TECHPRO ™ Operation Manual MODELS TPH1, TP1 & TH1 06 January 10
Instrument Illustration Reference Junction (under Glass Bulb) pH Sensor (User replaceable) Conductivity Cell (Built-in Electrodes) pH Glass Electrode pH Sensor Protective Cap Temperature Sensor Preprogrammed conductivity/ TDS ratios Displayed here: • Temperature readout • Memory Storage Location • pH Calibration mS - millisiemens/cm (millimhos/cm) °C °F COND BUFFER pH TDS PPM - parts per million Conductivity TDS PPT - parts per thousand TDS/Salinity Icons for pH, Conductivity or Total Dissolv
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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.
II. FEATURES and SPECIFICATIONS A. Features • Ranges: Conductivity/ TDS — 0-20,000 µS/ppm (TPH1 & TP1) pH — 0 -14 (TPH1 & TH1) • Superior resolution four (4) digit LCD • Conductivity/TDS accuracy of ±1% of reading • pH accuracy of ± .
C. Specification Chart pH (TPH1 & TH1) 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 Auto Temperature Compensation 0-71°C 32-160°F 0-71°C 32-160°F Conductivity or TDS Ratios ±0.1°C/F KCl, NaCl, or 442™ D.
TABLE OF CONTENTS Instrument Illustration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . i I. INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 II. FEATURES and SPECIFICATIONS . . . . . . . . . . . . . . . . . . . . . 2 A. Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 B. General Specifications . . . . . . . . . . . . . . . . . . . . . . 2 C. Specification Chart . . . . . . . . . . . . . . . . . . . . .
IX. MEMORY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A. Memory Storage . . . . . . . . . . . . . . . . . . . . . . . . . B. Memory Recall . . . . . . . . . . . . . . . . . . . . . . . . . . . C. Clearing a Record/Memory Clear . . . . . . . . . . . . X. TEMPERATURE FORMAT “Centigrade & Fahrenheit” . . . . . XI. TEMPERATURE COMPENSATION (TC) DISABLE (TPH1 & TP1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . XII. SALINITY UNITS (TPH1 & TP1) .
III. RULES of OPERATION A. Operation Using the instrument is simple: • Individual or multiple parameter readings may be obtained by filling individual sensors or entire cell cup area. • Rinse the conductivity cell or pH sensor well (TPH1 &TH1) with test solution 3 times and refill. 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.
A press of b. TDS Key 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 & TH1) Measurements are made on the solution contained in the pH sensor well (ref. pH Measurement, pg. 29).
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 films, 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 & TH1) The sensor well must be kept wet with a solution.
6. IMPORTANT: After use, fill 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.
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. 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. VII. CALIBRATION A.
To bypass a calibration step, simply press value as is. to accept the present 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.
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.
will flash, 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.
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. Refill sensor well again with same buffer solution. 5. Press or 6. Press to accept 2nd point of calibration. Now the display until display agrees with buffer value. indicates the next type of buffer to be used. Single point Gain Calibration is complete.
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 & TH1) 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.
A. Memory Storage 1. While displaying a measurement, press 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. to record the MEMORY KCl °C COND Figure 6 B. Memory Recall 1. Press any measurement key. 2. Press , “MEMORY” will appear, and the display will show the last record stored. 3.
3. Fill pH 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 MEMORY , scroll down. “CLr ALL” will be displayed (see Figure 7). . All records will be cleared. Figure 7 7. Press X. TEMPERATURE FORMAT “Centigrade & Fahrenheit” 1. Press any measurement key. 2. Press repeatedly until either “C” or “F” is displayed. (see Figures 8 and 9).
1. Press . 2. Press repeatedly until “tc On” is displayed (see Figures 10 and 11). 3. Press ; the display will change to “tc OFF”. 4. Press ; all conductivity and TDS measurements are now uncompensated. Repeat steps 1-4 to reverse selection back to “tc On”. Figure 10 XII. Figure 11 SALINITY UNITS (TPH1 & TP1) “Salinity” Units may be selected in either COND or TDS mode, and in ANY solution KCl, NaCl & 442. TDS 442 shown below, (ref. Solution Selection, pg. 9).
Note: 2. Choice will determine whether the units are displayed in mS or PPT. COND = mS or TDS = PPT. Press 442 repeatedly until TDS “SALt OFF” is displayed (see Figure 12). 3. Press . The display will change from SALt OFF to “SALt On” (see Figure 13). 4. Press Figure 12 . All COND or 442 PPT TDS Figure 13 TDS readings, as selected, are now displayed in Salinity units. Either COND/mS units or TDS/PPT units are now selected.
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 (TPH1 & TH1) may fracture if the TechPro II temperature is allowed to go below 0°C/32°F. Care should be exercised not to exceed rated operating temperature. Leaving the TechPro II in a vehicle or storage shed on a hot day can easily subject the instrument to over 66°C/150°F.
2. or chloride (KCI) solution (Myron L pH Sensor Storage Solution)— HOT tap water with table salt (NaCl) will work fine — in the sensor well and allow to cool. Retest. 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 film on the pH sensor bulb and/or reference junction.
XV. TROUBLESHOOTING CHART Symptom Possible Cause No display, even though measurement key pressed Battery weak or not connected Inaccurate pH readings 1. pH calibration needed (ref. pH Cal, pg. 12). 2. Cross-contamination from residual pH (TPH1) buffers or samples in sensor well. 3. Calibration with expired pH buffers. No response to pH changes (TPH1) Sensor bulb is cracked or there is an electromechanical short caused by an internal crack. Will not adjust down to pH 7 (TPH1) pH sensor has lost KCl.
Corrective Action Check connections or replace battery (ref. Battery Replacement, pg. 20). 1. Recalibrate instrument. 2. Thoroughly rinse sensor well. 3. Recalibrate using fresh buffers (ref. pH Buffer Solutions, pg. 24). Replace pH sensor (ref. pH Sensor Replacement, pg. 20). Clean and rejuvenate sensor (ref. Cleaning Sensors, pg. 20) and recalibrate. If no improvement, replace pH sensor (ref. pH Sensor Replacement, pg. 20). Clean and rejuvenate sensor (ref. Cleaning Sensors, pg. 20) and recalibrate.
XVI. ACCESSORIES A. Conductivity/TDS Standard Solutions (TPH1 & TP1) Your TechPro 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. Available in 2 oz.
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, 442-3000, 4, 7, & 10 pH buffers and pH storage solution) - Model #: PKUU Small case (no calibration Standard Solutions) - Model #: UPP F.
2.500% 2.400% 2.300% 2.200% 2.100% % / °C 2.000% 1.900% 1.800% KCl % / °C 1.700% 1.600% 1.500% Temperature 0 5 10 15 20 25 30 35 40 45 50 55 60 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.
7% 442 error with KCl tempco 6% NaCl error with KCl tempco 5% 4% 3% 2% 1% 0% (1)% (2)% Temperature 0 5 10 15 20 25 30 35 40 45 50 55 Chart 2 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.
XVIII. CONDUCTIVITY CONVERSION to TOTAL DISSOLVED SOLIDS (TDS) (TPH1 & TP1) 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. 25). A. How it’s Done Once the effect of temperature is removed, the compensated conductivity is a function of the concentration (TDS).
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.
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. B.
Figure 15 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. (ref. pH, pg. 20). Glass surface Junction Plug H+ ions Electrode wire KCl solution D.
XXI. SOFTWARE VERSION Contact the Myron L Company to see if a software upgrade is available. 1. Press any measurement key. 2. Press key until three numbers are displayed as shown in Figure 17. 3. Press any measurement key, instrument will time out in ~20 seconds.
XXII. GLOSSARY Anions Negatively charged ions. See Solution Characteristics, pg. 28. Algorithm A procedure for solving a mathematical problem. See Temperature Compensation and TDS Derivation, pg. 28. Logarithm An arithmetic function. See pH Units, pg. 30. TDS Total Dissolved Solids or the Total Conductive Ions in a solution. See Conductivity Conversion to TDS, pg. 28. Tempco Temperature Compensation See Temperature Compensation, pg. 25.
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