615-26 User Manual
Contents
1. Industrial electrodes and replacement parts are warranted to be free from defects in material and workmanship for a period of three 3 months from the date of installation or eighteen 18 months from the date of shipment when used under normal operating conditions and in accordance with the operating limitations and maintenance procedures given in the instruction manual and when not having been subjected to accident alteration misuse or abuse Chemical solutions standards or buffers carry an out of box warranty Should they be unusable when first out of box contact IC CONTROLS immediately for replacement In the event of failure within the warranty period IC CONTROLS or its authorized dealer will at IC CONTROLS option repair or replace the product non conforming to the above warranty or will refund the purchase price of the unit The warranty described above is exclusive and in lieu of all other warranties whether statutory express or implied including but not limited to any implied warranty of merchantability or fitness for a particular purpose and all warranties arising from the course of dealing or usage of trade The buyer s sole and exclusive remedy is for repair or replacement of the non conforming product or part thereof or refund of the purchase price but in no event shall IC CONTROLS its contractors and suppliers of any tier be liable to the buyer or any person for any special indirect incidental or co2. 5to 10 9 deionized water 0 1to 2 Low Conductivity Symptoms Low conductivity effects can be traced to concentrated pH Buffer carryover into low conductivity sample differences between reference junction potential in low sample conductivity vs in high buffer conductivity differences in apparent reference junction potential as rate of flow through the pH flowcell washes ions away from the reference absorption of carbon dioxide by low conductivity sample when exposed to air for calibration and high resistance of the pure water producing a jumpy ungrounded antenna effect in the pH electrode pair The effects will become more noticeable as the conductivity falls from simply Pure to High Purity and on to Ultra Pure where below 1 micro Siemen they become predominant Also the effects become more noticeable as greater accuracy is required Buffer carryover Standardizing a pH electrode in a high conductivity buffer will increase the time required for the reading to stabilize in low conductivity sample After regular pH buffer was pumped through a general purpose pH flow cell in laboratory tests IC CONTROLS observed 3 hours of pH electrode drift before a 1 micro Siemen sample stabilized Alternatively Grab sample calibration with regular pH buffers risks pH Buffer carryover contamination of the sample The best results will occur when pH Page 4 615 26 Instructions Pure Water pH Measurement IC CONTROLS Buffers and sample are close to th
3. Troubleshooting o 15 Error and Caution Messages from 655 pH Analyzer 16 Checking The Automatic Temperature Compensator 19 Checking the Reference Electrode 19 Checking the Glass Electrode o oao a 000 19 Electronics wiring Problems o e eee ee ee 19 APPENDIX A Recommended Supplies 20 APPENDIX B Product Selection 21 Model Dima a a ro Re aoe ee Gores AA 21 Model 655 eek o ib AE Pc a ee Be ae 22 APPENDIX C Installation 0 0202 00005004 23 Checking the pH Measuring Electrode 0 0004 23 Checking the Reference 000 eee ee ee eee 23 Checking The Temperature Compensator And Preamp 23 Typical Flow Mounting s s anoa o e eo 23 Electrical Connections rua ea eA Pia A a ae aa 23 APPENDIX D PARTS LIST 0200 00055008 24 APPENDIX E DRAWINGS 020 00022 eee 25 Mounting Dimensions o 0 0 a e ae a a a a y A 25 Wining 649 2060 00 a A Sak A a Jed TI 26 Industrial Products Warranty o 27 615 26 Instructions Page 1 IC CONTROLS General Information General Information Introduction The IC CONTROLS industrial pH sensor forms an electrode pair for the detection of hydrogen ion activity with provision for special requirements imposed by continuous operatio
4. are often associated with the solution ground quality Check the solution ground is intact and of good quality less whan one ohm Testing of the analyzer pH meter is generally beyond the scope of this instruction manual however a preamp to analyzer wiring drawing is included in the drawings section for your guidance Preamplifier quality can be tested by the 659 analyzer calibrator by switching a 100 meg ohm resistor in series with the simulated electrode signal A good preamp may show a jump due to switch transients and return to the previous reading A bad preamp may pin at upscale or downscale or simply hunt replace the preamp An alternative preamp quality test is to substitute a new known good preamp and see if the problem goes away 615 26 Instructions Page 19 IC CONTROLS APPENDIX A Recommended Supplies APPENDIX A Recommended Supplies ORDER TOLL FREE 1 800 265 9161 Fax 1 519 941 8164 Part Number Description A1600053 pH calibration kit for Low Conductivity Water 1 year supply of most maintenance items Extra Low Conductivity Buffer needs depend on calibration method Two 6 packs Low Conductivity buffer 4 7 10 2 x A1100216 6P 2 x A1100217 6P 2 x A1100218 6P electrode wash solution A1100091 three 250 ml beakers A1100020 one squeeze bottle A1100014 Deionized water 6 pack A1100192 6P pH Neutral Conductivity Adjusting Solution A1100219 100mL Graduated Cylinder A1100007 1cc Syri
5. kept as short as possible to ensure minimum lag time This is particularly important in pH control applications The Model 615 26 pH sensor is designed for side sample stream service and must be installed so that the sample flow is fairly steady through the pH sensor The sensor assembly should be mounted securely to a wall pipe or post Constant flow is desireable so a sample flow adjusting valve and atmospheric drain have been included to help stabilize flow at the pH sensing surfaces Electrical Connections Electrical connections between the sensor and the transmitter can be made using six conductor shielded cable A9200007 or Belden 9536 see Dwg D5970174 ina 1 2 grounded conduit Note DO NOT run any AC power wiring in this circuit 615 26 Instructions Page 23 IC CONTROLS APPENDIX D PARTS LIST APPENDIX D PARTS LIST ORDER TOLL FREE 1 800 265 9161 Fax 1 519 941 8164 Part Number Description A2500167 pH preamp for 655 656 A7050002 Tubing 1 4 clear poly A7050009 Tubing 1 4 black tygon A7100010 Rotameter 10 100cc with ss valve A7200007 1 4 Tube Type SS Ball Valve A7200020 1 4 Tube Type SS 3 way Valve A72014514s tube insert 1 4 x 1 8 ID A7201486 SS Elbow 1 4 tube to 1 8 NPT A7401481 White PP fitting 1 4 tube to 1 8 NPT A7401486 White PP Elbow 1 4 tube to 1 8 NPT A2100006 Head Tank assembly A2100059 615 SS flowcell assembly sa
6. 00ml bottles at the on line pH sensor with the sample feed tube submerged Allow the sample to overflow the bottle for 30 minutes to flush any pH influencing traces away Dump the bottle and then add 5cc A1100219 pH Neutral Conductivity Adjusting Solution and refill with fresh sample Cap the bottles for minimum carbon dioxide exposure 2 Make a note of the normal sample flow rate Pour the 7 buffer into the calibration bottle on the 615 26 or attach the 7 buffer bottle and puncture the bottom with a tack to allow gravity flow Turn the three way valve up to gravity feed Low Conductivity 7 0 pH buffer to the pH sensor at the same flow rate that the sample is normally flowing g 4 Allow 15 to 30 minutes for the reading to stabilize it is best to start with both sensor and buffer are at the same temperature Be careful not to introduce air Installing Standard 615 26 Instructions Page 9 IC CONTROLS Calibration Procedure 5 When the reading is steady calibrate the on line pH meter to display the pH value of A1100217 7 pH buffer 6 Close the 3 way valve by turning it halfway to stop the flow Replace the 7 buffer with 500 ml of the sample collected in step 1 then reopen to rinse the tubing valve pH electrodes and flowcell Be careful not to introduce air Then pour the second buffer 500 ml of A1100216 low conductivity 4 1 pH buffer for samples with pH less than 7 or A1100218 10 2 pH buffer for samples higher than 7 in
7. 100220 6P pH Buffer mixed 6 PAK Low Cond A7400031 10cc Syringe A1100020 Beakers set of 3 250 ml A1601158 Ultra Pure pH Lab Cal Kit air exclusion flow beaker type incl research grade pH electrode Page 6 615 26 Instructions Calibration Procedure IC CONTROLS Calibration Procedure The sensor can simply be installed and used as shipped and readings with an accuracy of 1 0 pH will typically be obtained In Low Conductivity Waters the pH will likely show an offset due to the flow of water sweeping the reference ions away IC CONTROLS recommends GRAB SAMPLE CALIBRATION with constant flow rate to deal with this phenomena Grab Sample Calibration with Ultra Pure water itself presents a problem since drawing an pure sample through the air into a beaker will dissolve carbon dioxide from the air and can produce an acidic error often of 1 pH unit or more However since the 615 25 is normally operated above 1 micro Siemen Conductivity this may not be much problem See RECOMMENDED SUPPLIES P N A1601158 for an air exclusion beaker and pure water pH laboratory electrode set for ideal grab sample calibration Ultra Pure Grab Sample Calibration Note Either of the grab methods depend for accuracy on the Grab Sample electrode analyzer set being accurately buffered before use pH Calibration Kit for Low Conductivity Waters A1600053 should be used Place the sensor on stream with the transmitter measuring pH Wait 30 to 60 minutes for the r
8. ENDED CABLE BELDEN 9537 AVAILABLE FROM IC CONTROLS AS PN A9200008 appl 615 26 34 A ANALYZER SHIPPED WITH 1 07K DUMMY T C REMOVE IF pH SENSOR HAS INTERNAL Te 2300167 ULTRA PURE pH SENSOR used in code AwO A ENSURE THERE IS NO CONNECTION BETWEEN REFERENCE AND ELECTRICAL GROUND al 9 EN 2 0 600 lt 655 T gt SHOULD BE 20 MEGS OR HIGHER SHORT WILL PRODUCE GROUND LOOP ERROR scale sheet of IG CONTROLS un oc Gace feces aa 29 Centennial Road Orangeville Ontario LOW 1R1 Canada Tel 519 941 8161 Fax 519 941 8164 Industrial Products Warranty Industrial instruments are warranted to be free from defects in material and workmanship for a period of twelve 12 months from the date of installation or eighteen 18 months from the date of shipment from IC CONTROLS whichever is earlier when used under normal operating conditions and in accordance with the operating limitations and maintenance procedures in the instruction manual and when not having been subjected to accident alteration misuse or abuse This warranty is also conditioned upon calibration and consumable items electrodes and all solutions being stored at temperatures between 40 F and 110 F 5 C and 45 C in a non corrosive atmosphere IC CONTROLS consumables or approved reagents must be used or performance warranty is void Accessories not manufactured by IC CONTROLS are subject to the manufacturer s warranty terms and conditions Limitations and exclusions
9. INSTRUCTION MANUAL MODEL 615 26 Ultra Pure Water pH SENSOR for 1 to 0 055 microsiemens cm Conductivity or 1 to 18 megohm cm Resistivity CONTROLS IC CONTROLS CONTENTS um 615 26 111 General Information o e e 2 InthOGUction e a a a ea a oe ee ED Bee ex 2 pH Reaction Chemistry o oe o 2 pH Measuring Elements oston mats aa o R REN Aa a aia ai AT 3 Reference Electrodes a ee 3 pH in Low Conductivity Waters o o eee 3 Pure Water pH Measurement e e 4 Low Conductivity Samples 0 e eee ee 4 Low Conductivity Symptoms eee ee eee 4 Gaon Dioxide 2 aii rs a E a ee EY 5 Laboratory Solutions 2 o e o 5 On Line SOTONE 2 visigoda RA 6 Calibration Procedure 0 e e e 7 Ultra Pure Grab Sample Calibration a a 7 Procedure for Grab Sample Laboratory Calibration 8 Two Buffer Calibration o e ee 9 Maintenance tii ia e dn A ae an 11 Dae ec anit lr ra ee Pe E de beth ce A 11 WER e de ed dg here ae Ae aed te ead bee eed aed doe ha 11 Quarterly aia Bo thee ee a a ea es Ak 11 Annual Routine 2 e 12 Troubleshooting e 13 isolating the Problem 0 a aee mapa ee 13 Analyzer Problem Troubleshooting o e 14 pH Electrode Sensor
10. ation can be done to see if there is any problem in the analyzer alone independent of the preamp and field wiring Problem identified a If the offset is within 10 mV of zero then the analyzer is good and it is the wiring or the preamp that is the problem and will have to be replaced or re done b If the offset is greater than 10 mV from zero then the problem is in the electronics If should go back to the service shop for electronic alignment or repair A better way of testing the analyzer is to use a model 659 portable analyzer and pH calibrator and to do a two point calibration at 7 0 and 4 0 pH or at 7 0 and 10 0 pH With the 615 26 it is necessary to add a jumper from the BNC fitting to the solution ground terminal to get good stable readings This will give you the most accurate indication of the analyzer s performance and greater confidence in your installation Page 14 615 26 Instructions Troubleshooting IC CONTROLS pH Electrode Sensor Troubleshooting In order to troubleshoot a pH electrode it is very important to have no doubt that the analyzer used to get readings for troubleshooting is functioning correctly IC Controls manufactures a portable pH analyzer and pH calibrator model 659 for this purpose The calibrator can be used to prove the pH analyzer before use or it can be used to prove the pH loop analyzer where the problem has shown up NOTE Before testing your pH sensors be sure your test analyzer is k
11. calibration passed since last have passed since calibration the analyzer was calibrated CA1 9 12 months have More than 12 Verify electrode operation and or passed since months have follow the Replacing Electrodes electrodes were passed since the procedure replaced electrodes were replaced Err pH reading Process too Verify process off scale pH gt 14 caustic for accurate measurement Large electrode Service or replace electrode offset 615 26 Instructions Page 17 IC CONTROLS Troubleshooting Error Err Description pH reading off scale pH lt 0 Causes Electrode not connected Solutions Connect electrode or check connections Electrode not responding Replace filling solution in reference electrode Etch glass electrode Clean reference electrode Replace electrode Process too acidic to be measured Verify process Error Messages for Temperature Error Description Causes Solutions Err Temperature Temperature less Verify process and sensor location reading than 5 C off scale Temperature Electronic Follow procedure in Hardware less than calibration Alignment section 5 necessary Err Temperature Temperature Attach temperature compensator reading compensator not off scale attached Turn off temperature input Follow Input Temperature On Off Switch procedu
12. ctivity Waters High Purety Waters are generally those with a conductivity less than 15 micro Siemen but more than 1 micro Siemen Ultra Pure Waters are generally those with a conductivity less than 1 microSiemen or high resistivity of 1 meg ohm to 18 meg ohms at 25 C Waters with such insulating properties are prone to act like an open circuit and cause the pH electrodes to become a good antenna jumping at every little upset or passing person Great care is needed in grounding to cut interference Even friction from sample water flow can cause static buildup Also the high purity means few ions to take part in the pH electrical circuit with resultant flow sensitivity ions swept away at different rates and fast aging of the pH glass ions swept to waste are seldom replaced The 615 25 pH sensor has been designed to minimize these problems in High Purity Waters however High Purity pH measurement still requires care on the users part The 615 26 pH sensor has been designed to minimize these problems even with the more extreme conditions in Ultra Pure Waters however Ultra Pure pH measurement still requires more care on the users part 615 26 Instructions Page 3 IC CONTROLS Pure Water pH Measurement Pure Water pH Measurement Low Conductivity Samples Normally pH measurements are made in waters with 1 000 to 10 000 micro Siemen Conductivity The conductivity comes from dissolved solids typically salts plus net acid or base which explai
13. e same conductivity Reference Liquid Junction Potential A junction potential occurs when the reference electrolyte contacts the sample much like the thermocouple potential that occurs when two different metallic conductors are in contact The junction potential will vary in size with differences in composition between the electrolyte and sample Unlike metallic conductors liquids are mobile and diffuse into each other until diffusion pressure equalizes Since in an electrolyte the charge carriers are ions which have different sizes and charges which affect their ability to move through the solution concentrations of various sizes and charges may tend to separate out at the liquid junction producing a junction potential While a junction potential can be standardized out it must remain constant to fully disappear With a big concentration differences between low conductivity sample and the reference electrolyte there will be a larger junction potential and with any sample flow variation drifty pH readings are seen due to changes in the rate that ions are washed away In the laboratory steady readings can be achieved by measuring in samples and standards with conductivity similar to the reference electrolyte For on line samples constant flow rates and attention to flow path are needed to achieve steady junction potentials and readings Carbon Dioxide Since High Purity water contains little dissolved material its resistance to pH change b
14. e same normality A third reason is that the pH of solutions exhibit buffer action or resistance to pH change at various pH values These regions of resistance to pH change cause the observed pH to not change with ongoing reagent addition and then suddenly begin to change even rapidly change with the same ongoing reagent addition rate The Page 2 615 26 Instructions General Information IC CONTROLS buffer effects exhibit different pH resistance points and different pH stiffness for each chemical involved so a real world situation can be very complex and not appear to be repeatable a real can of worms so to speak Since this adds on to the logarithmic base nature of pH it can be a major challenge to control Reaction Demand Curves done for all possible extreams of chemicals is one way to unravel this can of worms pH Measuring Elements Physical and chemical properties of the process and the electrode pair are important as in a liquid ions can move anywhere without restriction A pH measuring electrode measures hydrogen ions by establishing a physical chemical balance or equilibrium between the available hydrogen ions in the process solution and attractive parking sites for hydrogen ions in the glass sensing membrane Thus if there are other ions that move in and occupy the landing sites or fast flow that upsets the chemical balance or high low temperatures that speed up or retard the equilibrium being established similar to speeding
15. eading to stabilize particularly in a hot or cold stream and the AUTO T C element to reach equilibrium When the reading is stable note its value and immediately obtain a pH sample of the effluent sample near the sensor This may be done by inserting an electrode in an air exclusion type calibration kit A1601158 which eliminates CO dissolution and acidic error attached to a portable digital analyzer such as IC Controls 659 and adjusting the two analyzers to agree Or it may be done by collecting a 500 ml bottle of sample for laboratory check With Ultra Pure Water samples the bottle should be pre cleaned then filled and allowed to continuously overflow for 30 minutes or so with the fill tube submerged to the bottom of the bottle This will rinse trace contaminants away so the pH is less affected The sample then needs pH Neutral Conductivity Adjusting Solution A1100219 added to stop CO dissolution on the way to the lab Check the sample on a lab pH meter see Proceedure for Grab Sample Laboratory Calibration below and note the true pH Subtract the smaller pH reading to obtain the offset standardize adjustment required at the process and re standardize at the instrument as necessary to obtain agreement Take more than one sample to ensure greatest accuracy Assembling the 615 sensor Solution ground hookup 615 26 Instructions Page 7 IC CONTROLS Calibration Procedure Procedure for Grab Sample Laboratory Calibration No
16. llow the sample to overflow the bottle for 20 minutes to flush any pH influencing traces away Dump the bottle and then add 5cc A1100219 pH Neutral Conductivity Adjusting Solution and refill with fresh sample Cap the bottle for return to the lab with minimum carbon dioxide exposure 2 In the laboratory pour 200 ml of A1100217 low conductivity 7 pH buffer into a 250 ml beaker Rinse the pH electrodes with A1100217 7 pH buffer over the drain Place the electrodes in the beaker of 7 pH buffer 2 4 When the reading is steady calibrate the lab meter to display the pH value of the A1100217 7 pH buffer 5 Pour 200 ml of A1100216 low conductivity 4 1 pH buffer for samples with pH less than 7 or A1100218 10 pH buffer for samples higher than 7 into a 250 ml beaker O lt Rinse the pH electrodes over the drain with the buffer used in step 5 Place the electrodes in the beaker of buffer 7 When the reading is steady calibrate the lab meter to display the pH value of the buffer used 00 aS Pour 200 ml of the sample collected in step 1 into a 250 ml beaker pour against the side to minimize CO2 pickup from the air Page 8 615 26 Instructions Calibration Procedure IC CONTROLS 9 Rinse the pH electrodes over the drain with sample Place the electrodes in the beaker of sample 10 When the reading is steady record the grab sample pH 11 Repeat steps 8 to 10 to confirm the pH value 12 Return to the process pH meter and s
17. lope is too slope flat or too steep Previous calibration is Buffers used in buF1 Select buffers which are retained and buF2 are too further apart to allow for close together or are more accurate slope the same buffer calculation Perform buF1 calibration only and use default slope Wrong buffer specified Redo calibration with correct buffer Page 16 615 26 Instructions Troubleshooting IC CONTROLS Error Description Causes Solutions E 1 5 Temperature Process outside of Use manual temperature compensator is TC operating range compensation off scale of 5 C to 105 C TC not connected Check TC connections or install TC CA1 6 Offset gt 1 3 pH Large offset in Check electrode service or units reference electrode replace if necessary or electrode depleted Bad buffer used for Use fresh buffer calibration CA1 7 Slope efficiency Poor electrode pair Check both the reference and less than 85 or performance the glass pH electrode The greater than 102 glass may need to be etched or Nernstian cleaned response Bad buffer used for Use fresh buffer calibration Buffers were too Use buffers which are further close together apart Electrodes did not Allow more time for the analyzer stabilize to stabilize repeat calibration if necessary Use buffer closest to 7 pH as first buffer CA1 8 30 days have More than 30 days Do a
18. mple inlet and outlet 1 4 tube A2300130 Gravity Calibration bottle and fittings assy 615 26 A2300131 1 4 tube flow restrictor for 615 26 head tank inlet A7201410 SS Tee 1 4 tube to 1 4 tube A7401485 White PP Branch Tee 1 4 tube 1 8 NPT A7400135 P Regulator 1 4 ports A7400118 PP 3 4 Clamp A7400119 PP 3 Clamp A7400125 PP 1 Clamp A3100229 SS 3 way valve bracket A3100230 SS regulator bracket A3100231 SS valve bracket A2101514 Surface J box and mounting without preamp A9141006 6 position terminal block Page 24 615 26 Instructions APPENDIX E DRAWINGS IC CONTROLS APPENDIX E DRAWINGS Mounting Dimensions 26 0000 24 2500 CL PREAMP INTERFACE 2 615 FLOW CELL S INLET 1 4 TUBE 4 DRAIN 3 4 MNPT 14 0000 12 2500 2 3750 H 11 7500 dote ley otr fS Che aa CONTROLS Orangeville Ontario Canada MAGE oleo UN eb DUTLINE DIMENSIONS used in W3D4A970063 REV an 615 26 Instructions Page 25 SENSOR REMOTE J BOX INSTRUMENT BNC A TB 655 T pally TB200 TB201 GLASS ON CENTRE REF ON OUTSIDE SOLN GND SHLD S TB400 Ka lt HOT gt 2 lt NEUTD 3 GND A IF SENSOR DOES NOT HAVE AUTO TC SELECT MANUAL TC AND SET VALUE USING MICROPROCESSOR loy date _ G CONTROLS A TC IS NOT POLARITY SPECIFIC lor EF C 12 2 04 Orangeville Ontario Canada chk TITLE WIRING A CUSTOMER SUPPLIED RECOMM
19. n in process environments pH is a way of expressing the apparent availability of hydrogen ions in a solution in a form that will react and is defined as the negative logarithm of hydrogen ion activity In most solutions the hydrogen ion concentration is going to be only a fraction Water for example is composed of one hydrogen ion H and one hydroxyl ion OH that reacted together to produce one water molecule H20 H OH H20 Molecules made by such reactions show some tendency to break up or dissociate into the original ions For water chemists found this break up produces 0 0000001 mole of hydrogen ions per liter of water 1 mole 1 x molecular weight For strong hydrochloric acid say 1 0 molar chemists found 1 0 mole of hydrogen ions per liter For sodium hydroxide 1 0 molar they found 0 00000000000001 mole of hydrogen ions per liter They also found it difficult to handle these cumbersome numbers and in 1909 Danish scientist Sven P L Sorensen suggested that the logarithm of the number be used Since logarithms express a number as the power to which 10 must be raised to equal that number with a fraction the power will be negative Eg 10 10 x 10 100 while 10 1 10 x 1 10 1 100 0 01 Thus the above examples become water 0 0000001 107 7 strong hydrochloric 1 0 S40 0 sodium hydroxide 00000000000001 210 14 and you get a pH scale 0 to 7 to 14 pH Reaction Chemistry Sometimes with pH reacti
20. nd Caution Messages from 655 pH Analyzer Error Description Causes Solutions E1 1 Electrode has not Poor electrode Check electrode redo stabilized after 5 performance calibration minutes of calibration Regular Buffer used Calibrate using Low remaining drops are Conductivity Buffers changing buffer value A1100216 A1100217 A1100218 Dehydrated pH Perform electrode electrode maintenance by soaking 24 hours in A1100091 pH electrode wash solution E1 2 Electrode has Large offset in electrode Calibrate specifying 4 stabilized but offset 7 10 or custom buffer gt 1 3 pH units This to allow for offsets of up error generated by to 4 pH units autodetection of 4 7 10 Perform electrode buffers only Previous maintenance offset is retained Wrong buffer used for Specify correct buffer calibration Only 4 7 10 and redo calibration pH buffers can be detected automatically E1 3 Electrode has Wrong buffer used for Redo calibration stabilized but offset gt calibration specifying correct buffer 4 pH units Previous offset retained Bad electrode Perform electrode maintenance Electrode not connected Check connections redo calibration E 1 4 Electrode efficiency less buF2 calibration done Calibrate using buF1 than 60 or greater than before buF1 for first buffer then go to 110 Nernstian calibration buF2 to calibrate for response s
21. nge A7400016 plus an instruction sheet A1601158 Ultra Pure pH Lab Calibration Kit air exclusion flow beaker type Includes Orion Ross Research Grade combo pH electrode 8172BN flow beaker assy A2102013 6 pack Low Conductivity buffer 4 7 10 2 x A1100216 2 x A1100217 2 x A1100218 pH neutral conductivity adjusting solution A1100219 1cc Shringe A7400016 instruction sheet A1100216 6P 4 1 pH Buffer 6 pack for Low Conductivity Applications A1100217 6P 7 0 pH Buffer 6 pack for Low Conductivity Applications A1100218 6P 10 pH Buffer 6 pack for Low Conductivity Applications A1100119 pH Neutral Conductivity Adjust solution A1100220 6P pH Buffer mixed 6 pack for Low Conductivity Applications 4 7 10 2 x A1100216 2 x A1100217 2 x A1100218 A1600105 Portable analyzer calibrator with LCD display complete with carrying case test electrode adapter cables three 250 ml beakers and instructions Allows full test exercising of all aspects of pH system Page 20 615 26 Instructions APPENDIX C Installation IC CONTROLS APPENDIX C Installation Since the 615 26 is supplied on a back panel installation is a matter of selecting a site for mounting that has good access for calibration and attaching the panel with 4 bolts Sample should be delivered in a 1 4 inch ss line and removed from the atmospheric drain in a 3 4 line Note Do not tube up to the 615 sensor ou
22. nown to be good FIRST Inspect electrodes and if dirty or scaled a Clean with soft cloth b Acid clean to remove scale we recommend A1100094 gentle scale remover SECOND Run buffer tests on the electrodes Note DO NOT ADJUST THE ANALYZER 7 0 buffer write down reading and response time 4 0 buffer write down reading and response time Slow response Clean again or acid clean overnight in electrode wash solution A1100091 Make sure that after cleaning response is not more than 3 minutes Reference lf pH 7 0 reads between 6 and 8 then reference is good If outside 6 to 8 then reference is poor or has failed PH Glass Subtract pH 4 0 reading from pH 7 0 reading if 2 5 to 3 0 is the result the glass is good if less than 2 5 then the pH electrode is dying and should be replaced Dying pH electrodes can sometimes be regenerated with A1100092 electrode renew solution THIRD If electrodes pass tests then they are good Place electrode back in the loop and then run a 2 buffer calibration following the instructions in this instruction manual FOURTH If the electrode fails the tests a Replace the pH electrodes b Consider returning electrodes to IC Controls for failure analysis if you think that electrode life was short IC Controls offers a free cause of failure and application analysis that may help you get longer electrode life 615 26 Instructions Page 15 IC CONTROLS Troubleshooting Error a
23. ns the exhibited pH These dissolved substances are in the solution in ion form which makes such solutions good conductors With 1 000 micro Siemen conductivity of mobile ions pH electrodes have a good circuit and give fast accurate pH readings When Pure Waters are encountered standard pH electrodes begin to exhibit less reliable results They seem to respond more slowly appear to drift and do not reproduce calibration results between Buffers and Grab Sample On Highly Pure waters pH electrodes become jumpy flow sensitive and apparently inaccurate Pure Water is a relative term for Low Conductivity Waters of less than about 500 micro Siemen IC CONTROLS has observed some of these effects on waters between 50 and 500 micro Siemen most likely due to pH Buffer carry over on the pH electrode IC CONTROLS considers waters below 50 micro Siemen to be High Purity samples and recommends High Purity modification on all samples less than 15 micro Siemen We consider waters below 5 micro Siemen to be Ultra Pure and recommend Ultra Pure modification on all applications below 1 micro Siemen Typical Pure Water Streams are Micro Siemen 1 purified effluent waters 50 to 250 2 surface waters in high rain areas 25 to 150 3 well waters in high rain sand soil areas 50 to 100 4 process water in purification plants 5 to 150 5 process condensate waters 5 to 100 6 steam condensate 1to 15 7 boiler feed water 1to 15 8 reverse osmosis and distilled waters 0
24. nsequential damages whether the claims are based in contract in tort including negligence or otherwise with respect to or arising out of the product furnished hereunder Representations and warranties made by any person including its authorized dealers distributors representatives and employees of IC CONTROLS which are inconsistent or in addition to the terms of this warranty shall not be binding upon IC CONTROLS unless in writing and signed by one of its officers 615 26 Instructions Page 27
25. ons people encounter difficulties One reason is the pH scale 0 to 14 which looks simple and linear but as can be seen above is actually a logarithmic change of 1 to 10 between any two numbers A second reason is the difference between mole and normal 1 mole is defined as 1 x the molecular weight of a substance in grams 1 mole is actually 1 Avogadro number 6 023 x 10 of atoms or molecules and 1 molar is defined as 1 x the molecular weight of solute in 1 liter of solution For substances with complex formula s the molecular weight is the formula weight of the combined molecules Once formula s get involved it is easy to see the inpact on pH hydrogen ion going from 1 molar HCI to 1 molar H2SOa clearly the H ratio is not unity To make it easier Normality is introduced and the equivalent weight of the substance is used instead of the formula weight 1 normal is defined as 1 x equivalent weight of solute in 1 liter of solution In pH acid base reactions one equivalent is the number of grams of a substance that combines with or supplies one Avogadro number of hydrogen ions So 1 eq of HCI 1 mole or 36 5 g of HCI and is 1 normal wheras 1 eq of H2SO4 1 2 mole or 49g of H2SO4 not 98g and is 1 normal Therefore a 1 molar H2SO4 solution 98g L is 2 normal 1N H2S04 is 49g L So eq wt formula wt number of H ions The advantage is a given volume of a normal solution will react with an equal volume of another solution having th
26. ound terminal If a BNC shorting strap is used connect the wire lead end to the solution ground terminal This will give you a O mV input which is the same as pH 7 BNC Fitting O 9 S S Paper Clip Short Note the pH reading and if it is approximately 7 then the analyzer looks alright O reading and the offset FOURTH Problem isolated If the reading is far from 7 pH do a single point calibration and note the pH If the offset is within 10 mV of zero then the analyzer wiring and preamp are good If the analyzer and the equipment are good then the problem is in the probe refer to the pH electrode troubleshooting section below If the offset is greater than 10 mV the problem may be in the equipment analyzer wiring or preamp refer to the analyzer troubleshooting section 615 26 Instructions Page 13 IC CONTROLS Troubleshooting Analyzer Problem Troubleshooting If the offset is higher than 10 mV check the wiring between the preamp and its terminal block and see if there are any loose or faulty connections Frayed corroded or broken wires here are the most common cause of equipment problems If the wiring looks good and after recalibration the large offset is still there a Use the paper clip U at the analyzer terminal block and short between the reference common and the signal This procedure bypasses the preamp and wiring b A new single point calibr
27. pH sensor Low conductivity waters age pH sensing glass quickly causing it to become insensitive Regular replacement makes sense to ensure actual pH changes are detected An insensitive pH electrode may provide a satisfying steady pH reading at an average value for the application but fail to warn of adverse pH changes Pure waters also leach the salt from the junctions of reference electrodes This may be seen as pH drift or large offset readings in microprocessor analyzers Page 12 615 26 Instructions Troubleshooting Troubleshooting IC CONTROLS When trying to determine what the problem is with a pH loop there are a few simple steps to follow Isolating the Problem FIRST Write down the symptoms a pH reading b temperature reading c pH offset and slope SECOND Separate the sensor from the analyzer so that the problem can be isolated Disconnect the sensor from the analyzer at the BNC fitting see diagram In this way it is much easier to test and determine if the problem is in the pH sensor or in the analyzer A THIRD See if the analyzer reads correctly by inputting 0 mV 0 mV 7 pH a Take a paper clip and bend it into a U shape or use a BNC shorting strap if one is available Insert the paper clip in the analyzer input BNC connector shorting between the center pin and the outside ring then add a jumper from the paper clip to the solution gr
28. quality glass pH electrode plus a pH neutral additive to adjust conductivity and special diluted pH buffers already containing the same background of pH neutral additive Adding adjustor to samples increases the conductivity reduces jumpiness and improves response time Since the same amount of adjustor is added to the buffers and the samples any net pH effect is standardized out and becomes negligible Contamination due to carryover from high conductivity buffers is minimized Liquid junction potential variations are minimized because the buffers and adjusted sample have similar conductivity 615 26 Instructions Page 5 IC CONTROLS Pure Water pH Measurement On Line Solutions IC CONTROLS has developed procedures to calibrate On Line pH Flow cells in use on Low Conductivity Samples which take the above problems into consideration The flow cells are specially constructed to deal with the effects of low conductivity on pH measurement Also dilute pH buffers and low conductivity sample handling procedures have been developed to ensure good calibrations Supplies for these procedures are available as A1100217 Low Conductivity 7 0 pH Buffer 500 ml A1100217 6P Low Conductivity 7 0 pH Buffer 6 PAK A1100216 Low Conductivity 4 1 pH Buffer 500 ml A1100216 6P Low Conductivity 4 1 pH Buffer 6 PAK A1100218 Low Conductivity 10 2 pH Buffer 500 ml A1100218 6P Low Conductivity 10 2 pH Buffer 6 PAK A1100219 pH Neutral Conductivity Adjust Soln 125 ml A1
29. re in Software greater than Configuration section 105 Connect resistor to TC terminals to simulate a constant temperature Temperature Verify process and sensor location greater than 105 C Electronic Follow procedure in Hardware calibration Alignment section necessary Page 18 615 26 Instructions Troubleshooting IC CONTROLS Checking The Automatic Temperature Compensator The temperature compensation element is a temperature sensitive current transmitter and can be checked with a voltmeter Voltage increases with a rise in temperature The element will read 0 300 volts 1 at 25 C on terminal T with a 655 analyzer properly wired up Checking the Reference Electrode The reference electrode can be checked using either a portable digital pH meter model 659 or another known good 615 reference side and a digital voltmeter To check with a portable pH meter use the reference in place of the meter s normal reference cell The reading should be within 0 1 pH unit of the correct value If no secondary pH meter is available the following test can be made A voltage reading taken between any two reference elements should be less than 10 mV Anything more than this indicates that one of the units is defective Using three elements makes this method almost foolproof because the bad one will give nearly identical large readings with each of the good whereas the good pair will read less than 10 mV With low conductivi
30. te 1 These instructions below only cover the special grab sample collection handling and calibration needs for pure water samples going to the laboratory for analysis Follow the instruction manual procedure for the on line pH analyzer to properly enter the grab sample results Note 2 Ensure Grab Samples are handled as described Use of full strong pH buffers for Lab Analyzer Calibration and carrying pure samples in open beakers will result in bad calibrations Note 3 Grab Sample Calibration is only single point calibration or Standardization for the on line analyzer In high purity water samples pH electrodes dehydrate and become short in span as well Two Buffer Calibration using pumped Low Conductivity Buffers to periodically establish slope or efficiency is also recommended Before measuring pure water samples always perform a two buffer calibration on the Laboratory analyzer using fresh A1100217 pH 7 and A1100216 pH 4 or A1100218 pH 10 low conductivity buffer Use a magnetic stirrer with a piece of cardboard for thermal isolation when measuring pH in buffers and sample Before placing pH electrodes into solution rinse the electrodes over the drain with some of the solution to be measured Do not wipe the pH electrodes since contamination and or polarization are probable with low conductivity samples 1 In the field draw a sample into a 500 ml bottle at the on line pH sensor with the sample feed tube submerged A
31. tlet directly always use the atmospheric drain Drains direct connected to the 615 will affect the pH reading Checking the pH Measuring Electrode Remove the protective cap from the sensor element Visually inspect the sensing tip for any signs of damage it should be clean and damp with no cracks If the sensing tip is dry or has salt crystals stuck to it soak overnight in 4 0 pH buffer Checking the Reference Immediately prior to sensor start up remove the reference cell from the flow cell body Check the liquid junction of the reference cell before proceeding If dry crystals are visible on the junction dissolve them off Prepare the O Ring for reinsertion by lubricating with a trace of silicone grease Check that the BNC connector is clean and dry If water traces are present refer to the Troubleshooting section for instructions Checking The Temperature Compensator And Preamp The temperature compensator is a constant current device At 25 C 0 3 VDC will show up between the Temp and ref terminals when wired to a 655 analyzer A basic preamp check can be performed by shorting the center pin of the BNC jack to the reference electrode and solution ground terminals The sensor must be correctly wired to the analyzer for these tests The analyzer should read 7 0 0 1 pH if it does not refer to the Troubleshooting section for instructions Typical Flow Mounting The distance between the actual process and the pH sensor should be
32. to the calibration bottle or attach the buffer bottle and puncture with a tack to allow gravity flow Turn the three way valve up to gravity feed Low Conductivity pH buffer to the pH sensor at the same flow rate that the sample is normally flowing Be careful not to introduce air 2 Rinse the pH electrodes for at least 10 minutes 2e When the reading is steady calibrate the on line meter Buffer 2 to display the pH value of the buffer used 10 Make a note of the Standardize Offset and Slope efficiency of the pH electrodes 11 Replace the buffer with 500 ml of the sample Sangard Instalo collected in step 1 and gravity pump to rinse the second buffer out of the system and flowcell at the flow rate noted in step 2 Note the sample pH The analyzer is now properly calibrated for slope 12 Return the flowcell to sample and adjust the flow rate to the rate noted in step 2 13 Wait 1 hour then note the sample pH and compare with the pH from step 11 If the pH readings agree then the calibration Standardize and Slope are both good If the sample pH is normally steady and a differential exists do a Grab Sample Calibration to Standardize for apparent Liquid Junction Potential For LARGE OFFSET soak the pH electrode overnight in A1100216 4 buffer plus 5cc of A1100219 Neutral Conductivity Adjusting Solution and try again If the problem persists replace the pH sensor For LOW EFFICIENCY less than 85 try to reacti
33. ty applications the on line electrode is the most likely reference to have the offset Checking the Glass Electrode This is the most difficult part to check properly The only alternatives are replacing it or trying it in another pH system Test by trying it with a portable digital analyzer IC CONTROLS analyzer calibrator 659 Bad glass electrodes show limited response or no response at all they seldom become noisy A steady reading of 3 6 pH regardless of the buffer solution used indicates a cracked electrode bulb A steady reading near 7 0 pH can be caused by a dirty or internally shorted connector or cable Test for shorts with a good ohmmeter at least 50 meg ohms separation is needed between the center conductor and outside of the fitting Repair by replacement Slow response electrodes can often be rejuvenated by soaking for 2 or 3 hours in A1100091 pH electrode wash solution Sometimes cycling back and forth 4 to 8 times between 4 and 10 buffer will soeed up pH electrode response where low conductivity has aged the electrode If the electrode has just had it response will be unalterably slow and or low efficiency It must be replaced in this case Electronics wiring Problems With low conductivity water samples the water itself has a high resistance and provides a good isolation to the pH sensor turning it into a first quality antenna Keeping the antenna 100 shielded and the solution grounded is important Jumpy readings
34. ubtract the orrigionally noted pH value from the confirmed pH value step 11 the difference is the offset that must be added or subtracted To install the difference in a 655 pH meter multiply the difference by 59 1mV example 0 5pH x 59 1 30mV then edit the offset to add or subtract the mVs To install the difference in analog meters add or subtract the difference to the current pH reading using the standardize or offset adjustment Two Buffer Calibration Procedure for Two Buffer Calibration ur using gravity pumped Low Conductivity pH i Buffers in the on line 615 26 pH Sensor 1 Use only special Low Conductivity pH Buffer for this procedure Use of full strength pH buffers for on line Analyzer Calibration will result in apoian very long stabilization time when returning to Low Conductivity Sample 2 Gravity pumped buffer calibration requires a 615 26 head based Ultra Pure pH sensor with a sample head tank buffer head tank and a three way valve in the sample feed line to the on line pH sensor 3 Use care when gravity pumping to minimize air getting into the sample line lack of exposure to carbon dioxide is a big advantage to pumped buffer calibration Wipe the outside of the used sample tube clean and put a finger over the vent in the vacuum breaker tee while collecting to prevent air from mixing with the sample and lowering the pH as it travels down the tube Puncture the bottle 1 Draw several samples into 5
35. uffer capacity is small Absorption of carbon dioxide on exposure to air will result in carbonic acid formation and cause a real change in pH Most often this is seen as a change in pH drift from the original field reading and the same sample back in the laboratory This fact can be readily demonstrated by taking a beaker of fresh demin water from a laboratory column with pH electrode inserted and showing approximately 7 pH then bubbling compressed air through it and observing the pH reading quickly fall to between 5 to 5 5 as it reaches saturation For on line samples in stainless line this is not a problem until someone draws a sample to take to the lab for comparison and it absorbs carbon dioxide along the way Laboratory Solutions Common laboratory remedies for these problems use a low resistance pH electrode and a reference with a fast electrolyte flow When placed in a low conductivity water sample the pH electrodes exhibit faster response and more stability due to the addition of salt from the reference raising the sample conductivity and due to dissolution of the low resistance glass into the sample at the glass surface if the conductivity is low enough While both raise the conductivity they both may change the pH seen at the glass pH electrode Stable pH readings are reached sooner at the cost of pH error dependant on the added ions A further step was introduced by Orion Research in the early 1980 s The addition used a research
36. up evaporation from a dish of water by heating or boiling it clearly the user needs to make provision for the effects on the measurement Reference Electrodes A pH reference electrode completes the electrical circuit to the outside of the pH measuring electrode by providing a means to release ions into the process while at the same time duplicating the thermocouple type temperature dependant error voltage generated inside the pH measuring electrode when it s fluid and solid conductors meet Thus the reference both completes the electrical path and produces an identical when referenced to the glass electrode error voltage reference voltage which appears with opposite polarity to the pH meter and cancels all but the pH signal produced by hydrogen ion presence Clearly process ions travelling backwards in the reference electrode ion release route can if they react with the reference internal change the reference voltage causing drift High concentrations of process ions can change the nature of the reference fill so that an entirely unwanted voltage results Reactions can precipitate certain components and or block the ion routes producing an unwanted voltage drop in series with the pH signal as can films or coatings of material from the process IC CONTROLS have developed ways of dealing with these problems and once identified our staff will be pleased to assist Call us toll free at 1 800 265 9161 if you have any questions pH in Low Condu
37. vate by cycling between 4 buffer and 10 buffer from 4 to 8 times or try to reactivate by soaking 24 hours in A1100091 pH electrode wash solution For VERY LOW EFFICIENCY less than 70 try to recover with A1100092 pH Electrode Renew solution for 20 minutes followed by demin rinse then A1100091 electrode wash overnight If the low efficiency remains replace the pH electrode with a new one Start flow clear bubbles Page 10 615 26 Instructions Maintenance IC CONTROLS Maintenance Daily Sample Flow Inspection Check the sample flow to the pH Sensor ensure it is fairly constant IC CONTROLS recommends 20 to 40 ml per minute The head tank should be full to the upper fitting and 10 200 ml overflowing to drain If sample flow to the pH sensor stops but sample is flowing through the head tank can be caused by gas bubbles released from the sample restart by putting a finger over the vacuum breaker white tee vent and the outlet end of the overflow tube untill the bubbles pass through and flow continues when released Weekly pH Reading Check Check accuracy by taking a grab sample from the used sample flow at the atmospheric drain Use the same sample gathering proceedure as for a grab sample calibration Wipe the outside of the used sample tube clean and put a finger over the vent in the vacuum breaker tee while collecting to prevent air from mixing with the sample and lowering the pH as it travels down the tube Analy
38. zer Diagnostics Record Calibrate the system if necessary and keep a record of Offset Efficiency Flow rate and Temperature Frequent large offset and slope changes indicate a problem exists Refer to the Troubleshooting section in this case Quarterly Place the pH analyzer in STANDBY Shut off flow of sample through the sensor and drain the flow cell pH Electrode Inspection The pH sensor cartridge can be removed from the flow cell body by turning counter clockwise on the retaining nut With the sensor removed the glass pH electrode may be inspected and cleaned if necessary Generally the pH electrode will be OK so no action is needed Establish pH Sensor Efficiency Run a 2 buffer calibration to ensure pH electrode efficiency is OK See Calibration section for instructions Reassemble the flow cell using only finger tight pressure on the pH cartridge retaining nut Turn on the sample flow and check flow rate is same as normal Establish the Offset Allow 30 minutes for the electrode system to purify and then do a grab sample laboratory calibration This calibration will establish any offset due to the samples low conductivity 615 26 Instructions Page 11 IC CONTROLS Maintenance Analyzer Diagnostics Record Keep a record of Offset Efficiency Flow rate and Temperature Frequent large offset and slope changes indicate a problem exists Refer to the Troubleshooting section in this case Annual Routine Replace the 615
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