for programming
special
temperature
compensation
factor and
conductivity/TDS
ratio
Displayed here:
• Temperature
readout
• USER temperature
compensation or
conductivity/TDS
ratio
• Memory Storage/
Recall
• pH Calibration
ORP
Electrode
pH Glass
Electrode
pH/ORP Sensor
(Replaceable)
For detailed explanations see Table of Contents
Instrument
Illustration
Temperature
Sensor
MODEL 6P Shown
Time & Date
displayed here
TEST Value
iii1
I. INTRODUCTION
Thank you for selecting the feature-packed Ultrameter 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 Ultrameter II incorporates several new features including a clock
with time and date, an increased memory of up to 100 locations with
time and date stamp, the ability of the user to adjust the timeout “Auto
OFF”, and enhanced performance. See Features and Specications on
pages 2 & 3.
The most exciting new feature is data logging with the ability to download
the memory or stored test data with its corresponding time and date.
This feature allows the user to create spreadsheets and graphs with
ease, and quickly and accurately manipulate data more effectively. The
optional uDock™ and software is compatible with most computers using
either Microsoft Windows XP or 2000™, or Macintosh OS9.2 or OSX™.
The data may be imported into a variety of spreadsheet formats like
Microsoft Excel CSV™.
Please Note: Although the Myron L Company has performed extensive
testing, we cannot guarantee compatibility of all applications and formats.
We suggest testing your application and format for compatibility before
relying on it.
For your convenience, on the bottom side of your Ultrameter II is a
brief set of instructions. A waterproof pocket sized card with abbreviated
instructions is also included with the instrument.
Special note ...... Conductivity, resistivity, and TDS require mathematical
correction to 25°C values (ref. Temperature Compensation, pg. 37). On
the left of the Ultrameter II’s liquid crystal display is shown an indicator of
the salt solution characteristic used to model temperature compensation
of conductivity and its TDS conversion. The indicator may be KCl,
NaCl, 442™ or USER. Selection affects the temperature correction of
conductivity, and the calculation of TDS from compensated conductivity
(ref. Conductivity Conversion to Total Dissolved Solids (TDS), pg. 40).
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, NaCl for resistivity, and 442 (Natural Water characteristic)
for TDS will reect 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.
II. FEATURES and SPECIFICATIONS
A. Features
• Superior resolution 4 digit LCD displays full 9999 µS/ppm.
• Accuracy of BETTER than ±1% of reading in a handheld instrument.
• All electrodes are internal for maximum protection.
• Improved 4 electrode sensor technology.
• Waterproof to 1 meter/3 feet.
• Autoranging conductivity/TDS/resistivity.
• Prompts for easy pH calibration (6P).
• Factory calibrations stored in microprocessor.
• 3 conductivity/TDS solution conversions preprogrammed into
microprocessor.
• USER mode feature allows:
Programming your own cond/TDS conversion factor.
Programming your own temperature compensation factor.
Disabling temperature compensation.
• Real Time Clock with Time and Date.
• Data Logging with TIME and DATE in memory.
• Memory stores 100 readings.
• Download capability with optional uDock™.
• User adjustable timeout “Auto OFF”.
B. General Specications
Display 4 Digit LCD
Dimensions (LxWxH) 196 x 68 x 64 mm/
7.7 x 2.7 x 2.5 in.
Weight 352 g/12.4 oz.
Case Material VALOX*
Cond/Res/TDS Cell Material VALOX*
Cond/TDS Electrodes (4) 316 Stainless Steel
Cond/Res/TDS Cell Capacity 5 ml/0.2 oz.
pH/ORP Sensor Well Capacity 1,2 ml (6P)/0.04 oz.
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)
* ™ SABIC Innovative Plastics IP BV
Additional information is available on our website at:
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 Ultrameter II only. The Myron L Company assumes
no other responsibility or liability.
• Individual or multiple parameter readings may be obtained by
lling individual sensors or entire cell cup area.
• Rinse the conductivity cell or pH/ORP sensor (6P) well with
test solution 3 times and rell. 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 15 second auto “off” timer.
• Note the value displayed or press the MS key to store the
reading (ref. Memory Storage, pg. 21). It’s that simple!
B. Characteristics of the Keys
• Though your Ultrameter 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 15 seconds of inactivity the
instrument turns itself off (60 seconds in CAL mode). User
adjustable up to 75 seconds.
• Rarely is it necessary to press and
to Select a Solution, pg. 11; or Cond. or TDS Calibration, pg. 15).
C. Operation of the Keys (See Instrument Illustration on pg. i)
1. Measurement Keys in General
Any of the 5 measurement keys in the upper part of the keypad turns on
the instrument in the mode selected. The mode 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. 14).
2. COND, RES and TDS Keys
These 3 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, 442 or USER),
refer to Why Solution Selection is Available, pg. 11 and
Procedure to Select a Solution, pg. 11.
a. COND Key
Solution to be tested is introduced into the conductivity cell and a press
hold
a key (as in Procedure
of displays conductivity with units on the right. On the left is
shown the solution type selected for conductivity.
7
b. RES Key
A press of displays resistivity with units on the right. On the left
is shown solution type selected for resistivity (ref. Solution Selection, pg.
11). The range of display of resistivity is limited to between 10 kilohms
(KΩ) and 30 megohms (MΩ). A solution outside that range will only
show [- - - -] in the display.
c. 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. 11).
3. pH and ORP Keys
Measurements are made on solution held in the pH/ORP sensor well
(ref. pH and ORP, pg. 43). The protective cap is removed and the sensor
well is lled and rinsed with the sample enough times to completely
replace the storage solution.
After use, the pH/ORP sensor well must be relled with Myron L Storage
Solution, and the protective cap reinstalled securely (ref. Maintenance
of the pH/ORP Sensor, pg. 9 and Cleaning Sensors, 2. pH/ORP, pg. 32).
a. pH Key (6P)
A press of displays pH readings. No units are displayed on the
right.
b. ORP Key (6P)
A press of displays Oxidation-Reduction Potential/REDOX
reading in millivolts, “mV” is 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. 14).
If is held down for about 3 seconds, CAL mode is not entered,
but “SEL” appears to allow Solution Selection (ref. pg. 11) with the Up or
Down keys. As in calibration, the CAL key is now 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. 21).
8
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, the keys scroll the display up and down through
the stack of records (ref. Memory Recall, pg. 21).
IV.AFTER USING the Ultrameter IIA. Maintenance of the Conductivity Cell
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. Cleaning
Sensors, pg. 32). Even if a very active chemical discolors the electrodes,
this does not affect the accuracy; leave it alone.
B. Maintenance of the pH/ORP Sensor (6P)
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 Storage
Solution. If unavailable, use an almost saturated KCl solution, pH 4
buffer or a saturated solution of table salt and tap water (ref. pH and
ORP Practices, pg. 20). NEVER USE DISTILLED WATER.
V. SPECIFIC RECOMMENDED MEASURING
PROCEDURES
If the proper solution is not selected (KCl, NaCl, 442 or USER), see
Solution Selection, pg. 11.
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. Rell cell cup with sample.
3. Press or .
9
4. Take reading. A display of [- - - -] indicates an overrange
condition.
B. Measuring Resistivity
Resistivity is for low conductivity solutions. In a cell cup the value may
drift from trace contaminants or absorption from atmospheric gasses, so
measuring a owing sample is recommended.
1. Ensure pH protective cap is secure to avoid contamination.
2. Hold instrument at 30° angle (cup sloping downward).
3. Let sample ow continuously into conductivity cell with no
aeration.
4. Press key; use best reading.
NOTE: If reading is lower than 10 kilohms display will be dashes:
[ - - - - ]. Use Conductivity.
C. Measuring pH (6P)
1. Remove protective cap by squeezing its 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. Rell both sensor wells with sample.
4. Press .
5. Note value displayed.
6. IMPORTANT: After use, ll pH/ORP 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/ORP, pg.
32).
D. Measuring ORP (6P)
1. Remove protective cap by squeezing its sides and pulling up.
2. Rinse sensor well 3 times with sample to be measured. Shake
out each sample to remove any residual liquid.
10
Do not allow pH/ORP sensor to dry out.
3. Rell both sensor wells with sample.
4. Press .
5. Take reading.
6. IMPORTANT: After use, ll pH/ORP 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/ORP, pg.
32).
VI. SOLUTION SELECTION
A. Why Solution Selection is Available
Conductivity, resistivity, and TDS require temperature correction to
25°C values (ref. Standardized to 25°C, pg. 38). Selection determines
the temperature correction of conductivity and calculation of TDS from
compensated conductivity (ref. Cond. Conversion to TDS, pg. 40).
B. The 4 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, NaCl for resistivity, and 442 (Natural
Water characteristic) for TDS will reect present industry practice for
standardization. This is how your instrument is shipped from the factory
(ref. Solution Characteristics, pg. 40).
Do not allow pH/ORP sensor to dry out.
The USER selection allows a custom value to be entered for the
temperature compensation of conductivity and also the conversion ratio
if measuring TDS.
C. Calibration of Each Solution Type
There is a separate calibration for each of the 4 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. 15) is performed separately for each type of solution one wishes to
measure (ref. Conductivity/TDS Standard Solutions, pg. 36).
D. Procedure to Select a Solution
NOTE: Check display to see if solution displayed (KCl, NaCl, 442 or
USER) is already the type desired. If not:
1. Press , or to select the parameter on which
11
you wish to change the
Figure 1
KCl
442
NaCl
User
Figure 2
°C% /
User
COND
solution type.
2. Press and hold key
for 3 seconds to make
“SEL” appear (see Figure
1). For demonstration
purposes, all 4 solution
types are shown simultaneously.
3. Use the or key to select type of solution desired
(ref. Solution Characteristics, pg. 40). The selected solution
type will be displayed: KCl, NaCl, 442 or User.
4. Press to accept new solution type.
E. Application of USER Solution Type
1. User Programmable Temperature Compensation
(Tempco)
This feature allows you to change your Ultrameter II’s temperature
compensating factor to another factor between 0-9.99%/°C (ref.
Temperature Compensation, pg. 37). This feature does not apply to pH
or ORP.
a. As in Procedure to Select a Solution, pg. 11, select “USER”
mode.
b. With “USER” mode now selected, press . You may now
adjust a temperature compensation from .00%/°C to 9.99%/°C,
by pressing or .
See example in Figure 2.
c. Press twice to skip
calibration adjustment and
accept the new tempco (3
times if in TDS mode). You
are now ready to measure
samples with your new temperature compensation factor.
12
2. Disabling Temperature Compensation
Figure 3
°C% /
User
COND
Figure 4
RATIO
User
TDS
In these first six sections, you have learned
all you need to make accurate measurements.
The following sections contain calibration,
advanced operations and technical information.
a. Select USER mode, see Procedure to Select a Solution, pg. 11.
b. With “USER” selected, press . If the display does not
show .00%/°C, hold long enough to bring the tempco to
.00%/°C (see Figure 3).
c. Press twice
(3 times if in TDS mode).
Temperature compensation
is now disabled (=0) for
measurements in USER mode.
3. User Programmable Conductivity to TDS Ratio
This feature allows you to select a custom conductivity to TDS conversion
ratio within the range of 0.20-7.99 for USER mode measurements.
To determine the conversion ratio for a custom solution of known TDS ppm
value, measure the solution conductivity at 25ºC with the Ultrameter II and
divide the ppm value by the µS value. For example, a solution of known 75ppm
TDS and measured 100µS conductivity at 25ºC would have a conversion
ratio of 75/100 or 0.75. Enter the new conversion ratio as follows:
a. While in “USER” mode, press .
b. Press twice (to skip over tempco adjustment) and
“RATIO” will appear (see Figure 4).
c. Adjust with or
key until new conversion
ratio is displayed.
d. Press twice (to skip over calibration adjustment) to
accept new conversion ratio. You are now ready to measure
samples with the new conductivity/TDS ratio.
13
VII.CALIBRATION
KCl, NaCl or 442User
Cond Gain only Tempco, then Gain
Res Done in conductivityDone in conductivity or TDS
TDS Gain only Tempco, Ratio, then Gain
pH 7, acid and/or base (6P)
ORP Zero set with pH 7 automatically (6P)
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. Calibration of ORP is not necessary (ref.
CALIBRATION INTERVALS, pg. 19).
B. Rules for Calibration of the Ultrameter 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 4 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).
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
14
measurement key cancels changes not yet accepted and exits calibration
Figure 5
°C
KCl
COND
CAL
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/ORP sensor (ref. Troubleshooting Chart, pg.
34).
C. Calibration Procedures
1. Conductivity or TDS Calibration
a. Rinse conductivity cell three times with proper standard (KCl,
NaCl, or 442) (ref. Cond/TDS Standard Solutions, pg. 36). For
user calibration see User Calibration Conductivity/TDS below.
b. Rell conductivity cell with same standard. KCl-7000 shown.
c. Press or , then
press , “CAL” icon will
appear on the display
(see Figure 5).
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 conrm 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.
2. User Calibration Conductivity/TDS
Instrument must be in USER mode, see Solution Selection, pg. 11.
15
a. Rinse conductivity cell three times with your standard.
b. Rell conductivity cell with same standard.
c. Press or , then press twice in COND/three
times in TDS. The “CAL” icon will appear on the display.
d. Press or to step the displayed value toward the
standard’s value or hold a key down to scroll rapidly through
the reading.
e. Press once to conrm new value and end the
calibration sequence for this particular solution type.
3. Resistivity Calibration
Resistivity is the reciprocal of Conductivity. Resistivity is calibrated only
if conductivity is calibrated for the same solution type.
4. 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 Ultrameter 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 . (If in USER solution mode, press CAL key
twice if in Conductivity, and three times if in TDS to skip over
tempco and ratio adjustments.)
c. Press key until “FAC” appears and release.
d. Press to accept the factory calibration setting.
16
5. pH Calibration (6P)
Figure 6
BUFFER
pH
CAL
Important: Always “zero” your Ultrameter II with a pH 7 buffer solution
before adjusting the gain with acid or base buffers, i.e., 4 and/or 10, etc.
a. pH Zero Calibration (6P)
1. Rinse sensor well 3 times with 7 buffer solution.
2. Rell 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 6). Displayed
value will be the uncalibrated sensor.
NOTES: If a wrong buffer is added (outside of 6-8 pH),“7” and “BUFFER”
will ash, and the Ultrameter 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. 34) 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
17
reduce your variation from factory setting by pressing or
Figure 7
BUFFER
pH
CAL
Figure 8
pH
BUFFER
CAL
.
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 (6P)
Important: Always calibrate or verify your Ultrameter 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 7 and 8).
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. Rell sensor well again with same buffer solution.
5. Press or until display agrees with buffer value.
18
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 basic buffer if acidic 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 6 using opposite buffer solution.
8. Press to accept 3rd point of calibration, which
completes the Calibration procedure. Fill sensor well with
Myron L Storage Solution and replace protective cap.
6. ORP Calibration (6P)
ORP electrodes rarely give false readings without problems in the
reference electrode. For this reason, and because calibration solutions
for ORP are highly reactive and potentially hazardous, your Ultrameter II
has an electronic ORP calibration. This causes the zero point on the
reference electrode to be set whenever pH 7 calibration is done.
7. Temperature Calibration
Temperature calibration is not necessary in the Ultrameter II.
VIII. CALIBRATION INTERVALS
There is no simple answer as to how often one should calibrate an
instrument. The Ultrameter 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
specied 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, RES or TDS functions. The pH (6P) function should be
checked every 2 weeks to ensure accuracy. Measuring some solutions
will require more frequent intervals.
19
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 (6P) are best recorded in pH units.
Calibration is purposely limited in the Ultrameter 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 (6P), 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. An Example, pg. 38),
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 reect 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 and ORP Practices to Maintain Calibration (6P)
1. Keep the sensor wet with Myron L Storage Solution.
2. Rinse away caustic solutions immediately after use.
ORP calibration solutions are caustic, and ±5% is considered very
accurate. By using the pH zero setting (0 mV = 7 pH) for ORP and
precision electronics for detection, the Ultrameter II delivers better
accuracy without calibration than a simpler instrument could using
calibration solutions.
20
IX. MEMORY
Figure 9
°C
KCl
COND
MEMORY
This feature allows up to 100 readings with their temperatures to be
stored simultaneously for later recall. At the same time, the TIME and
DATE are also recorded. To download the memory to a computer, (ref.
uDock™ IR Data Port, pg. 30).
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 (1-100)
showing the position of the record. Figure 9 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 to display time and date stamp.
5. Press any measurement key to leave memory recall or allow to
automatically turn off.
C. Clearing a Record/Memory ClearAfter recalling a certain record location, press and HOLD 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 #3 and replace it with a pH reading.
21
1. Press and scroll to location #3.
Figure 10
MEMORY
Figure 11
CAL
2. Press and HOLD to clear old record #3.
3. Fill pH/ORP sensor well with sample.
4. Press to measure sample and press to store
reading in location #3.
5. The next memory stored will go into location #8.
6. To clear all records: After
pressing , scroll down.
“CLr ALL” will be displayed (see Figure 10).
7. Press . All records will
be cleared.
X. TIME and DATE
The Time and Date may easily be changed as you travel.
A. Setting TIME
Time is always displayed in 24 hour time.
Example shown in Figure 11, 16:05 equals 4:05 PM.
1. Press .
2. Press until the time is displayed (stored readings, PC
OFF, CLr ALL, time i.e.
“16:05”).
3. Press to initiate. CAL
will be displayed along with
the time, (see Figure 11).
22
4. Press the or to change the time.
Figure 12
Figure 13
CAL
Figure 14
CAL
5. Press to accept the change (new time).
B. Setting DATE
Example shown in Figure 12,
is in US format i.e. mo/dy/yr.
NOTE: The default format is US.
Date format may be changed
(ref. Date Format “US and
International (Int)”, pg. 24).
1. Press .
2. Press repeatedly until the date is displayed (stored
readings, PC OFF, CLr ALL, time, date, i.e. 01.05/05(January 5, 2005)).
3. Press to initiate. CAL will be displayed along with the
YEAR, (see Figure 13).
4. Press or to
change the YEAR.
5. Press to accept the
change (new year).
6. Press or to
change the month.
7. Press to accept the
change (new month),
(see Figure 14).
23
8. Press the or
Figure 15
CAL
Figure 16
Figure 17
to change the day.
9. Press to accept
the change (new day)
(see Figure 15).
C. DATE FORMAT “US & International (Int)”
1. Press .
2. Press repeatedly until the format is displayed (stored
readings, PC OFF, CLr ALL, time, date, date format).
3. Press to change. Display will now indicate other format
(see Figures 16 & 17).
4. Press any measurement key or allow to automatically turn off.
XI. TEMPERATURE FORMAT “Centigrade & Fahrenheit”
1. Press .
2. Press to display the stored memory records.
3. Press repeatedly until you pass the “US” or “Int” date
24
format location. The display will show a “C” or “F”
Figure 18
Figure 19
Figure 20
(see Figures 18 and 19).
4. Press to switch units.
5. Press to accept unit preference for all temperature
readings.
NOTE: Tempco will still be shown in %/°C
.
XII. TOTAL RETURN to FACTORY SETTINGS “FAC SEL”
There may come a time when it would be desirable to quickly reset
all the recorded calibration values in the instrument back to the factory
settings. This might be to ensure all calibrations are set to a known
value, or to give the instrument to someone else free of adjustments or
recorded data for a particular application.
NOTE: All stored data will be lost.
1. Press .
2. Press to display the stored memory records.
3. Press repeatedly
until you pass the CLr ALL
and the C-F locations. The
display will show a “FAC SEL” (see Figure 20).
4. Press to accept the resetting. Display will return to Cond.
25
XIII. CELL CHECK
Figure 21
Figure 22
Figure 23
Figure 24
The cell check veries the cleanliness of the conductivity/TDS/resistivity
sensor. In normal use the cell may become dirty or coated and require
cleaning. If the display is showing “.00” when the cell cup is dry, the
sensor is probably clean. However, when testing high purity water in
resistivity (RES) mode improved accuracy may be desired. No matter
what a manufacturer claims, a sensor can and will become contaminated
or coated; therefore require cleaning. A true 4-wire sensor, as in the
Ultrameter II, helps to mitigate contamination, but NO SENSOR IS
100% IMMUNE.
1. Press .
2. Press to display the
stored memory records.
3. Press repeatedly until
you pass the FAC SELlocation. The display will
show a “CELL ch”
(see Figure 21).
4. Press to test.
If cell is clean, Good will momentarily be displayed
(see Figure 22). If cell is
dirty, CELL cLn will be
displayed (see Figure 23),
(ref. Cleaning Sensors,
pg. 32).
XIV. AUTO OFF
Auto off allows the user to adjust the
time the instrument is ON (up to 75
seconds) after each press of a key.
Default time is 15 seconds with 60
seconds in CAL (calibration) mode.
1. Press .
26
2. Press to display the stored memory records.
Figure 25
CAL
Figure 26
CAL
3. Press repeatedly until you pass the CELL ch location.
The display will show “Auto oFF” (see Figure 24).
4. Press to initiate. CAL
will be displayed along with
the “15 SEC” (see Figure
25).
5. Press or to
change the time (see
Figure 26). Maximum
time is shown.
6. Press to accept the
change (new time).
XV. USER MODE CALIBRATION LINC™ FUNCTION
Linc™ function allows easy calibration when in User mode and the user
does not have a user standard solution to calibrate the instrument. This
function will ensure more repeatable and accurate measurements than
many other calibration methods. It is recommended that this function be
used to provide the highest degree of condence when the Ultrameter II
is used in “User” mode. When Linc is used, the User mode is linked to
another standard, i.e. if User and KCl are linked, a KCI standard solution
is used to calibrate the instrument. It is that simple.
A. Calibration of Ultrameter II for use in User Mode
1. Press or key.
2. Calibrate the unit using a Standard Solution, (ref.
CALIBRATION, pg. 14).
3. Place the Ultrameter II in User mode, (ref. SOLUTION SELECTION, pg. 11).
27
4. Verify/Set the calibration linc. (See below – Setting User Mode
Figure 27
Figure 28
User
Figure 29
KCl
User
Calibration Linc).
B. Setting User Mode Calibration “Linc”
The Linc function sets or “links” the calibration gain factor of a Standard
Solution to the User solution mode. Once set, the “Linc” will stay intact
with future calibrations unless the Linc has been canceled. For more
information on canceling the User Mode Calibration Linc refer to the
section “Canceling User Mode Calibration Linc”, pg. 29.
Follow the steps below to set either the KCl, NaCl or 442 calibration
factor to the User solution mode.
1. Press measurement key desired to be “Linked”, i.e. ,
or .
2. Place the Ultrameter II in
User mode, (ref. SOLUTION
SELECTION, pg. 11, for
selecting the User Mode).
3. Press arrow key until
the menu “Linc” appears
(see Figure 27).
4. Press key. The
instrument will display “SEL”
and the “User” Icon (see
Figure 28).
Any additional display of KCl,
NaCl or 442 icons indicates a “Linc”
between the User solution and the
other solution displayed.
5. Press or keys
to select a Standard
Solution to be linked to the
User mode calibration
constant, (see Figure 29). User linked to KCl.
If none of the Solution Selection icons are displayed, (i.e. KCl, NaCl or
442) nothing has been linked to User mode.
28
6. Press key to accept the setting. Pressing any of the
measurement keys will exit without changing the setting. User
mode “Linc” is now complete. The User mode will now use the
calibration gain constant used for the calibration of the
Standard Solution as outlined above.
C. Canceling User Mode Calibration “Linc”
The Ultrameter II must be in User linked mode in order to cancel the
“Linc”, (ref. SOLUTION SELECTION, pg. 11).
1. Press “Linked” measurement key , or .
Two solution icons will be shown in the left side of display “User” and another, i.e., “KCl”.
2. Press key until the menu “Linc” appears, (see
Figure 27).
3. Press key, the instrument will display both “SEL” and
the “User” Icon.
4. Press key until “User” is the only solution icon being
displayed.
5. Press key.
6. The User mode calibration “Linc” has now been canceled.
NOTES:
1. To maintain repeatability, use the same standard solutions for future
calibrations.
2. Calibration of the Ultrameter II Gain Factor for User mode is not
available when the calibration linc has been established. The other
calibration functions (i.e. Temperature Compensation %/C settings and
TDS Ratio settings) are still intact. To perform a calibration of the User
mode as described in User Calibration Conductivity/TDS, pg. 15, the
User Mode Linc should be canceled. See above Canceling User Mode
calibration “Linc”.
3. Once a “Linc” has been established for User mode, the “Linc” will apply
29
to all measurement modes using User solution selection (i.e. TDS/User,
Figure 30
Cond/User or Res/User).
XVI. uDock™ IR DATA PORT INSTRUCTIONS
Requires Myron L uDock™ accessory package, Model # U2CIP.
The Myron L uDock is powered via the USB port, requiring no external
power source. The uDock application will operate on Windows 2000 &
XP*, and Macintosh OS9.2 & OSX** based computer systems.
A. Software Installation
1. Place Myron L Ultrameter II uDock Installation CD into your computer.
2. Upon opening, select the folder for your operating system.
3. Install uDock application. See detailed installation instructions
on CD.
4. Additional drivers may be required. See our website for the
latest information.
B. Hardware Setup
1. Connect USB cable (provided with uDock) to your computer.
Assuming your computer is on, the uDock GREEN LED will
illuminate indicating there is power to the uDock and that a
proper connection has been made.
C. Memory Stack Download
1. Launch the application using the uDock icon.
2. Select the proper comm port setting (rst time only).
3. Place CLEAN, DRY Ultrameter II on uDock.
4. Press key.
5. Press and HOLD
key until the menu “PC
OFF” appears, (see
Figure 30).
30
6. Press key. “PC On”
Figure 31
Figure 32
will be displayed, (see
Figure 31). The GREEN
LED on the uDock will now
be blinking periodically,
indicating communication
has been established
between the Ultrameter IIand the uDock.
NOTE. “PC Ini” may momentarily be
displayed while initializing, (see
Figure 32).
7. On your computer, click on
the data download button. A
data transfer bar will appear
while the data is being downloaded.
Once downloaded, the data may be manipulated, printed or stored within
the Myron L uDock application, or the data may be exported to another
more powerful spreadsheet † such as Excel*.
† Please Note: Although the Myron L Company has performed extensive
testing, we cannot guarantee compatibility of all applications and formats.
We suggest testing your application and format for compatibility before
relying on it.
Additional features such as setting time and date and erasing data are
available. See uDock software installation CD or visit www.myronl.com
for the latest instructions.
8. Upon completion, click on the “disconnect” icon.
9. Turn off Ultrameter II PC download mode by selecting any
measurement function. Failure to do so will reduce battery life.
31
XVII. CARE and MAINTENANCE
Ultrameter IIs should be rinsed with clean water after use. Solvents should
be avoided. Shock damage from a fall may cause instrument failure.
A. Temperature Extremes
Solutions in excess of 71°C/160°F should not be placed in the cell
cup area; this may cause damage. The pH sensor may fracture if the
Ultrameter II temperature is allowed to go below 0°C/32°F. Care should
be exercised not to exceed rated operating temperature.
Leaving the Ultrameter II in a vehicle or storage shed on a hot day
can easily subject the instrument to over 66°C/150°F. This will void the
warranty.
B. Battery Replacement
Dry Instrument THOROUGHLY. Remove the four (4) bottom screws.
Open instrument carefully. Carefully detach battery from circuit board.
Replace with 9 volt alkaline battery. Replace bottom, ensuring the
sealing gasket is installed in the groove of the top half of case. Re-install
screws, tighten evenly and securely.
NOTE: Because of nonvolatile EEPROM circuitry, all data stored in
memory and all calibration settings are protected even during power
loss or battery replacement. However, loss of time and date may occur if
battery is removed for longer than 3 minutes (180 seconds).
C. pH/ORP Sensor Replacement (6P)
Order model RPR. When ordering, be sure to include the model and
serial number of your instrument to ensure receipt of the proper type.
Complete installation instructions are provided with each replacement
sensor.
D. Cleaning Sensors
1. Conductivity/TDS/Resistivity
The conductivity cell cup should be kept as clean as possible. Flushing
with clean water following use will prevent buildup on electrodes.
However, if very dirty samples — particularly scaling types — are
allowed to dry in the cell cup, a lm will form. This lm reduces accuracy.
When there are visible lms of oil, dirt, or scale in the cell cup or on the
electrodes, use isopropyl alcohol or a foaming non-abrasive household
cleaner. Rinse out the cleaner and your Ultrameter II is again ready for
accurate measurements.
2. pH/ORP (6P)
The unique pH/ORP sensor in your Ultrameter II is a nonrellable
combination type that features a porous liquid junction.
32
It should not be
allowed to dry out.
pH/ORP SENSOR
Top View
ORP
Electrode
pH Glass
Electrode
Sensor
Body
Reference
Junction
under Glass
pH Bulb
be rejuvenated by rst cleaning the sensor well with Isopropyl alcohol
or a liquid spray cleaner such as Windex™ or Fantastic™ and rinsing
well. Do not scrub or wipe the pH/ORP sensor.
Then use one of the following methods:
1. Pour a HOT salt solution ~60°C/140°F, preferably potassium
chloride (KCI) solution (Myron L pH/ORP Sensor Storage
Solution) — HOT tap water with table salt (NaCl) will work ne
— in the sensor well and allow to cool. Retest.
or
2. Pour DI water in the sensor well and allow to stand for no more
than 4 hours (longer can deplete the reference solution
and damage the glass bulb). Retest.
If neither method is successful, the sensor must be replaced.
“Drifting” can be caused by a lm on the pH sensor bulb and/or reference.
Use isopropyl alcohol (IPA) or spray a liquid cleaner such as Windex™
or Fantastic™ into the sensor well to clean it. The sensor bulb is very
thin and delicate. Do not scrub or wipe the pH/ORP sensor.
However, if this occurs, the sensor may sometimes
Leaving high pH (alkaline) solutions in contact with the pH sensor for
long periods of time is harmful and will cause damage. Rinsing such
liquids from the pH/ORP sensor well and relling it with Myron L Storage
Solution, a saturated KCl solution, pH 4 buffer, or a saturated solution of
table salt and tap water, will extend the useful life.
Samples containing chlorine, sulfur, or ammonia can “poison” any pH
electrode. If it is necessary to measure the pH of any such sample,
thoroughly rinse the sensor well with clean water immediately after
taking the measurement. Any sample element that reduces (adds an
electron to) silver, such as cyanide, will attack the reference electrode.
Replacement sensors are available only from the Myron L Company or
its authorized distributors.
33
XVIII. TROUBLESHOOTING CHART
SymptomPossible Cause
No display, even though
measurement key pressed
Inaccurate pH readings
(6P)
No response to pH changes
(6P)
Will not adjust down to pH 7
(6P)
Battery weak or not connected.
1. pH calibration needed.
Ref. pH Cal., pg. 17.
2. Cross-contamination from residual
pH buffers or samples in sensor
well.
3. Calibration with expired pH buffers.
Sensor bulb is cracked or an
electromechanical short caused by
an internal crack.
pH/ORP sensor has lost KCl.
pH readings drift or respond
slowly to changes in
buffers/samples
or
“FAC” is displayed
repeatedly (6P)
Unstable
Conductivity/TDS/
Resistivity readings
Unable to calibrate
Conductivity/TDS
Resistivity readings much
lower than expected
1. Temporary condition due to
“memory” of solution in pH
sensor well for long periods.
Sensors, pg. 32) and recalibrate. If no
improvement, replace pH/ORP sensor
(ref. Replacement pH/ORP Sensor, pg. 37).
Clean and rejuvenate sensor (ref. Cleaning
Sensors, pg. 32) and recalibrate. If no
improvement, replace pH/ORP sensor
(ref. Replacement pH/ORP Sensor, pg. 37).
1. Clean cell cup and electrodes.
Ref. Cleaning Sensors, pg. 32.
2. Minimize test sample exposure to air.
Ref. Measuring Resistivity, pg. 10.
Clean cell cup and electrodes.
Ref. Cleaning Sensors, pg. 32.
1. Rinse cell cup more thoroughly before
measurement. Ensure pH cap is snugly
in place.
2. See Measuring Resistivity, pg. 10.
35
XIX. ACCESSORIES
A. Conductivity/TDS Standard Solutions
Your Ultrameter II has been factory calibrated with the appropriate
Myron L Company NIST traceable KCl, NaCl, and our own 442™
standard solutions. Most Myron L conductivity standard solution bottles
show three values referenced at 25°C: Conductivity in microsiemens/
micromhos, the ppm/TDS equivalents (based on our 442 Natural
Water™) and NaCl standards. All standards are within ±1.0% of reference
solutions.
1. Potassium Chloride (KCl)
The concentrations of these reference solutions are calculated from
data in the International Critical Tables, Vol. 6. The 7000 µS is the
recommended standard.
2. 442 Natural Water™
442 Natural Water Standard Solutions are based on the following salt
proportions: 40% sodium sulfate, 40% sodium bicarbonate, and 20%
sodium chloride, which represent the three predominant components
(anions) in freshwater. This salt ratio has conductivity characteristics
approximating fresh natural waters and was developed by the Myron L
Company over four decades ago. It is used around the world for
measuring both conductivity and TDS in drinking water, ground water,
lakes, streams, etc. 3000 ppm is the recommended standard.
Available in 2 oz., quarts/liters, and gallon/~3.8 liter bottles.
Order KCL-7000
Order 442-3000
3. Sodium Chloride (NaCl)
This is especially useful in sea water mix applications, as sodium chloride
is the major salt component. Most Myron L standard solution labels show
the ppm NaCl equivalent to the conductivity and to ppm 442 values. The
14.0 mS is the recommended standard.
B. pH Buffer Solutions (6P)
pH buffers are available in pH values of 4, 7 and 10. Myron L Company
buffer solutions are traceable to NIST certied pH references and are
color-coded for instant identication. They are also mold inhibited and
accurate to within ±0.01 pH units @ 25°C. Order 4, 7 or 10 Buffer.
Order NACL-14.0
Available in 2 oz., quarts/liters, and gallon/~3.8 liter bottles.
C. pH Sensor Storage Solution (6P)
Myron L pH Sensor Storage Solution prolongs the life of the pH sensor.
Available in 2 oz., quarts/liters, and gallon/~3.8 liter bottles.
36
D. Soft Protective Carry Cases
Padded Nylon carrying case features a belt clip for hands-free mobility.
Two colors to choose from;
Blue - Model #: UCC
Desert Tan - Model #: UCCDT
E. Hard Protective Carry Cases
Large case with 2 oz. bottles of calibration standard solutions (KCl-7000,
pH/ORP sensor is gel lled and features a unique porous liquid junction.
It is user-replaceable and comes with easy to follow instructions.
Model #: UPP
Model #: RPR
G. uDock™ IR Data Port Accessory Package
This accessory allows the operator to download the Ultrameter II
memory stack to a spreadsheet on a computer. The package includes a
uDock, software CD, and installation and operating instructions.
Model #: U2CIP
XX. TEMPERATURE COMPENSATION (Tempco)
of Aqueous Solutions
Electrical conductivity indicates solution concentration and ionization
of the dissolved material. Since temperature greatly affects ionization,
conductivity measurements are temperature dependent and are
normally corrected to read what they would be at 25°C.
A. Standardized to 25°C
Conductivity is measured with great accuracy in the Ultrameter II using a
method that ignores ll level, electrolysis, electrode characteristics, etc.,
and features a microprocessor to perform temperature compensation. In
simpler instruments, conductivity values are usually assigned an average
correction similar to that of KCl solutions for correction to 25°C. The
correction to an equivalent KCl solution is a standard set by chemists
that standardizes the measurements and allows calibration with precise
KCl solutions. In the Ultrameter II, this correction can be set to other
solutions or tailored for special measurements or applications.
B. Tempco Variation
Most conductivity instruments use an approximation of the temperature
characteristics of solutions, perhaps even assuming a constant value.
The value for KCl is often quoted simply as 2%/°C. In fact, KCl tempco
37
varies with concentration and temperature in a non-linear fashion. Other
Chart 1
0 5 10 15 20 25 30 35 40 45 50 55 60
1.500%
1.600%
1.700%
1.800%
1.900%
2.000%
2.100%
2.200%
2.300%
2.400%
2.500%
KCl % / °C
% / °C
Temperature
solutions have more variation still. The Ultrameter II uses corrections
that change with concentration and temperature instead of single
average values. See Chart 1.
C. An Example of 2 different solution selections and the
resulting compensation
How much error results from treating natural water as if it were KCl at
15°C?
A tap water solution should be compensated as 442 with a tempco of
1.68 %/°C, where the KCl value used would be 1.90 %/°C.
Suppose a measurement at 15°C/59°F is 900 microsiemens of true
uncompensated conductivity.
Using a 442 correction of 10 (degrees below 25) x 1.68% indicates the
solution is reading 16.8% low. For correction, dividing by (.832) yields
1082 microsiemens as a compensated reading.
A KCl correction of 10 (degrees below 25) x 1.9% indicates the solution
is reading 19% low. Dividing by (.81) yields 1111 microsiemens for a
compensated reading. The difference is 29 out of 1082 = 2.7%.
38
D. A Chart of Comparative Error
7%
Chart 2
55
(1)%
(2)%
0%
1%
2%
3%
4%
5%
6%
051015 20
25
30 35 40 45 50
Temperature
NaCl error with KCl tempco
442 error with KCl tempco
In the range of 1000 µS, the error using KCl on a solution that should be
compensated as NaCl or as 442, is illustrated in the graph below.
Users wanting to measure natural water based solutions to 1% would
have to alter the internal compensation to the more suitable preloaded
“442” values or stay close to 25°C. Users who have standardized to KClbased compensation may want to stick with it, regardless of increasing
error as you get further from 25°C. The Ultrameter II will provide the
repeatability and convertibility of data necessary for relative values for
process control.
E. Other Solutions
A salt solution like sea water or liquid fertilizer acts like NaCl. An internal
correction for NaCl can be selected for greatest accuracy with such
solutions. Many solutions are not at all similar to KCl, NaCl or 442. A
sugar solution, or a silicate, or a calcium salt at a high or low temperature
may require a “User” value peculiar to the application to provide readings
close to the true compensated conductivity.
Clearly, the solution characteristics should be chosen to truly represent
the actual water under test for rated accuracy of ±1%. Many industrial
applications have historically used relative measurements seeking a
39
number to indicate a certain setpoint or minimum concentration or trend.
The Ultrameter II gives the user the capability to collect data in “KCl
conductivity units” to compare to older published data, in terms of NaCl
or 442, or as appropriate. The Ultrameter II can be used to reconcile
data taken with other compensation assumptions, especially with its
ability to allow custom characteristics through the USER mode.
XXI. CONDUCTIVITY CONVERSION to TOTAL
DISSOLVED SOLIDS (TDS)
Electrical conductivity indicates solution concentration and ionization
of the dissolved material. Since temperature greatly affects ionization,
conductivity measurements are temperature dependent and are
normally corrected to read what they would be at 25°C (ref. Temperature
Compensation, pg. 37).
A. How it’s Done
Once the effect of temperature is removed, the compensated conductivity
is a function of the concentration (TDS). Temperature compensation of
the conductivity of a solution is performed automatically by the internal
processor with data derived from chemical tables. Any dissolved salt at
a known temperature has a known ratio of conductivity to concentration.
Tables of conversion ratios referenced to 25°C have been published by
chemists for decades.
B. Solution Characteristics
Real world applications have to measure a wide range of materials and
mixtures of electrolyte solutions. To address this problem, industrial
users commonly use the characteristics of a standard material as a
model for their solution, such as KCl, which is favored by chemists for
its stability.
Users dealing with sea water, etc., use NaCl as the model for their
concentration calculations. Users dealing with freshwater work with
mixtures including sulfates, carbonates and chlorides, the three
predominant components (anions) in freshwater that the Myron L
Company calls “natural water”. These are modeled in a mixture called
“442™” which the Myron L Company markets for use as a calibration
standard, as it does standard KCl and NaCl solutions.
The Ultrameter II contains algorithms for these 3 most commonly
referenced compounds. The solution type in use is displayed on
the left. Besides KCl, NaCl, and 442, there is the “USER” choice.
The benet of USER is that one may enter the temperature
compensation and TDS ratio by hand, greatly increasing accuracy of
40
readings for a specic solution. That value remains a constant for
all measurements, and should be reset for different dilutions or
temperatures.
C. When does it make a lot of difference?
First, the accuracy of temperature compensation to 25°C determines the
accuracy of any TDS conversion. Assume we have industrial process
water to be pretreated by RO. Assume it is 45°C and reads 1500 µS
uncompensated.
1. If NaCl compensation is used, an instrument would report 1035
µS compensated, which corresponds to 510 ppm NaCl.
2. If 442 compensation is used, an instrument would report 1024
µS compensated, which corresponds to 713 ppm 442.
The difference in values is 40%.
In spite of such large error, some users will continue to take data in
the NaCl mode because their previous data gathering and process
monitoring was done with an older NaCl referenced device.
Selecting the correct Solution Type on the Ultrameter II will allow the
user to attain true TDS readings that correspond to evaporated weight.
If none of the 3 standard solutions apply, the User mode must be used.
Temperature Compensation (Tempco) and TDS Derivation below, details
the USER mode.
XXII. TEMPERATURE COMPENSATION (Tempco)
and TDS DERIVATION
The Ultrameter II contains internal algorithms for characteristics of the
3 most commonly referenced compounds. The solution type in use is
displayed on the left. Besides KCl, NaCl, and 442, there is the “USER”
choice. The benet of USER mode is that one may enter the tempco and
TDS conversion values of a unique solution via the keypad.
A. Conductivity Characteristics
When taking conductivity measurements, the Solution Selection
determines the characteristic assumed as the instrument reports what a
measured conductivity would be if it were at 25°C. The characteristic is
represented by the tempco, expressed in %/°C. If a solution of 100 µS
at 25°C increases to 122 µS at 35°C, then a 22% increase has occurred
41
over this change of 10°C. The solution is then said to have a tempco of
2.2 %/°C.
Tempco always varies among solutions because it is dependent on their
individual ionization activity, temperature and concentration. This is why
the Ultrameter II features mathematically generated models for known
salt characteristics that also vary with concentration and temperature.
B. Finding the Tempco of an Unknown Solution
One may need to measure compensated conductivity of some solution
unlike any of the 3 standard salts. In order to enter a custom xed
tempco for a limited measurement range, enter a specic value through
the “USER” function. The tempco can be determined by 2 different
methods:
1. Heat or cool a sample of the solution to 25°C, and measure its
conductivity. Heat or cool the solution to a typical temperature
where it is normally measured. After selecting USER function,
set the tempco to 0 %/°C as in Disabling Temperature
Compensation, pg. 13 (No compensation). Measure the new
conductivity and the new temperature. Divide the % decrease
or increase by the 25°C value. Divide that difference by the
temperature difference.
2. Heat or cool a sample of the solution to 25°C, and measure its
conductivity. Change the temperature to a typical measuring
temperature. Set the tempco to an expected value as in User
Programmable Temperature Compensation, pg. 12. See if the
compensated value is the same as the 25°C value. If not, raise
or lower the tempco and measure again until the 25°C value is
read.
C. Finding the TDS Ratio of an Unknown Solution
Once the effect of temperature is removed, the compensated
conductivity is a function of the concentration (TDS). There is a ratio
of TDS to compensated conductivity for any solution, which varies with
concentration. The ratio is set during calibration in USER mode as in
section User Programmable Conductivity to TDS Ratio, pg. 13. A truly
unknown solution has to have its TDS determined by evaporation and
weighing. Then the solution whose TDS is now known can be measured
for conductivity and the ratio calculated. Next time the same solution is
to be measured, the ratio is known.
42
XXIII. pH and ORP (6P)
A. pH (6P)
1. pH as an Indicator (6P)
pH is the measurement of Acidity or Alkalinity of an aqueous solution. It
is also stated as the Hydrogen Ion activity of a solution. pH measures
the effective, not the total, acidity of a solution.
A 4% solution of acetic acid (pH 4, vinegar) can be quite palatable, but
a 4% solution of sulfuric acid (pH 0) is a violent poison. pH provides the
needed quantitative information by expressing the degree of activity of
an acid or base.
In a solution of one known component, pH will indicate concentration
indirectly. However, very dilute solutions may be very slow reading, just
because the very few ions take time to accumulate.
2. pH Units (6P)
The acidity or alkalinity of a solution is a measurement of the relative
availabilities of hydrogen (H+) and hydroxide (OH-) ions. An increase
in (H+) ions increases acidity, while an increase in (OH-) ions increases
alkalinity. The total concentration of ions is xed as a characteristic
of water, and balance would be 10
-
7
mol/liter (H+) and (OH-) ions in a
neutral solution (where pH sensors give 0 voltage).
pH is dened as the negative logarithm of hydrogen ion concentration.
Where (H+) concentration falls below 10-7, solutions are less acidic than
neutral, and therefore are alkaline. A concentration of 10-9 mol/liter of
(H+) would have 100 times less (H+) ions than (OH-) ions and be called
an alkaline solution of pH 9.
3. The pH Sensor (6P)
The active part of the pH sensor is a thin glass surface that is selectively
receptive to hydrogen ions. Available hydrogen ions in a solution will
accumulate on this surface and a charge will build up across the glass
interface. The voltage can be measured with a very high impedance
voltmeter circuit; the dilemma is to connect the voltmeter to solution on
each side.
The glass surface encloses a captured solution of potassium chloride
holding an electrode of silver wire coated with silver chloride. This is
the most inert connection possible from a metal to an electrolyte. It can
still produce an offset voltage, but using the same materials to connect
to the solution on the other side of the membrane causes the 2 equal
offsets to cancel.
43
The problem is, on the other side of the membrane is an unknown test
Glass surface
Figure 33
KCl solution
Electrode wire
Electrode
wire
H
+
ions
Junction
Plug
KCl solution
Figure 34
Junction plug
Platinum button
H+ ions
Electrode wires
Glass
Glass
Surface
solution, not potassium chloride. The outside electrode, also called
the Reference Junction, is of the same construction with a porous
plug in place of a glass barrier to
allow the junction uid to contact
the test solution without signicant
migration of liquids through the plug
material. Figure 33 shows a typical
2 component pair. Migration does
occur, and this limits the lifetime
of a pH junction, from depletion of
solution inside the reference junction
or from contamination. The junction
may be damaged if dried out
because insoluble crystals may form
in a layer, obstructing contact with
test solutions. See pH/ORP, pg. 43.
4. The Myron L Integral pH Sensor (6P)
The sensor in the Ultrameter II
(see Figure 34) is a single
construction in an easily
replaceable package. The sensor
body holds an oversize solution
supply for long life. The reference
junction “wick” is porous to provide
a very stable, low permeable
interface, and is located under the
glass pH sensing electrode. This
construction combines all the best
features of any pH sensor known.
5. Sources of Error (6P)
The basics are presented in
pH/ORP, pg. 43.
a. Reference Junction
The most common sensor problem will be a clogged junction because a
sensor was allowed to dry out. The symptom is a drift in the “zero” setting
at 7 pH. This is why the Ultrameter II does not allow more than 1 pH unit
of offset during calibration. At that point the junction is unreliable.
b. Sensitivity Problems
Sensitivity is the receptiveness of the glass surface. A lm on the surface
can diminish sensitivity and cause a long response time.
44
c. Temperature Compensation
pH sensor glass changes its sensitivity slightly with temperature, so the
further from pH 7 one is, the more effect will be seen. A pH of 11 at
40°C would be off by 0.2 units. The Ultrameter II senses the sensor well
temperature and compensates the reading.
B. ORP/Oxidation-Reduction Potential/REDOX (6P)
1. ORP as an Indicator (6P)
ORP is the measurement of the ratio of oxidizing activity to reducing
activity in a solution. It is the potential of a solution to give up electrons
(oxidize other things) or gain electrons (reduce).
Like acidity and alkalinity, the increase of one is at the expense of the
other, so a single voltage is called the Oxidation-Reduction Potential,
with a positive voltage showing, a solution wants to steal electrons
(oxidizing agent). For instance, chlorinated water will show a positive
ORP value.
2. ORP Units (6P)
ORP is measured in millivolts, with no correction for solution
temperature. Like pH, it is not a measurement of concentration directly,
but of activity level. In a solution of only one active component, ORP
indicates concentration. Also, as with pH, a very dilute solution will take
time to accumulate a readable charge.
3. The ORP Sensor (6P)
An ORP sensor uses a small platinum surface to accumulate charge
without reacting chemically. That charge is measured relative to the
solution, so the solution “ground” voltage comes from a reference
junction - same as the pH sensor uses.
4. The Myron L ORP Sensor (6P)
Figure 34, pg. 44, shows the platinum button in a glass sleeve. The
same reference is used for both the pH and the ORP sensors. Both
pH and ORP will indicate 0 for a neutral solution. Calibration at zero
compensates for error in the reference junction.
A zero calibration solution for ORP is not practical, so the Ultrameter II
uses the offset value determined during calibration to 7 in pH calibration
(pH 7 = 0 mV). Sensitivity of the ORP surface is xed, so there is no gain
adjustment either.
5. Sources of Error (6P)
The basics are presented in pH/ORP, pg. 43, because sources of error
45
are much the same as for pH. The junction side is the same, and though
Figure 35
the platinum surface will not break like the glass pH surface, its protective
glass sleeve can be broken. A surface lm will slow the response time
and diminish sensitivity. It can be cleaned off with detergent or acid, as
with the pH glass.
XXIV. SOFTWARE VERSION
Contact the Myron L Company to see if a software upgrade is available.
1. Press key.
2. Press key until three numbers are displayed as shown
in Figure 35.
3. Press key, instrument
will time out in ~15 seconds.
46
XXV. GLOSSARY
Anions Negatively charged ions.
See Solution Characteristics, pg. 40.
AlgorithmA procedure for solving a mathematical problem.See Temperature Compensation and TDS Derivation,
pg. 41.
Logarithm An arithmetic function. See pH Units, pg. 43.
ORP Oxidation-Reduction Potential or REDOX, See ORP/
Oxidation-Reduction Potential/REDOX, pg. 45.
TDSTotal Dissolved Solids or the Total Conductive Ions
in a solution. See Conductivity Conversion to TDS,
pg. 40.
TempcoTemperature Compensation See Temperature Compensation, pg. 37.
USERA mode of operation that allows the instrument user
(operator) to set a tempco and/or a TDS factor for
their specic solution type. See Temperature
Compensation, pg. 37 and Temperature
Compensation (Tempco) and TDS Derivation, pg. 41.
For details on specic areas of interest refer to the Table of Contents.
47
XXVI. ADDENDUM
48
XXVII. NOTES
49
MYRON L COMPANY
2450 Impala Drive
Carlsbad, CA 92010-7226
USA
Tel: +1-760-438-2021
Fax: +1-760-931-9189
E-Mail: info@myronl.com
techquestions@myronl.com
www.myronl.com
Made In USA
UMIIOM 06JA10
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