the cell wall.
• If the proper solution is not selected (KCl, NaCl or 442), (ref.
Why Solution Selection is Available, pg. 9).
a. COND Key
Solution to be tested is introduced into the conductivity cell and a press
of displays conductivity with units on the right. On the left is
shown the solution type selected for conductivity.

7
b. TDS Key
A press of displays Total Dissolved Solids with units on the right.
This is a display of the concentration of material calculated from
compensated conductivity using the characteristics of a known material.
On the left is shown solution type selected for TDS (ref. Solution
Selection, pg. 9).
3. pH Key (TPH1)
Measurements are made on the solution contained in the pH sensor
well (ref. pH Measurement, pg. 29). The protective cap is removed,
and the sensor well is lled and rinsed with the sample enough times to
completely replace the pH Sensor Storage Solution.
After use, the pH sensor well must be relled with Myron L pH Sensor
Storage Solution, and the protective cap reinstalled securely (ref.
Maintenance of the pH Sensor, pg. 8 and pH, pg. 20).
A press of displays pH readings. No units are displayed.
4. CAL/MCLR Key
A press of allows you to enter the calibration mode while
measuring conductivity, TDS or pH. Once in CAL mode, a press of this
key accepts the new value. If no more calibration options follow, the
instrument returns to measuring (ref. Leaving Calibration, pg. 11).
If is held down for 3 seconds, CAL mode is not entered, but
“SEL” appears to allow Solution Selection (ref. pg. 9) with the Up or
Down keys. As in calibration, the CAL key becomes an “accept” key.
While reviewing stored records, the MCLR side of the key is active to
allow clearing records (ref. Clearing a Record/Memory Clear, pg. 16).
5. UP or DOWN Keys
While measuring in any parameter, the or keys activate
the Memory Store and Memory Recall functions.
While in CAL mode, the keys step or scroll the displayed value up or
down. A single press steps the display and holding either key scrolls the
value rapidly.
While in Memory Recall, these keys scroll the display up and down
through the stack of records (ref. Memory Recall, pg. 16).

8
IV. AFTER USING the TechPro II
A. Maintenance of the Conductivity Cell (TPH1& TP1)
Rinse out the cell cup with clean water. Do not scrub the cell. For oily lms,
squirt in a foaming non-abrasive cleaner and rinse. (ref. Conductivity or
TDS, pg. 20). Even if a very active cbhemical discolors the electrodes,
this does not affect the accuracy; leave it alone.
B. Maintenance of the pH Sensor (TPH1)
The sensor well must be kept wet with a solution. Before replacing the
rubber cap, rinse and ll the sensor well with Myron L pH Sensor Storage
Solution. If unavailable, use an almost saturated KCl solution, pH 4 buffer
(ref. pH Buffer Solutions, pg. 24) or a saturated solution of table salt and
tap water. NEVER USE DISTILLED WATER (ref. pH, pg. 20).
V. SPECIFIC RECOMMENDED MEASURING PROCEDURES
Verify proper solution setting (KCl, NaCl, or 442), (ref. Solution Selection, pg. 9).
NOTE: After sampling high concentration solutions or temperature
extremes, more rinsing may be required. When sampling low conductivity
solutions, be sure the pH cap is well seated so that no solution washes
into the conductivity cell from around the pH cap.
A. Measuring Conductivity & Total Dissolved Solids (TDS)
1. Rinse cell cup 3 times with sample to be measured. (This conditions
the temperature compensation network and prepares the cell.)
2. Rell cell cup with sample.
3. Press or .
4. Note value displayed.
B. Measuring pH (TPH1)
1. Remove protective cap by squeezing its at sides and pulling up.
2. Rinse sensor well 3 times with sample to be measured. Shake
out each sample to remove any residual liquid.
3. Rell both sensor wells with sample.
4. Press .
5. Note value displayed.

9
6. IMPORTANT: After use, ll pH sensor well with Myron L pH
Sensor Storage Solution and replace protective cap. If Myron L
pH Sensor Storage Solution is unavailable, use a strong KCl solution,
a pH 4 buffer, or a saturated solution of table salt and tap water (ref.
Cleaning Sensors, 2. pH, pg. 20). Do not allow pH sensor to dry out.
VI. SOLUTION SELECTION (TPH1 & TP1)
A. Why Solution Selection is Available
Conductivity and TDS require temperature correction to 25°C values (ref.
Standardized to 25°C, pg. 25). Selection determines the temperature
correction of conductivity and calculation of TDS from compensated
conductivity (ref. Cond. Conversion to TDS, pg. 28).
B. The 3 Solution Types
On the left side of the display is the salt solution characteristic used to
model temperature compensation of conductivity and its TDS conversion.
Generally, using KCl for conductivity, and 442 (Natural Water characteristic)
for TDS will reect present industry practice for standardization. This is how
your instrument is shipped from the factory (ref. Solution Characteristics,
pg. 28). NaCl may be user selected for either.
C. Calibration of Each Solution Type
There is a separate calibration for each of the 3 solution types. Note
that calibration of a 442 solution does not affect the calibration of a NaCl
solution. For example: Calibration (ref. Conductivity or TDS Calibration,
pg. 11) is performed separately for each type of solution one wishes to
measure (ref. Conductivity/TDS Standard Solutions, pg. 24).
D. Procedure to Select a Solution
NOTE: Check display to see if solution displayed (KCl, NaCl or 442) is
already the type desired. If not:
1. Press or to select the parameter on which
you wish to change the solution type.
2. Press and hold key
for 3 seconds. “SEL” will be
displayed (see Figure 1).
For demonstration purposes,
all 3 solution types are
shown simultaneously.
Figure 1
KCl
442
NaCl

10
3. Use the or key to select type of solution desired
(ref. Solution Characteristics, pg. 28). The selected solution
type will be displayed: KCl, NaCl or 442.
4. Press to accept new solution type.
VII. CALIBRATION
A. Calibration Intervals
Generally, calibration is recommended about once per month with
Conductivity or TDS solutions. Calibration with pH solutions should be
checked twice a month. (ref. CALIBRATION INTERVALS, pg. 14).
B. Rules for Calibration of the TechPro II
1. Calibration Steps
a. Starting Calibration
Calibration is begun by pressing while measuring Conductivity,
TDS or pH. Measuring continues, but the CAL icon is on, indicating
calibration is now changeable.
The reading is changed with the and keys to match the
known value. The calibration for each of the 3 solution types may be
performed in either conductivity or TDS mode.
Depending on what is being calibrated, there may be 1, 2 or 3 steps to
the calibration procedures.
Once in “CAL” mode, the key becomes an “ACCEPT” key. At each
point, pressing accepts the new calibration value and steps you to
the next adjustment (or out of CAL mode if there are no more steps).
In the first six sections, you have learned all
you need to take accurate measurements.
The following sections contain calibration,
advanced operations and technical information.

11
To bypass a calibration step, simply press to accept the present
value as is.
b. Leaving Calibration
Calibration is complete when the “CAL” icon goes out. Pressing any
measurement key cancels changes not yet accepted and exits calibration
mode.
Leaving pH after the 2nd buffer results in the same gain being entered in
place of the 3rd buffer.
2. Calibration Limits
There are calibration limits. A nominal “FAC” value is an ideal value
stored by the factory. Attempts to calibrate too far, up or down, from there
will cause the displayed value to be replaced with “FAC”. If you accept it
(press the “Cal” key) you will have the original default factory calibration
for this measurement. The need to calibrate so far out that “FAC” appears
indicates a procedural problem, incorrect standard solution, a very dirty
cell cup or an aging pH sensor (ref. Troubleshooting Chart, pg. 22).
C. Calibration Procedures
1. Conductivity or TDS Calibration (TPH1 & TP1)
a. Rinse conductivity cell three times with proper standard (KCl,
NaCl, or 442) (ref. Cond/TDS Standard Solutions, pg. 24).
b. Rell conductivity cell with same standard. KCl-7000 used in
Figure 2, pg. 11.
c. Press or , then press , “CAL” icon will appear
on the display (see Figure 2).
d. Press or to step
the displayed value toward the
standard’s value (7032 >7000)
or hold a key down to scroll
rapidly through the reading.
e. Press once to conrm new value and end the calibration
sequence for this particular solution type. If another solution type is
also to be measured, change solution type now and repeat this
procedure.
Figure 2
°C
KCl
COND
CAL

12
2. Reloading Factory Calibration (Cond or TDS)
If calibration is suspect or known to be incorrect, and no standard solution
is available, the calibration value can be replaced with the original factory
value for that solution. This “FAC” value is the same for all TechPro IIs,
and returns you to a known state without solution in the cell. The “FAC”
internal electronics calibration (which bypasses the electrodes and cell) is
not intended to replace calibration with conductivity standard solutions. If
another solution type requires resetting, change solution type and repeat
this procedure.
a. Press or .
b. Press .
c. Press key until “FAC” appears and release.
d. Press to accept the factory calibration setting.
3. pH Calibration (TPH1)
Important: Always “zero” your TechPro II with a pH 7 buffer solution
before adjusting the gain with acid or base buffers, i.e., 4 and/or 10.
a. pH Zero Calibration (TPH1)
1. Rinse sensor well 3 times with 7 buffer solution.
2. Rell both sensor wells with 7 buffer solution.
3. Press to verify the pH
calibration. If the display
shows 7.00, skip the pH Zero
Calibration and proceed to
section b. pH Gain Calibration.
4. Press to enter calibration
mode. The “CAL”, “BUFFER” and “7” annunciators will appear
(see Figure 3). Displayed value will be the uncalibrated sensor.
NOTES: If a wrong buffer is added (outside of 6-8 pH), “7” and “BUFFER”
Figure 3
BUFFER
pH
CAL

13
will ash, and the TechPro II will not adjust. The uncalibrated pH value
displayed in step 4 will assist in determining the accuracy of the pH sensor.
If the pH reading is above 8 with pH 7 buffer solution, the sensor well needs
additional rinsing or the pH sensor is defective and needs to be replaced .
5. Press or until the display reads 7.00.
NOTE: Attempted calibration of >1 pH point from
factory calibration will cause “FAC” to appear. This indicates the need for
sensor replacement (ref. Troubleshooting pg. 22) or fresh buffer solution.
The “FAC” internal electronic calibration is not intended to replace
calibration with pH buffers. It assumes an ideal pH sensor. Each “FAC”
indicates a factory setting for that calibration step (i.e., 7, acid, base).
You may press to accept the preset factory value, or you may
reduce your variation from factory setting by pressing or .
6. Press to accept the new value. The pH Zero Calibration
is now complete. You may continue with pH Gain Calibration or
exit by pressing any measurement key.
b. pH Gain Calibration (TPH1)
Important: Always calibrate or verify your TechPro II with a pH 7 buffer
solution before adjusting the gain with acid or base buffers, i.e., 4 and/or
10, etc. Either acid or base solution can be used for the 2nd point “Gain”
calibration and then the opposite for the 3rd point. The display will verify
that a buffer is in the sensor well by displaying either “Acd” or “bAS”.
1. The pH calibration mode is initiated by either completion of the
pH Zero Calibration, or verifying 7 buffer and pressing the
key twice while in pH measurement mode.
2. At this point the “CAL”, “BUFFER” and “Acd” or “bAS”
annunciators will be displayed (see Figures 4 and 5).
Figure 4
BUFFER
pH
CAL
Figure 5
pH
BUFFER
CAL

14
NOTE: If the “Acd” and “bAS” indicators are blinking, the unit is indicating an
error and needs either an acid or base solution present in the sensor well .
3. Rinse sensor well 3 times with acid or base buffer solution.
4. Rell sensor well again with same buffer solution.
5. Press or until display agrees with buffer value.
6. Press to accept 2nd point of calibration. Now the display
indicates the next type of buffer to be used.
Single point Gain Calibration is complete. You may continue for the 3rd
point of Calibration (2nd Gain) or exit by pressing any measurement key.
Exiting causes the value accepted for the buffer to be used for both acid
and base measurements.
To continue with 3rd point calibration, use base buffer if acid buffer was
used in the 2nd point, or vice-versa. Again, match the display to the
known buffer value as in step 2 and continue with the following steps:
7. Repeat steps 3 through 5 using opposite buffer solution.
8. Press to accept 3rd point of calibration, which completes
the Calibration procedure. Fill sensor well with Myron L pH
Sensor Storage Solution and replace protective cap.
VIII. CALIBRATION INTERVALS
There is no simple answer as to how often one should calibrate
an instrument. The TechPro II is designed to not require frequent
recalibration. The most common sources of error were eliminated in
the design, and there are no mechanical adjustments. Still, to ensure
specied accuracy, any instrument must be checked against chemical
standards occasionally.
A. Suggested Intervals
On the average, we expect calibration need only be checked monthly
for the Conductivity or TDS functions. The pH (TPH1) function should be
checked every 2 weeks to ensure accuracy. Measuring some solutions
will require more frequent intervals.

15
B. Calibration Tracking Records
To minimize your calibration effort, keep records. If adjustments you
are making are minimal for your application, you can check less often.
Changes in conductivity calibration should be recorded in percent.
Changes in pH calibration (TPH1) are best recorded in pH units.
Calibration is purposely limited in the TechPro II to ±10% for the
conductivity cell, as any change beyond that indicates damage, not
drift. Likewise, calibration changes are limited to ±1 pH unit (TPH1), as
any change beyond that indicates the end of the sensor’s lifetime and
replacement is recommended.
C. Conductivity, RES, TDS Practices to Maintain Calibration
1. Clean oily lms or organic material from the cell electrodes with
foaming cleaner or mild acid. Do not scrub inside the cell.
2. Calibrate with solutions close to the measurements you make.
Readings are compensated for temperature based on the
type of solution. If you choose to measure tap water with a KCl
compensation, which is often done (ref. Temperature Compensation,
pg. 25), and you calibrate with 442 solution because it is handy,
the further away from 25°C you are, the more error you have.
Your records of calibration changes will reect temperature
changes more than the instrument’s accuracy.
3. Rinse out the cell with pure water after taking measurements.
Allowing slow dissolving crystals to form in the cell contaminates
future samples.
4. For maximum accuracy, keep the pH sensor cap on tight so
that no uid washes into the conductivity cell.
D. pH Practices to Maintain Calibration (TPH1)
1. Keep the sensor wet with Myron L pH Sensor Storage Solution.
2. Rinse away caustic solutions immediately after use.
IX. MEMORY
This feature allows up to 20 readings with their temperatures to be stored
simultaneously for later recall.

16
A. Memory Storage
1. While displaying a measurement, press to record the
displayed value.
2. “MEMORY” will appear and the
temperature display will be
momentarily replaced by a
number (1-20) showing the
position of the record. Figure
6 shows a reading of 1806 µS
stored in memory record #4.
B. Memory Recall
1. Press any measurement key.
2. Press , “MEMORY” will appear, and the display will show
the last record stored.
3. Press or to scroll to the record location desired
(the temperature display alternates between temperature
recorded and location number).
4. Press any measurement key to leave memory recall or allow to
automatically turn off.
C. Clearing a Record/Memory Clear
After recalling a certain record location, press to clear that
memory. This space will be the place for the next memory record, unless
you scroll to another empty position before ending the recall sequence.
The next memory stored will go into the next highest available memory
location.
Example: You have locations 1-7 lled, and wish to clear the conductivity
reading stored in record location #3and replace it with a pH reading.
1. Press and scroll to location #3.
2. Press to clear old record #3.
Figure 6
°C
KCl
COND
MEMORY