Extech PH220-S User`s Manual
Contents
1. is expressed or implied T Support line 781 890 7440 Technical support Extension 200 E mail support extech com Repair amp Returns Extension 210 E mail repair extech com Product specifications subject to change without notice For the latest version of this User s Guide Software updates and other up to the minute product information visit our website www extech com Extech Instruments Corporation 285 Bear Hill Rd Waltham MA 02451 Copyright 2005 Extech Instruments Corporation All rights reserved including the right of reproduction in whole or in part in any form 8 Model PH220 Version 2 0 4 052. User s Guide EXTECH INSTRUMENTS Waterproof Palm pH Meter Model PH220 INSTRUMENTS GS g0 C PH mV Temp Waterproof TIE nl SC PH220 Introduction Congratulations on your purchase of the Extech PH220 waterproof pH mV meter This microprocessor based device with tactile buttons is battery operated and ideal for field use The PH220 simultaneously displays pH or ORP mV and temperature The rubber holster which protects the meter has a magnetic backing for convenient mounting Careful use of this meter will provide years of reliable service Specifications mV ORP 1999 mV DC 1 mV 2mV Temperature 32 0 to 212 0 F 0 0 to 99 9 C 0 5 F 0 3 C pH 0 00 to 14 00pH 0 01pH 0 02pH Temperature Compensation 32 to 212 F 0 100 C Automatic ATC Power 9 volt battery Display Dual LCD display for simultaneous pH or mV and temperature readings Over range or open indication Low Battery Indication Dimensions Weight 4 25 x 3 00 x 1 18 108 x 75 x 30mm 0 3 Ibs 135g Accessories supplied with kit Sample buffers and battery Stick electrode for model PH220 S Electrode with 39 cable for model PH220 C 2 Model PH220 Version 2 0 4 05 Meter Description Battery Compartment under holster Rubber Holster 1 LCD Display i 2 3 Function buttons ap ON Electrode input POLLY ttt COE Display Description Units o
3. de coating that occurs over time will determine the cleaning method Soft coatings can be removed by vigorous stirring or by using a squirt bottle Organic chemical coating hard coatings should be chemically removed Only in extreme cases should the bulb be cleaned mechanically Troubleshooting an Electrode Symptom Recommended Solution Long response time or Soak in 4 07 M Potassium Chloride KCl reading drift 60 C for 30 minutes surface 0 1 m HCL for 30 mins or as needed solids on sensor solvent and a buffer 7 00 Organic solvents are coating Organic mole fraction has to be less than sensor 50 to assure reasonable readings Limit time of measurement Keep probe in the 7 0 buffer between readings Soak electrode tip in wetting cap filled with wetting 1ml 7 00 buffer for 24 to 48 hours no wipe electrode Same readings in different Cracked or broken bulb Replace electrode Use bulb guard Avoid buffers and samples plunging electrode to bottom of container and spinning bars Wetting cap will protect bulb between tests Erratic LCD display Samples have low ionic For each 50 ml of sample add 1 drop strength lacks salt e g 50uL of SAT KCI No alteration in pH will distilled de ionized boiled occur by inert KCl lake water high pressure 7 Model PH220 Version 2 0 4 05 Calibration and Repair Services EXTECH INSTRUMENTS CORPORATION offers complete repair and calibration services for all of the products we
4. equilibrium with the buffer solution When the reading stabilizes read the pH measurement on the main display An out of range reading is indicated by three dashes The dashes will also display if the electrode is not connected to the meter When the test is complete rinse the electrode with distilled or deionized water Electrodes should always be rinsed before and between samples with distilled or deionized water to remove all traces of storage solution process medium or previous test solution Temperature Units To change the unit of measure for temperature C to F or F to C press and hold the pH mV button for 3 seconds The LCD reflects the unit of measure mV ORP Measurements PQs es Connect the ORP electrode to the meter Rinse the ORP electrode Turn the meter on Use the pH mV button to select the mV mode The display will reflect the unit of measure Place it into a sample solution When the LCD stabilizes it will read the redox potential of the sample in millivolts mV When the test is complete rinse the electrode with distilled or deionized water 5 Model PH220 Version 2 0 4 05 Temperature Compensation Because the millivolt output of a pH electrode varies with temperature the meter must compensate for the variations to obtain accurate measurements The PH220 automatically compensates for solution temperatures that stray from room temperature using the thermometer that is b
5. f Measure Measured Value Temperature Battery Life Units Automatic Temperature Compensation Solution Temperature 3 Model PH220 Version 2 0 4 05 Calibration pH electrodes are like batteries they run down with time and use Because the sensitivity of a pH electrode degrades over time it is very important to frequently calibrate the meter to the electrode Calibration is performed using standard buffer solutions at room temperature 78 F 25 C Buffer solutions are solutions of a know pH that have the useful property of resisting changes in pH These can be purchased already mixed or in capsule form and are usually available in three pH values pH 4 00 pH 7 00 and pH 10 00 Calibration is always performed using the pH 7 00 buffer first followed by a second calibration Select pH 4 buffer for the second calibration if typical measurements will be less than pH7 or use a pH 10 buffer if typical measurements will be greater than ph 7 In order to obtain the most accurate results possible a pH meter should be calibrated at least once a day 2 Point Calibration Procedure Turn the meter on 2 Use the pH mV button to select the pH mode The unit of measure appears on the LCD 3 Remove the electrode from its cap and rinse with distilled or deionized water Place the electrode in fresh pH 7 00 buffer solution and stir Allow 30 seconds for the electrode ATC to reach thermal equilibrium with the buffer
6. sell For periodic calibration NIST certification or repair on most Extech products call customer service for details on services available Extech recommends that calibration be performed on an annual basis to ensure calibration integrity Warranty EXTECH INSTRUMENTS CORPORATION warrants this instrument to be free of defects in parts and workmanship for one year from date of shipment a six month limited warranty applies to sensors and cables If it should become necessary to return the instrument for service during or beyond the warranty period contact the Customer Service Department at 781 890 7440 ext 210 for authorization or visit our website www extech com for contact information A Return Authorization RA number must be issued before any product is returned to Extech The sender is responsible for shipping charges freight insurance and proper packaging to prevent damage in transit This warranty does not apply to defects resulting from action of the user such as misuse improper wiring operation outside of specification improper maintenance or repair or unauthorized modification Extech specifically disclaims any implied warranties or merchantability or fitness for a specific purpose and will not be liable for any direct indirect incidental or consequential damages Extech s total liability is limited to repair or replacement of the product The warranty set forth above is inclusive and no other warranty whether written or oral
7. solution 5 Press and hold the CAL key for three 3 seconds to enter the calibration mode The CAL display appears and then the pH value flashes on the LCD 6 When the pH stops flashing SA save and then END will appear in sequence Rinse the electrode with distilled or deionized water 8 Place the electrode into the second buffer pH 4 00 or pH 10 00 ands stir Allow 30 seconds for the electrode ATC to reach thermal equilibrium with the buffer solution 9 Press and hold the CAL key for three 3 seconds to re enter the calibration mode The CAL display appears and then the pH value flashes on the LCD 10 When the pH stops flashing SA save the Slope percentage and then END will appear in sequence 11 The meter is now calibrated and ready for use Note The Slope percentage is an indication of the health of the electrode Since pH electrodes vary in performance from one to the next this meter includes a feature that displays the electrode s slope in If the slope is below 75 the electrode should be replaced a slope of 100 is ideal 4 Model PH220 Version 2 0 4 05 PH Measurements Connect the pH electrode to the meter Turn the meter on Use the pH mV button to select the pH mode The unit of measure appears on the LCD Rinse the electrode with distilled or deionized water Place the electrode in the solution Allow 30 seconds for the electrode ATC to reach thermal
8. uilt in to the electrode Temperature is displayed on the lower LCD line Battery Replacement The 9V battery requires replacing when all three black bars inside the battery display icon switch off Replace the battery per the following 1 Remove the orange protective jacket holster that surrounds the meter by pulling it over the top of the meter ensure that the electrode is disconnected 2 Pull the battery compartment up from the top of the meter by the two indentations using two fingers If necessary pry the ends of the cover with a coin to release the watertight seal 3 Install a fresh 9V battery Battery polarity is indicated on the battery compartment cap 4 To reinstall the battery compartment align the notch in the cover with the grove in the meter and press 5 Reinstall the protective holster 6 Model PH220 Version 2 0 4 05 Electrode Maintenance and Troubleshooting Most pH measurement difficulties are caused by electrode problems Careful handling and proper storage of the electrode will increase measurement accuracy Electrodes should be rinsed to remove all traces of storage solution process medium or previous test solution Electrode Storage The electrode should be stored in a soaker bottle or wetting cap filled with pH4 buffer Never store an electrode in distilled or deionized water as this will cause migration of the fill solution from the electrode Electrode Cleaning The type of electro
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