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1720D Low Range Process Turbidimeter SERVICE MANUAL

1. 7 52000 98 1 5V 15 B REVISIONS u5 u5 u5 u5 ut U2 u6 UB Uto Ut u12 UB REV DESCRIPTION DATE APPROVED 7 22 26 40 32 1 14 7 8 1 28 4 TPA8 T cat A PRODUCTION RELEASE KLS SK LM 5V 5V 22 oe cs de dle aye edad 5 T Dim B REVISED PER ECO R 155 97 9 12 97 SK KLS LM LAS AR AR AO RA Hanc 50 VDC C25 C26 C27 C34 C35 C36 C28 BAV99LT1 50 Voc 023 c5 20 106 coi looi loo oor joo looi looi C REVISED PER ECO R 370 98 3 9 98 D3 0 1 0 1 TP49 5V 50 voc 50 VDC TP4
2. h asis 46308 00 Signal Output Module SOM a i E a a aaea tres aiaei ie each 51250 00 Serial Input Output Module SIO 115 V 50 60 Hz with 120 V power supply each 52074 00 Serial Input Output Module SIO 230 V 50 60 Hz with 230 V power supply each eau 52074 02 StablCal Calibration Kit for the 1720C 1720D Turbidimeter includes StablCal Standards lt 0 1 NTU 20 0 NEU oto eerte o e tet 1 L each 26596 00 Stabi al Standards 10 NTU 6 ette oreet tds T E e 26598 53 Swabs Cotton presterilized for photocell cleaning oooonnocnnnccnocononoconcconncnoncnnnncnnncnnncnnncnnns 100 pkg 25543 00 TenSette Pipet O Lil ME ts uei cron cs en hn Eee dante le et deed BAD scisco 19700 01 TenSette Pipet Tips 0 1 to 1 0 ML usn d deti obire He bol Eb s i eise acit ba te 710 01 lt A 25588 00 Ten Sette Pipet OTTO IM is e 19700 10 TenSette Pipet Dips Onl do VOM AAA Ads 50 pkg 5 4 miso 25589 00 U Bolts for PS1201 AquaTrend pole mounting teens 2 pkg 251410 00 56
3. Carefully install the new flash memory in socket U1 with the proper orientation Orient the memory chip so the angled corner of the chip aligns with the angled corner in the socket Press the memory chip firmly in place until it is seated in the socket g Ifnecessary press the gasket back into the groove in the top of the 1720D head Place the top half of the 1720D cap back on the bottom half of the cap ensuring the gasket is properly seated and no wires are pinched h Apply Locktight Cat No 41437 00 to the threaded screw holes and reinstall the five Phillips screws on the underside of the 1720D head i Place the 1720D head back on the body j Restore power to the 1720D head Ensure the green power LED is illuminated Note The 1720D is unconfigured at this point configure LED flashing and must be replaced using the AquaTrend Network menu before it will communicate with the AquarTrend or other network devices 3 Replace the 1720D from the AquaTrend Network Menu a Press the MENU key on the AquaTrend Select NETWORK MENU followed by REPLACE DEVICE b Select CONTINUE 43 SECTION 5 continued The AquaTrend will search for unconfigured devices If more than one sensor is unconfigured the AquaTrend will prompt for the configure button to be pressed on the device that was upgraded d The AquaTrend will replace all network connections to DDM SOM SIO etc e Restore all settings in the measurement opti
4. Typically LOW SIGNAL indicates the head was not seated on the body while the 1720D was powered up Selecting ZERO ELECTRONICS from the CALIBRATION menu re reads the dark counts Alternatively power can be cycled to the 1720D which also re reads the dark counts Other possible causes of LOW SIGNAL are disconnected photodetector leads a bad photodetector or a bad amplifier circuit 4 2 6 Clearing the Sensor Alarm Log MAIN MENU ALARM LOs AGUATREND MENU El SENSOR MENU OTHER DEVICE MENU NETWORK MENU Press DISPLHY To Show Data Pe ee SENSOR MENU SELECT SENSOR E 17240 TURE 17260 TURE 17200 TURE 17200 TURE 81 1728D 82 1728D 43 1728D 44 1728D CE TGE TEK SENSOR MENU E SENSOR DIAGNOSTICS EDIT MAME CETE TET To clear the contents of the 1720D alarm log perform the following steps 1 Press the MENU key to access the main menu Move the pointer to SENSOR MENU and press the ENTER key 2 Select the appropriate sensor and press the ENTER key 3 Select SENSOR DIAGNOSTICS and press the ENTER key 4 Select CLEAR ALARM LOG and press the ENTER key 5 Move the pointer to YES and press ENTER Reviewing the alarm log will show NO ALARM ENTRIES until an alarm power up or sensor warning occurs SENSOR MENU 17260 TURE 4i 172HD SENSOR DIAGNOSTICS SENSOR MENU CLEAR ALARM LOG PRIHT TURE SETUP E CLEAR ALARM LOG SENSOR COLD START SENSOR RESET CETE TET B1 B1 37 66 81 36 SECTION 4 conti
5. 12vF E Y ix QUANITITY PER SUFFIX DESCRIPTION NOTE DES PART NO ITEM Ul 16 32 1 8W 25v 499 1 1 8W PARTS LIST U2 7 14 TAF 32 498 1x ik 1 RH U5 8 9 19 7 20 22 26 TP59 Ris R12 FOR GENERAL REQUIREMENTS NOTICE Hoch Compony cloims proprietory rights in the informotion on this drowing It is issued in confidence 21 25 39 40 41 44 12 SEE HACH STANDARDS for engineering information only and moy not whole or in part be used to monufocture anything whether or U6 7 14 LA is DIMENSIONS ARE IN INCHES not shown hereon reproduced or disclosed to onyone without direct written permission from Hach Company UB 7 4 US z z 107 Leos tebe us DO NOT SCALE THIS DWG own 11 8 95 KLS H A E H C O M p A N Y TP60 GREEN YELLOW ELOY MATL u10 3 8 Y Y Y CHK Ul m i i x LOVELAND COLORADO AMES IOWA 6 52000 00 U12 14 28 a ae La 2 C A ENGR TITLE 52xxx 00 SCHEMATIC 74HC00 NOTES d 14640 1720D PROCESS TURBIDIMETER EE QA RESISTOR VALUES ARE IN OHMS SHT SIZE REV SIZE DWG NO REV 2 CAPACITOR VALUES ARE IN MICROFARADS U d Gat LED die t Se VISION STATUS 52000 00 REL nuse ates E ndicators C 52000 98 C OF ene NEXT ASSY USED ON SCALE sur 10F2 DWG NO SH 52000 98 2 REVISIONS REV DESCRIPTION DATE APPROVED NOTE FOR Ulf THIS BOARD ASSY MAY HAVE FTT 10 OR FTT 10A PART AT REF DESIGNATOR U11 THE SCHEMATIC DIAGRAM FOR THE FTT 10 PART IS REPRESENT
6. 8 Voltage Measurements 1 ur ED DEEP ERE EE ER Ee LER ge e DeL EH EIE a PUE TT 29 3 3 Troubleshooting Procedures pete eee as Hao HER ans 30 3 3 T Cold Start A entre ep dette tinet db ete etie e rele Gabe de era ieee 30 3 3 2 Manually Unconfiguring the 1720D 0 celica eesesecesseceseeeaeceseesseeceseceaecaecaeceseeeeesseeeaeeseaeeaaesseeeeeeseeeeseeenaes 31 SECTION DIAGNOSTICS a en ihe AA t uiti eu UR dd 33 4 1 Neuron Chip Diagnostics sain une de e pere e eee eed ee tpe E ete aepo 33 42 Sensor Alarm LOg cete nete A tb e er e A etr Patente 33 4 2 1 Reviewing the Sensor Alarm Log sees eene nennen nne nnne aE entretenir enne 33 4 2 2 Alarm Begin 5 22 ou tpe it re fee He bec e RH ai eed eei e Pe biie 34 4 2 3 Alarm End gren TP RE patet tec d t oes 34 4 2 4 Power Ups iR eR MEER RE eR ecu 34 4 23 Sensor Warning 2 uem de rie M Eure RE EH eee E Eg ee Rel Eb be LEE Rae 34 4 22 51 ALD TIrimeout edere aire b P TP PR RP ERRARE ERO ek ERR Re o AO 34 42 5 2Iaght Beal thc t db t e en ttti dtt 35 4 2 5 3 Bad eam prises xn mrt mee RE Et PR A I D praet PE M eee rette do 35 D SE UI 36 42 5 Low Signal i EHE eee RE Ete det tti ete E Er 36 4 2 6 Clearing the Sensor Alarm Log eter tee a ei ESPERE Eee agere ER ds 36 4 3 Service Menu ACCESS couette etai ee e eee enter Pee ive ioo aes e e e ehe tes es been b cite tects 37 4 4 Display Startup Values eb id e ee CUP e Ge a MEHR ee
7. A sample screen of each type is shown below SENSOR MENU SENSOR MENU TYPE NORMAL CAL TYPE COMPARATIVE CAL DATE 6101 97 00 66 DI WATER 8 144 NTU 1 368 NTU GAIN 8 971 ERROR MONE B1sB1 37 CETE TET The first line indicates the type of calibration either NORMAL CAL or COMPARATIVE CAL e The second line indicates the date and time the calibration was performed e For anormal calibration lines 3 and 4 display the value of the DI water and the second standard typically 20 NTU For a comparative calibration line 3 displays the value of the lab instrument comparative reading The gain line denotes how close the calibration is to the default calibration pre programmed into the software A gain value of 1 0 denotes a calibration that exactly matches the default calibration Values outside the range of 0 5 to 2 0 trigger QUESTIONABLE CAL at the end of either calibration procedure This value can be overridden and accepted by selecting Accept Calibration however the error field will be set to BAD GAIN The gain value varies based on lamp age electronic drift and cleanliness of the lens and detector e The error line displays an error that may have occurred during the last calibration NONE is displayed if no error was encountered during calibration The following table lists each calibration error type Table 4 Calibration Errors NONE No error BAD GAIN Gain outside 0 5 to 2 0 limi
8. DATE 81 81 97 86 68 61 61 97 4 2 5 Sensor Warning ALARM LOG OE Sc sensor Warning TYPE HI DARK COUNTS DATE 81 61 97 66 88 aivaisa H 4 2 5 1 A D Timeout The 1720D alarm log is maintained across power outages so alarm events before a power outage can be viewed after power is restored The begin alarm condition is displayed as AL1 BEGIN or AL2 BEGIN depending on the alarm number This entry indicates a set point alarm started and shows the time date type set point and turbidity value that triggered the alarm The end alarm condition is displayed as AL1 END or AL2 END depending on the alarm number This entry indicates that a set point alarm completed and shows the time date type set point and turbidity value that ended the alarm Power up is always the first entry in the alarm log The date and time the instrument powered up is displayed along with the POWER UP message A date time of 01 01 00 00 00 indicates the 1720D has not received date and time from the Master AquaTrend In software version 2 0 multiple power up entries were recorded in the alarm log If the microprocessor detects a problem within the sensor electronics the alarm log displays SENS WARN The type of sensor warning and the time and date the warning occurred are displayed Sensor warnings are automatically acknowledged the number is removed from the lower portion of the screen when the sensor alarm log is first displayed The 17
9. Supply i a erai e cease nse e er EE E een e E dene ee each Lid Bubble Trap 1720D 14 rte eee cert tet eee terree sane Carree Pee Lee each 1720D Service Only Replacement Parts Aperture for T720C7 T720D tete oe tete teet ida each Barb fittings 15 ID x 2 NPT iude a each Body and bubble trap assembly sees eee nnne eterne rennen each Bubble Trap de Re tege He t e i oe ote tdeo each Bubble Trap Lidia eot ient tes pecie resi t ag eto ee iae each Cable assembly lamp to 1720D circuit board esssesseeeeeeeeeneeeeeee neret each Cap DOLLOI ette d stie LEER ba laceebasegseneduses oabadaeusacognoesse ERREUR E rrRet eee Lr Reed each Cap EU each rele de i te ae ia Ara a lee tle on a a a ata each Connector receptacle 5 circuit female sealed each Gasket for 1720D cap neo t tice O ica each Eabel for front of 1720D Cap ic i ierit He e e e ass mee e ene each Lens Tor 1720C 1720D A eere tte oe este erp een Re tory eer each shade for 1720 1 220D s s iste ices cs eo aeter t bete retis ee e tedio e e Rs each SoftWare upgrade Kit setenta Anita ias each Tube fitting 4 OD am le nip teri rere Fee e rd anstatt da each 1720D Optional Accessories Calibration Cylinder attire eco Ta e deste EP A nee ree Pee aaa ae each Cap Connector Receptacle edente tese n Ee a ROI ESI lio tierra each Communication Cable 22 gauge 2 conductor shielded sss per fo
10. The 1720D Turbidimeter incorporates a number of self diagnostic functions to monitor key performance parameters Continuous diagnostic functions are used to detect system failures and to actuate sensor warnings The Alarm Log stores pertinent information about alarms and sensor warnings and in many cases indicates the nature of the failure This instrument is certified to UL CS A EU safety standards as well as RF emissions and EMC immunity standards To assure continued compliance replace components with current version parts 3 2 Troubleshooting Tables The following sections provide troubleshooting tables for a variety of topics Each table lists symptoms possible causes and corrective actions See SECTION 5 on page 41 for specific repair procedures 3 2 1 Underrange Overrange If the sample being measured is outside the instrument range 0 100 NTU or malfunction occurs with the instrument an underrange or overrange condition may occur These are defined as follows Underrange is indicated by a negative reading and typically indicates an improper calibration failure to zero electronics properly or a burned out lamp e Overrange is indicated by a continuous reading of 100 NTU and typically indicates an improper calibration or that the sample being measured is more turbid than 100 NTU Table 5 Underrange Troubleshooting Table Symptom Possible Cause Corrective Action Low readings Continuous underrange
11. To change the mux setting select MUX CHANNEL then press ENTER Test mode is automatically set to ON Under normal operation the multiplexer is set to the detector channel In this mode the A D measures the voltage from the photocell amplifier circuit Alternatively when the multiplexer is set to 5 volts the A D measures the voltage from the 5 volt voltage divider See Section 1 5 on page 8 for more information on the multiplexer The third line of the test mode menu displays the current amplifier setting To change the amplifier setting select AMP SETTING then press ENTER Test mode is automatically set to ON when either option is selected Under normal operation the microprocessor automatically selects the appropriate amplifier gain setting depending on the turbidity of the sample The amplifier gain switches from high to low at approximately 10 NTU In X1 mode the relay in the photocell amplifier circuit is opened causing the lower gain In X32 mode the relay in the photocell amplifier circuit is closed raising the gain by a factor of 32 See Section 1 5 on page 6 for more information on the photocell amplifier circuit 39 SECTION 4 continued 4 5 3 Lamp Setting 4 5 4 Millivolt Display WARNING The 1720D automatically switches units from NTU to mV millivolts when millivolt display is selected The AquaTrend data log for this channel is erased when the switch occurs Do not select millivolt dis play if the data
12. _ OK _ V sosed 475K 1 x 475 0007 The difference in gain is approximately 32 times The software automatically selects the appropriate gain setting depending on the photocell current See Section 4 5 on page 38 for information on manually setting the amplifier gain SECTION 1 continued Figure 2 1720T Turbidimeter Head Components Configure Button Configure LED Yellow A Power LED Ach Green C CONFIGURE GS 20 Status LED Yellow Remote Device Connector Photocell Wiring Photocell Assembly 1 5 2 2 System Voltage Divider Lamp Wiring 7 Photocell Shade A voltage divider is used to scale the 5 system volts so it can be measured by the A D converter The equation describing the output voltage is given by v 1k out 1k 1 49k Min 0 4021 With a system voltage of 5 0 volts the resulting output voltage is 2 01 volts This is within the 2 5 to 2 5 volt measurable range of the A D converter The 5 system voltage orange wire from the PS1201 is measured and the value is stored with the lamp off at startup This value is periodically re measured with the lamp on and compared to the lamp off value If the two are the same i e no voltage drop there is a problem with the lamp or lamp drive circuit and the BAD LAMP alarm is stored in the alarm log See the Display Startup Values section for more information on viewing the 5 system volt
13. as a buffer between the connector and Neuron chip to ensure transients or noise do not damage the Neuron chip The opto isolator is connected to the same pin as the configure button so either can trigger sending the configure message Three LED indicators display information about the operating state of the 1720D as described below in Section 1 6 5 1 through Section 1 6 5 3 The green power LED is lit during normal operation indicating power is being supplied to the 1720D This LED is powered directly off the 5 system voltage No indication is given for the 12V system voltage If the power LED is off no 5 system voltage is being supplied to the 1720D or the wiring is not properly connected Refer to the PS 20 Power Supply Manual Cat No 52010 18 for detailed wiring information 12 SECTION 1 continued 1 6 5 2 Configure LED 1 6 5 3 Status LED 1 7 Software 1 7 1 Power Up The yellow configure LED provides information about the state of the Neuron chip The configure LED is always lighted for Y2 second immediately after power up continuously flashing configure LED indicates the 1720D is unconfigured and is ready to be added by the AquaTrend A steady off configure LED indicates the 1720D is configured and is running its application program A steady on configure LED indicates a problem with the Neuron chip See the Configure LED Troubleshooting Table for more information on the configure LED The yellow status LED b
14. converter circuit failure Look for A D Timeout in sensor alarm log Cycle power to instrument Replace circuit board Unconfigured sensor Look for flashing configure LED on 1720D head Use AquaTrend REPLACE DEVICE function to restore proper operation Bad 12V red wire 5V orange wire or ground black wire connection Check red black and orange connections at power supply and on circuit board 26 SECTION 3 continued 3 2 3 Questionable Cal If the 1720D detects a potential problem during the calibration procedure the message QUESTIONABLE CAL is displayed during the last step of the calibration procedure If the calibration is accepted at this point the error entry in the CAL HISTORY screen will display one of the errors shown in Table 8 These errors can only be cleared by recalibrating the instrument Note that only one error is displayed even though multiple error conditions may have occurred Table 8 Questionable Cal Troubleshooting Table Symptom Error Possible Cause Corrective Action None No calibration error detected None Valid gain values are 0 5 to 2 0 Check the Bad Gain Gain is out of recommended limits calibration standards and repeat the procedure If the problem persists replace the lamp Calibration standards were read backwards Repeat the calibration procedure with the Not Ascending highest value standard first standards in the pro
15. information Photocopy and fill out the checkout sheet found on the last page of this manual for each instrument repaired The checkout sheet provides important information for the customer when shipped with the repaired instrument Begin repair procedures by performing the tests listed in the Checkout Sheet Procedure After identifying the instrument s symptoms refer to SECTION 3 on page 25 to help identify the possible causes s and to locate related repair procedures Use SECTION 4 on page 33 as a guide to pinpointing specific problems before repair and to determine if the instrument is working properly after repair Repair procedures are found in SECTION 5 on page 41 1 2 Serial Number History The 1720D Low Range Process Turbidimeter is found in the Hach Products for Analysis PFA as Cat No 52000 00 This number refers to the instrument plus all standard accessories A label affixed to the back of the instrument gives the instrument only Cat No 52000 60 The 12 digit serial number is also listed on this label The serial number begins with the year and month of manufacture i e June of 1997 is 9706 followed by an 8 digit number that is incremented for each instrument produced Table 1 Instrument Version History S N Date Description Software 971000000101 10 28 97 Initial production release Potential for wrong resistor on circuit board R23 2 0 causes A D Timeout error log entry 980100000500
16. menu selection in SENSOR DIAGNOSTICS e Visible display of test mode menu selection in SENSOR DIAGNOSTICS AGUATREND MENU E AGUATREND MENU gt AGUATREND MENU Ll AGUATREND DIAGNOSTICS AGUATREND DIAGNOSTICS o DISPLHY TEST DISPLAY TEST KETBEOHRD TEST KETBEOHRD TEST CANCEL SERVICE ACCESS MEMORY TEST MEMORY TEST B ves VERIFY PROGRAM CHECKSUM VERIFY PROGRAM CHECKSUM Ha CLEAR ALARM LOG CLEAR ALARM LOG AGUATREND COLD START AGUATREND COLD START SERVICE MENU SERVICE MENU E 5 EE 5 359 CE TGE TET 37 SECTION 4 continued 4 4 Display Startup Values The startup values menu displays the current dark readings millivolt detector readings at each gain setting with the lamp off as well as the 5 system millivolt readings with the lamp on and lamp off Note The AquaTrend SERVICE 1 Enable the Service Menu using the instructions in Section 4 3 on page 37 MENU must be enabled to perform the following steps 2 Press MENU on the AquaTrend Select SENSOR MENU 3 Press ENTER to select the 1720D MAIN MENU E 4 Select SENSOR DIAGNOSTICS ALARM LOG AGUATREND MENO E 5 Select DISPLAY STARTUP VALUES OTHER DEVICE MENU NETWORK MEHU These values are read when the instrument is first powered up so it is imperative the head is properly positioned on the body when power is applied Alternatively FEER these values can be re read by selecting ZERO ELECTRONICS from the calibration menu which is suggested before performing eithe
17. rie tds 38 4 5 Test Mode Mel viandas te uere eine e ai 38 4 5 E Mux Chal eet cete teet e Ee E AE EE EHE EE Eed Te tue dans 39 4 5 2 Amplifier Setting pios ROSEO ab eR gm pui adeps 39 45 3 Lamp Seu gx a ape ett e ose E e de Lp bb te Peel Las deducted eter de ic ariba 40 45 4 Millivolt Display urraca RAE n REPERI re e bp nies nae ies 40 SECTION 5 REPAIR AND UPGRADES 1 5 sess tenen entente tette tette tnnt 41 IL Introduction Het A Hed dier ere ed MI e RR NE aed tre ee ie Re ee ERR ds 41 5 2 Software Upgrade ciar titan dd eR RE dea eeu E edet ke ee e eet fare de 41 5 2 1 Determining the Software Version siontan ai aa nono enne nennen neret eene trennt a E E enne 41 5 2 2 Replacing the Flash Memory Chip csset eiee e aeea aaa aa a A ea e a aas 41 3 3 Circuit Board Replace mention id ig e eR rok cepe iem ie eels eed 44 5 3 T Circuit Board Removal iie d i eee Ute eoa ER ea oo vc et ee ento 44 5 3 2 Circuit Board Installation pts aede iet O te eodd Ret ue lec teg 46 5 4 Lamp Replacement iR oh e bea IER pice 47 XM PhOtocell Cle TEE 49 5 6 Photocell Assembly Replacement eeseeseeeeeeeeeeeeeee eene neret ona nono nr anar trennen restent eene nee e Ea 50 SECTION 6 REPLACEMENT PARIS osito scu eet eost eiie o eta oisi 55 Gacy SERVICE SECTION 1 INTRODUCTION 1 1 How to Use This Manual Read this introduction thoroughly to become familiar with the 1720D Low Range Process Turbidimeter pre repair
18. sheet 2 2 3 Cold Start Test 1 Press MENU on the AquaTrend Select SENSOR MENU 2 Press ENTER to select the 1720D 3 Select SENSOR DIAGNOSTICS followed by SENSOR COLD START 4 Select Yes when the display shows WARNING RESTORE DEFAULT SETTINGS MAIN MENU gt SENSOR MENU SENSOR MENU 7 P P ALARM LOs H 17280 TURE 1 1728p ALARM SETUP AGUATRE ND ME ML RECORDER SETUP SENSOR MENU MEASUREMENT OPTIONS OTHER DEYICE MENU SILENCE ALARMS NE TMWORK MEHU HOLD OUTPUTS H SENSOR DIAGNOSTICS P h 61 61 97 61 6197 SENSOR MENU SENSOR MENU E SENSOR MENU r 17200 TURBE 1_17200 B e SENSOR DIAGNOSTICS j WARNING RESTORE PLEASE WAIT PRINT TURE SETUP 3 DEFAULT SETTINGS CLEAR ALARM LOG E sEMSOR COLD START B res SENSOR RESET Ha LPELPTEEI CETLE TET CETE TET 5 After approximately 30 seconds the PLEASE WAIT message will clear from the AquaTrend screen 6 Press EXIT to return to the SENSOR MENU 20 SECTION 2 continued 7 Select CALIBRATION followed by CAL HISTORY 8 Ifthe calibration date time is 01 01 00 00 00 and the gain is 1 000 the Cold Start Test was successful 9 Press DISPLAY to return to the display mode 10 Record Pass or Fail for Step 3 of the checkout sheet 2 2 4 Portable AquaTrend Test 1 Plug the Portable AquaTrend into the remote connector of the 1720D 2 After approximately 30 seconds a reading will appear on Channel A of the Portable AquaTrend if the Portable AquaTrend Test was succe
19. so they do not touch the heatsink and place the head assembly top on the head assembly bottom Make sure the gasket Cat No 52028 00 is in place and no wires are pinched between the two halves Use locktight Cat No 41437 00 in the screw holes in the head assembly bottom place five screws in the holes and tighten To change the lamp Cat No 18950 00 perform the following steps When handling the bulb wear cotton gloves to protect your hands and to avoid fingerprints on the glass 1 Remove power from the 1720D Ensure the green power LED is not illuminated Remove the 1720D head from the body Turn the 1720D head over so the photocell faces up 47 SECTION 5 continued Disconnect the lamp leads by unplugging the connector After the bulb has cooled grasp the bulb with the fingers of one hand Twist the bulb in a counterclockwise direction pulling out slightly until the bulb is released from the housing Figure 9 Replacing the Lamp Assembly Head Assembly Bottom Cat No 52017 00 Screw 3 Places Cat No 52086 00 Lamp Assembly Cat No 18950 00 Optical Head Assembly Cat No 52179 00 Lamp Cable Cat No 52069 00 Gasket Cat No 52028 00 yz Ge A a ZZ pes LAMP Strain Relief Cat No 46696 00 Lock Nut Cat No 52060 00 DETECTOR NS l Strain Relief Cat No 52020 00 i Lock Nut Cat No 52060 00 10 ISSN SN
20. 00 bebes REUS 52017 00 Weider 52018 00 ere 52031 00 PNE 52032 00 Huan alas 52028 00 eedem 52051 00 OH 44114 00 44365 00 EE 52183 00 pipi 45667 00 delata 44153 00 LE 52100 00 AS 52157 00 ite 52157 10 eet 52157 25 mL e 52157 50 blauen 52157 51 ende a 52158 00 neis 52158 10 I 52158 25 Livre 52158 50 il 52158 51 hugs 52400 00 DET 44116 00 poet 52250 00 riada 52215 00 tia 52225 00 SECTION 6 continued Formazin Calibration Kit includes Description Unit Part Number Calibration Cylinder TenSette Pipet 4000 NTU Formazin Primary Standard 500 mL each 44156 00 Floor Stand for 1720D PS 1201 tp bre pee P te Ae EE each 52160 00 Mounting Kit pole wall for Portable AquaTrend sss each 51413 00 Photocell Replacement Kit for the 1720D essere re ren nennen each 52100 00 Pipet tips for 19700 01 TenSette Pipet c cecsccsssssecssscsesssesssscscsssssssssesssssseseeesssasseseessees 50 pkg 21856 96 Pipet tips for 19700 10 TenSette Pipet cscscesssesesssssscssssscesssssesessseesseasscscssseecssorsrersescees 50 pkg 21997 96 Portable AquaTrend nterface 4 c i acc t a See E aiii each andes 51400 00 Power Cord Kit 10A 125V 1 8 m 6 feet UL CSA listed eachais aimans 46306 00 Power Cord Kit 10A 230V 1 8 m 6 feet European style plug VDE approved
21. 000 PFD Ai 25 ADDRT ADDRH C12 3 68pF 0 01 28 LL 42 2 Au 4 ADORI TP40 0 01 35V TR5 50 VDC DRDY 7 Detector ats ee R 100 voe ZK 12 St 29 ADDRI4 1P32 4 Four VREF AD As La AOR us ci c2 VA J2 3 Detector Earth GND aser 2 LR 33 PFD 7N 33 PFD 2e 1 TPi3 TP9 TP O RESET c 3 vaer conv H v 29C512 ADDRIOO 151 ud E 100 VDC 100 VDC 057 1 enot c3 T 0 01 275 VAC R22 D 100 voc 16 CHGND 350 VDC TP62 T 68pF DGND TPB TRAN U P 177 ZERO OHM JUMPER 50 VDC va L x DS1233 Ea R24 45V 1 8W m L L LAMP lt 15 5V 02 TP3 BLACK m J1 1 Remote 12VDC 2 C21 c CB p t 100 5 pru Ok 1 gt 35 voc INES RB d vik SERVICK 35 VDC IQ 2 Remote GND 1 8W 1 49K 1 0 01 Lam p D rive N 1 8w 100 voc 4 6 NC Ji 3 REMOTE Service d 5 a P 5 N lt Remote Network E 07 95 gt B A D Converter 6j TP63 1N914 4N38 4 E LM358 err gt NETE J1 5 Remote Network R20 1 USA VV 1 0K 4x DSS306 2 _ mos VSN 1000 Pro tes Remote Eorth GND c19 1 8w swt FH C20 0 01 50 A La n c d 45V 12VF J1 11 5VDC 7 R2 100 voc E O O ld ev me A pal HEN A Ly 14 3K 1 06 Configure a a Hav 5 D5 1 88 4 2 TPE m A 41 10 GND 1N914 EP 1N914 pon PUSH BUTTON 1 4W NETA lt lt 1 7 Network al A C22 TP14 WE RIS 1 o TP2 100 EN eam neta lt a Network n RED SONG 100 VDC 100 voc 475K 1x KK aen Eorth GND 1 8W H3 5V TP58 Power Configure Status SEE REF REF DES GND 5V 5v
22. 1 20 98 Reworked units from 971000000101 to 980100000499 These reworked units 2 0 have 500 added to the original serial number 980100001000 1 20 98 Standard production with correct R23 value 2 0 990100004456 1 27 99 Production release with extensive feature improvements and additions 2 2 1 3 Software Version History Upgrade all 1720D instruments to the most recent version of software before returning the instrument to the customer The customer should also receive the most recent instrument manual version available Upgrade components are included in the 1720D Software Upgrade Kit Cat No 52183 00 Instructions for upgrading 1720D software versions are found in Section 5 2 on page 41 The following sections describe the new features contained in each release of 1720D software See the 7720D Instrument Manual Cat No 52000 18 for detailed information on each topic 1 3 Version 2 0 November 28 1997 Initial production release of 52146 79 1720D software 1 3 2 Version 2 2 January 27 1999 Production release with extensive feature improvements and additions SECTION 1 continued 1 4 General Service Information 1 5 Theory of Operation 1 5 1 Principle of Operation 1 5 2 Electronics Important Note Use only current revision parts and components Use of improper components may void compliance approval Repairing the 1720D Turbidimeter may involve replacing damaged optical components labels the turbidime
23. 20D sensor warnings that may be displayed are described in Section 4 2 5 1 through Section 4 2 5 5 When power is first applied to the 1720D a 60 second timeout timer is started to ensure the A D converter is functioning properly Every three seconds the a d converter is started and under normal operation completes its conversion cycle in 50 milliseconds When the a d converter completes its conversion cycle the timeout timer is reset to 60 seconds If the timeout timer expires indicating 34 SECTION 4 continued 4 2 5 2 Light Leak 4 2 5 3 Bad Lamp 20 consecutive a d conversion cycles did not complete the sensor warning A D TIMEOUT is added to the alarm log Since the 1720D cannot compute turbidity readings after an A D TIMEOUT dashes are displayed instead of turbidity values In addition the AquaTrend sensor alarm indicator is set denoted by a small box with a number in it at the bottom of the AquaTrend display Even after an A D TIMEOUT the 1720D continues to attempt to restart the a d every 3 seconds so that readings may be restored if the a d begins to work normally After an A D TIMEOUT cycle power to the instrument to ensure the a d converter is cleared When the 1720D starts the dark counts are read Dark counts are defined as the a d count values read at the photodetector with the lamp turned off Both low and high gain settings of the amplifier are read Later during normal reading mode the dark count va
24. 5 REMOVE DEVICE E LIST NETWORK DEVICES LIST METWORK DEVICES 17200 TURG f 172BD REPLACE DEVICE ALARM TO RELAY AGUATREND 1_MASTER version 2 6 ALARM TO RELAY RECORDER TO ANALOG OUT 17280 TURB 41 1728Dp E configured on line NETWORK MENU RECORDER TO ANALOG OUT SENSOR TO DISPLAY 17280 TURE 42_1720D H MO ERROR SEMSOR TO DISPLAY PRINT NETWORK IMAGE SIGMAL OUT 41 50M Reset Power up SINGLE SENSOR SYSTEM SERIAL I O 1_510 C More 3 E REVIEW MET CONNECTIONS pom d COM et et BEL REEF 61 8149 81 81 97 BEL REEF 5 2 2 Replacing the Flash Memory Chip To replace the flash memory chip in the 1720D 52000 00 perform the following steps 1 Record 1720D Sensor Settings a From the AquaTrend press MENU and select SENSOR MENU Select the sensor to be upgraded from the list Alternatively press the configure button on the sensor to be upgraded b Record each value from the menus listed in the table below 41 SECTION 5 continued MAIN MENU P ALARM LOG AQRUATREE ND MENJ SENSOR MEHU OTHER DEVICE MENU NETWORK MEHL AE SENSOR MENU SENSOR MENU SENSOR MENU E Ld Ll 17200 TURE 81 1728D 17200 TURE 81 1728D E 17200 TURE 41 172B8D CALIBRATION ALARM SETUP E BUBBLE REJECT on RECORDER SETUP SIGNAL AYG 38 Sec MEASUREMENT OPTIONS PRINT INTERVAL 1 Min SILENCE ALARMS TIME STAMP Or HOLD OUTPUTS More 3 BELREEF BET EEF Table 14 1720D Sensor Settings Menu Sensor Setting Value ALARM SETUP ALARM 1
25. 5 00 through bottom hole of optical head Make sure the outer shield drain wire of the cable is free from the hole Remove the red insulation sleeve from the spade lug Cat No 52073 00 and crimp it onto the shield wire Place spade lug between the flat washer and plastic and tighten the nut until just snug with a 7 16in wrench Do not over tighten On photocell stem place a flat washer Cat No 6959 12 a split washer Cat No 16185 00 and a hex nut Cat No 15585 00 Bend the spade lug 90 so it lays flat against the nut Place a 2 0 in length of heat shrink tubing Cat No 40707 00 over the photocell cable until it rests against the detector head Shrink the tubing with a heat gun Dress the cable so it lays between the lamp base mold feature and the inside edge of the optical head Cat No 52179 00 Pass the photocell assembly cable through strain relief marked DETECTOR leaving about 5 in protruding Tighten the strain relief Position the head assembly bottom next to the head assembly top Thread the black and red wire through the ferrite bead Cat No 52620 00 before installing the wires in the connector 23 Install photocell wires into connector J2 in the head assembly top according to Table 18 Table 18 Terminal Block J2 Wire Colors Position Wire Color Wire Source 1 Black Photocell 2 Red Photocell 3 Shield Photocell 24 Install the lamp wires into connect
26. 52000 04 Gach 1720D Low Range Process Turbidimeter SERVICE MANUAL Hach Company 1999 All rights reserved Printed in the U S A dd dp 12 99 1ed TABLE OF CONTENTS SERVICE 000 AA ete cn e He oe du A D eee eda 5 SECTION T INTRODUCTION oi cia di iig eb E Dao etl Fb c mea ott en hat Ln Ru 7 LET How to Use This Mariual 3 2 obedece nce 7 1 2 Serial N mbet History sce nete a cp en Eee ae da dagen hehe Lee tet eee ge euin ove ba eda ds 7 1 3 Software Version Hist d e tetendit ete tes e oce dee eee e eee dit 7 1 3 1 Version 2 0 November 28 1997 ed D aca tire rd eere eere reine Pape ee E ERE ERAN YET RENE 7 1 332 Version 2 2 Jan aty 27 1990 eid deed te UE E Ge a a eser b upto ota at Leda ped 7 1 4 General Service Informations ro ed e eee iet c gt e ce ita 8 Ls Theory of Operation s t ede A Le dise ip et E eR Reed 8 1 5 1 Principle of Operation ite eed eR ete et dt e tee ge iiio 8 1 522 BIeCtfODICS i on neo ade i E ee PEE SIS E Eee HV Ce Eee E A EE ERR eoe dd 8 1 5 2 Amplifier et NON 9 1 3 2 2 System Voltage Divide deb een Ps 10 1 5 2 3 A D ConYVeTIer oc use eee eee e tree te er iia 11 1 5 2 4 Microprocessor and Memory dam dr t nm lote eee te eet ep iia 11 LO Network Interface vison 5 ione ee eco etna i Rie ERR 11 1 6 1 23 Volt G nerator ves 1 2 Ee ue ar Fed dert eee Pa e e reote pesce pe e Fiet oe beer be eeu 12 1 6 2 Camp Diver ses uite Np octo Spleens b UE vei ine Nea ios 12 1 6 3 Co
27. 6 A Y 2N3904 dL RUN A o A TP47 D4 C16 R3 af E ue E BAV99LTI BAV99LTI BAVSSEH o 10K 1 ial i E gt nera 100 VDC 1 8W H c9 oe 1 f J z Bypass Caps A A Uk TP50 E m R21 R9 He TBBI 5v 001 1 10K 1 TP53 O 1000 VDC 50 VDC wt LONN 475K 1 1 8W u10 5v 402 OHM 1 wil B 1 8W c29 TP55 a ne Ht Oo SEE NOTE ON 177 A de PAGE 2 en 03 2 SEDET 35 VDC icap osc H 15 5 oot asu FOR UN J R10 SPDT 30 9K 1 ICL 7660 c30 RI DU ADEE O un ee 50 vie ew TP52 a E y ok NET LA S 2Ne s 10K 1 Ti NET B 6 5 Generator ys ae a 2 fe 1P18 RX_ACTIVE 1 R5 d 9 eser Network Interface po 10K 1 u12 g J CLKSELO ICL7650 1 8W L C15 6264A ADDREOO 151 U5 4 SLKSELI T 04 ADDRIO0 151 TP38 ABDRUG A ADDR D Ge 38 7 TXEN csi e D re am 50 VDC nc H ADDRO 63 cro 28 REY p 2 ADDRI2 A ADDRI2 TP33 at cPt TP56 001 72 ami T e TP39 ADDRO2 A ADDRO2 62 CP2 E FTT 10 1000 voc Mt Fr nR ADDROS 6f 3 TP19 A10 PETHE EE ADDR TP42 45V TP37 ADDRO4 A ADDRO4 60 he Et 32 ET t 25 ADDROB A ADOROB TP41 OS 22 15 O N W 3 ADDRO7 TP A lag Ae 4 ADDROS_ A ADDROS TP35 TP64 2 OIT AT 100 2 0 40 AS 5 ADDROS 12 VADDROB 56 ag 101 D C AB FAR ADDROS 55 4 D CON 6 ADDRO4 1 1 ADDRIS inns ni AD 102 AS 7 ADDROS U6D 13 ADDRIO 54 o 103 D_CAL TP31 as 2A U6A appara ADORTI 53 10 STATU TP4 DATA7 DATA7 19 1 08 A2 B ADDRO2 2 ADDRI2 52 Att 104 tT A AST TP29 paras DATAS 7 1 07 A Da ADDED 1
28. 68 74HC00 ADDRIS 51 We E 12 1 AME ON eno paras 16 1106 AQ 74HC00 ps ADDR 4 50 Ala 107 13 IN TP27 batas ADATAS 5 o eso 28 TP56 ADORIS 47 Juss 108 P A n tik DATA2 15 wr 127 109 DATA ADATA 12 jos El 6 Tp24 ATAO M DATAO 43 ty joto 5 4 n usa E DATAO 11 ae 20 ADDRIS 45V ra ll yu 0 01 TP25 Mot tsi p 3 O DATA2 DATA2 38 PI DATAS 37 TRIS Oo c6 100 VDC 74F32 2 TP26 paras Aatas 38 po R16 TP57 1071 T 1 Bl k PBo usc TP DATAS 35 TPI6 1 8w lo ermina OCKS 10 28 1 D5 TP67 DATAG A DATAS 34 e 10K 1 TP74 9 DATA 3 24 1 8w 14 i TP69 ui n T TP30 DATAZ 33 crocki 22 TE 32 768 KHZ u2C DATALO 71 CLOCK2 R6 D8 FL5 22 10 i R W SERVICE H cto MEE NP D9 1N914 LAMPS E 48 UE D 0 01 E lt J3 1 24 E RESET XIN Y2 Lamp DE St 74F32 100K 1 100 VDC XTAL A Y 2800236 E TP21 MC143150 1 10W T CS5504 8P TP73 A 12 ADDROO a 1N914 43 2 Lamp Pr 1 ADORO appRo TP43 M M R7 Q ri TP75 DATAD 43 froo 43 10 ADDROZ icroprocessor NMemory 475 1 rs nore 1000 PFO pataco 77 DATAT 14 o ADORO A aopRos TP45 1 10W pm s DATA2 15 0 hi 8 ADDROA 45V B e 50 VDC TP70 DATAS 17 ven At 7 ADDR ADDROS 187 ap UP ibn C39 DATAS Te 704 ae ADORO amo 76 O v Yi 100 VDC poi Bat TPI2 gout Fla DATAS 20 05 7 27 ADDROB IP34 XTAL E Lt 7 AINZ sek E lt 1 42 1 DATAT 21 oS A8 26 ADDROS ADDROS 5 0 MHZ 8 H TANI 7 Dss306 a Detector Ae osama T Tp RENE Ui AN2 SDATA 1
29. Configure LED Troubleshooting Table Symptom Possible Cause Corrective Action Flashing steady once per second Unconfigured from the factory Normal state before the device is added by the AquaTrend Add device from the AquaTrend NETWORK menu Manually unconfigured configure button held down during power up Replace device with itself from the AquaTrend NETWORK menu Normal operational state after the device is added Configured by the AquaTrend Steady off Configured but master AquaTrend was replaced pee ee toe NET CONNECTIONS se echon from Aqua Trend NETWORK menu Steady on No Application Device checksum failure Replace circuit board Erratically flashing Unknown Check power supply connections Replace circuit board 3 2 6 Status Indicator The yellow Status Indicator blinks once every three seconds corresponding to when a measurement is taken in normal operation The Status Indicator lights steady when the sensor is in an alarm condition or when a malfunction has prevented instrument operation Alarms associated with a specific sensor and additional pertinent information are shown in the alarm log Table 11 Status LED Troubleshooting Table Symptom Possible Cause Corrective Action Status LED always OFF not blinking every 3 seconds A D converter circuit failure Look for A D Timeout in sensor alarm log Cycle power to instrument Replace c
30. D will begin to flash indicating the 1720D is ready to be added to the AquaTrend network If the 1720D was inadvertently manually unconfigured it can easily be re added to the AquaTrend by using REPLACE DEVICE from the NETWORK menu See the AquaTrend Interface Manual Cat No 51350 18 for more information 31 32 SECTION 4 DIAGNOSTICS The 1720D contains built in diagnostics that are run at power up and in the background In addition service menus that allow additional diagnostics to be examined can be enabled via the AquaTrend 4 1 Neuron Chip Diagnostics After reset the Neuron chip automatically performs the following tasks e Application Checksum Verification e System Checksum Verification RAM Test If any of these tests fail the node will automatically go applicationless and the Configure LED will light steady When this occurs the Neuron will not run its application program The result of these tests are stored in the Neuron Error Log which is accessed via the Device Status command See the AquaTrend Service Manual Cat No 51350 04 for more information on device status 4 2 Sensor Alarm Log The alarm log is used to show sensor warnings and alarm conditions for the AquaTrend and each attached sensor An alarm indicator shown as a number from 1 8 denoting sensor alarms or as an N denoting network alarms appears along the lower portion of the AquaTrend display during an alarm condition 4 2 1 Reviewing th
31. ED ON THIS DWG THE DIAGRAMS BELOW SHOW THE FTT 10 AND FTT 10A WITH PIN NUMBERS AND PIN NAMES T2 GND T T2 GND TI 13 12 1 8 8 7 vcc O O O 18 O 10 CLK VCC o O O O O CLK RX ACT O O 2 RESET CLKSELO O Ol 8 CLKSEL1 TXD TXEN O O 7 RXD O RXD FTT 10 FTT 10A NET B O O 6 NET A NET B 2 O O NET_A QUANITITY PER SUEF X DESCRIPTION TE net PART NO ITEM PARTS LIST FOR GENERAL REQUIREMENTS NOTICE Hach Company claims proprietary rights in the information on this drawing It is issued in confidence SEE HACH STANDARDS DIMENSIONS ARE IN INCHES for engineering information only ond moy not whole or in port be used to manufacture anything whether or not shown hereon reproduced or disclosed to onyone without direct written permission from Hoch Compony DO NOT SCALE THIS DWG DWN 8 25 97 KBS MATL cH C HACH HACH COMPANY LOVELAND COLORADO AMES IOWA nne SCHEMATIC PE m 1720D PROCESS TURBIDIMETER SHT SIZE REV SIZE DWG NO REV REVISION STATUS penance n OF i SHEETS NEXT ASSY USED ON SCALE su 20F2 C 32000 98 A
32. Figure 3 Voltage Measurements TP1 Black SRT gt LEDI ER mag Suis e MEE E C2 ED3 ung 02 C3 C13 rei 3 3 Troubleshooting Procedures 3 3 1 Cold Start MAIN MENU P ALARM LOG AGUATREND MENU EH SENSOR MENU OTHER DEVICE MENU NETWORK MENU CETE TET The following procedures describe techniques used in the troubleshooting tables During the Cold Start procedure the instrument erases and reprograms appropriate memory The following device settings are replaced with the instrument default settings e Calibrations and calibration standard values e Settings for measurement options Alarm levels recorder min max e Sensor name Network connections are NOT affected by the cold start procedure Perform a cold start as follows 1 Press the MENU key to access the MAIN MENU 2 Select SENSOR MENU and press the ENTER key 3 Select the sensor to be cold started and press the ENTER key 4 Select SENSOR DIAGNOSTICS from the Sensor Menu and press the ENTER key 30 SECTION 3 continued SENSOR MENU SENSOR MENU 5 Move the pointer to SENSOR COLD START and press the ENTER key 6 The display will show WARNING RESTORE DEFAULT SETTINGS Select YES and press ENTER to accept 7 Press the DISPLAY key to return to display mode At this point the instrument will display turbidity readings based on a pre programmed calibration curve However the instrument must be recalibrated to meet th
33. LonWorks systems Two numeric turbidity output SNVTs Standard Network Variable Types allow the 1720D to communicate with virtually any SCADA system that provides a LonWorks driver In addition all setup parameters measurement options alarm setpoints recorder min max etc can be accessed via SNVTs 17 SECTION 1 continued 1 8 Required Tools and Equipment A list of common tasks and associated tools for repairing the 1720D is shown below Checkout Sheet PS1201 Power Supply AquaTrend Calibration Cylinder StablCal Standards 0 1 1 20 NTU 1720D Head Disassembly 2 Phillips Screwdriver Circuit Board Replacement 2 Phillips Screwdriver 1 8 Tip Slotted Screwdriver Software Upgrade 2 Phillips Screwdriver PLCC Extraction Tool Cat No 30484 00 Photocell Replacement 2 Phillips Screwdriver g inch Tip Slotted Screwdriver Crimping Tool 7 16 inch Open End Wrench Heat Gun Lamp Replacement Cotton gloves Circuit Board Voltage Test 2 Phillips Screwdriver Digital Volt Meter DVM Digital Oscilloscope optional 18 SECTION 2 2 1 Test Method INSTRUMENT INSPECTION AND CHECKOUT Do not use any test equipment that is overdue for calibration Observe all electrostatic discharge E S D requirements Pay attention to all warnings in this section failure to do so could result in serious personal injury or damage to the instrument In this section the term instrument refers to Ca
34. MEHU SENSOR MENU E SENSOR MENU The zero electronics procedure and calibration history are described in the following sections Before starting a calibration the electronics should be zeroed to compensate for any optical or electrical offsets A detailed procedure for zeroing the electronics is presented in the 1720D instruction manual and Zero Electronics is automatically performed each time power is applied to the 1720D When zeroing the electronics ensure the 1720D head is properly seated on the calibration cylinder or turbidimeter body and select ZERO ELECTRONICS from the sensor calibration menu This step establishes a zero light offset which is subtracted from all future readings During the zero electronics procedure the lamp is turned off and the system volts as well as high low gain detector values dark values are read Once this procedure is complete the lamp is turned back on and the PLEASE WAIT message is removed from the AquaTrend display Do not remove the 1720D head during this procedure or incorrect offset values will be read Performing Zero Electronics is equivalent to pressing the SYS RESET key on the 1720C turbidimeter h k r r Press DISPLAY To Show Data SELECT SENSOR 17280 TURBE 41 1728Dp ALARM LOG E 17280 TURE 41 1728D CAL IBRATI N AGUATREND MENU ALARM SETUP El SENSOR MENU RECORDER SETUP SENSOR MENU E SENSOR MENU SENSOR MENU 172860 TURE 4i 172H8Dp OTHER DEVICE MENU MEASUREMENT OPTIO
35. N Lamp Socket Cat No 4404 26 Pull the lamp leads and connector through the hole in the lamp housing Pull the lamp leads and connector of the new lamp through the hole in the opposite direction of step 5 Rotate the new lamp so that the three alignment pins line up Pressing slightly twist the lamp in a clockwise direction until the alignment pins are fully seated Plug the lamp lead connector into the mating connector on the 1720D head Place the 1720D head on the body and restore power to 1720D After approximately 30 seconds remove the head and ensure the lamp is on 48 SECTION 5 continued Figure 10 Lamp Assembly Lamp Housing 5 5 Photocell Cleaning Note Do not scratch the photocell window 11 The lamp has been burned in at the factory before being shipped and is ready for use 12 Calibrate the 1720D per the instrument manual Occasional clearing of the photocell window is required The frequency of the cleaning will depend on the nature and concentration of dissolved and suspended solids in the sample Biological activity contributes to mineral scale deposit on the window In general more growth will occur in warm temperatures and less in cold Inspect the photocell windows often to determine cleaning needs Remove any organic growth or film on the photocell window before standardization or calibration Use a cotton swab and isopropyl alcohol or a mild detergent such
36. NS NETWORK MENU SILENCE ALARMS HOLD OUTPUTS Ca MORE 7 61 61 97 P CALIBRATION ZERO ELECTR NICS PLEASE WAIT NORMAL CAL PLACE TURG HERD N COMPARATIVE CAL CAL CYLINDER E ZERO ELECTRONICS 1 7 4 2 Normal Calibration CAL HISTORY H continue PRINT CAL HISTORY Return CETE TEK Normal calibration is performed with the standard Formazin based calibration sequence During this procedure both a DI water and a known Formazin standard value typically 20 NTU are read in a calibration cylinder Signal averaging is automatically set to 6 seconds during this procedure and restored to its pre calibration setting when calibration is complete See Calibration in the 1720D Instrument Manual Cat No 52000 18 for detailed information on performing the normal calibration procedure 15 SECTION 1 continued 1 7 4 3 Comparative Calibration 1 7 4 4 Calibration History Comparative calibration is an alternate calibration method In this method the 1720D is forced to read the same value as a grab sample from a laboratory turbidimeter As in normal calibration signal averaging is automatically set to 6 seconds during this procedure and restored to its pre calibration setting after calibration See Calibration in the 1720D Instrument Manual Cat No 52000 18 for detailed information on performing a comparative calibration procedure A history of either calibration type is displayed by selecting CAL HISTORY from the calibration menu
37. Negative readings Light leak 1720D head not on body or calibration cylinder during Power Up or Zero Electronics Ensure the 1720D head is on the body and properly aligned Repower instrument or perform ZERO ELECTRONICS in the calibration menu Lamp burned out aged lamp or corroded lamp terminals Check lamp connector Replace lamp Check lamp connection at circuit board Improper calibration Check CAL HISTORY menu for bad gain Check calibration standards Recalibrate instrument Dirty optics Clean optical components photocell lamp lens Photocell cracked disconnected Check photocell wiring at circuit board Replace photocell Bad lamp driver circuit Check lamp voltage Check 12V and 5V voltages red and orange wires Replace circuit board 25 SECTION 3 continued Table 6 Overrange Troubleshooting Table Symptom Possible Cause Corrective Action High readings Continuous overrange 100 NTU displayed Dirty optics Clean the optics photcell lamp lens Flow rate greater than 750 mL min Check flow rate DI water turbidity greater than 0 5 NTU Check calibration standards and recalibrate the instrument Improper calibration Check CAL HISTORY menu for bad gain Check calibration standards Recalibrate instrument Shade broken off photocell assembly Replace shade Aperture cracked broken or dirty Repl
38. TYPE ALARM SETUP ALARM 1 HYSTERESIS ALARM SETUP ALARM 1 SET POINT ALARM SETUP ALARM 2 TYPE ALARM SETUP ALARM 2 HYSTERESIS ALARM SETUP ALARM 2 SET POINT RECORDER SETUP RECORDER 1 MIN RECORDER SETUP RECORDER 1 MAX RECORDER SETUP RECORDER 2 MIN RECORDER SETUP RECORDER 2 MAX MEASUREMENT OPTIONS BUBBLE REJECT MEASUREMENT OPTIONS SIGNAL AVG MEASUREMENT OPTIONS PRINT INTERVAL MEASUREMENT OPTIONS TIME STAMP EDIT NAME SENSOR NAME 2 Change the 1720D Flash Memory Chip Important Note This procedure sets calibration and measurement option information to their default values a Remove power to the 1720D Ensure the green power LED is not illuminated Remove the 1720D head from the body Remove the 5 Phillips screws from the underside of the 1720D head Separate the top half from the bottom half of the 1720D head exposing the circuit board Locate socket U1 on the 1720D circuit board Remove the flash memory chip from the socket by placing the metal teeth of the PLCC extraction tool in the slotted corners of the socket Gently squeeze the extraction tool to close around the memory chip As you squeeze the teeth of the extraction tool will pull the memory chip from the socket 42 SECTION 5 continued Figure 4 Flash Memory Chip Location HI a CS5504 BP GNARMC9746 f Obtain the latest 1720D software upgrade kit Cat No 52183 00
39. ace or clean aperture Overvoltaged lamp Ensure head cable has not been shortened Check lamp voltage Replace head cable and lamp Replace circuit board 3 2 2 Zero or Erratic Readings If the instrument is improperly calibrated or damaged readings may display as Zero or fluctuate erratically Table 7 Zero or Erratic Reading Troubleshooting Table Symptom Possible Cause Corrective Action Always reads zero Lamp unplugged burned out or old lamp Check lamp connector Replace lamp Check lamp wires at circuit board Improper calibration Check CAL HISTORY menu for bad gain Check calibration standards Recalibrate instrument Dirty optics Clean optical components photocell lamp lens Photocell cracked disconnected Check photocell wiring at circuit board Replace photocell Bad 12V red wire 5V orange wire or ground black wire connection Check red black and orange connections at power supply and on circuit board Erratic readings Photocell cracked disconnected Check photocell wiring at circuit board Replace photocell Bad 12V red wire 5V orange wire or ground black wire connection Check red black and orange connections at power supply and on circuit board Dashes displayed Network wires disconnected or shorted Reconnect green and white network wires Check for pinched or shorted network wires A D
40. alculated by the microprocessor inside the 1720D head and readings are sent via the network to the AquaTrend Interface where the data is displayed and stored for trending purposes Readings are sent to peripheral devices as well These peripheral devices include Signal Output Modules SOM which provide two relay and recorder outputs Serial I O Modules SIO which provide two way communication with a personal computer or printer and a Digital Display Module DDM which provides an eight character LED local display A Portable AquaTrend can also be plugged directly into the 1720D head allowing local calibrations and other setup functions to be performed The 1720D electronics consist of 10 major sections These are the amplifier system voltage divider A D converter microprocessor and memory network interface 5V generator lamp driver configure button portable AquaTrend interface and LEDs SECTION 1 continued Figure 1 1720D Turbidimeter Components Turbidimeter Head Turbidimeter Body 1 5 2 1 Amplifier The amplifier section consists of an ICL7650 chopper stabilized op amp in a T Network transimpedance configuration In addition the contacts of a relay are connected across one of the resistors in the T Network With the relay contact open the gain of this amplifier is given by v open 475k 1 AM 15 152 500 E 1K A Similarly with the relay contact closed the gain of this amplifier is V closed
41. as Liqui nox to remove most sediment and dirt Mineral scale buildup may require cleaning with a mild acid applied with a cotton swab followed by a detergent wash Do not use abrasive cleaners 49 SECTION 5 continued 5 6 Photocell Assembly Replacement To replace the photocell assembly Cat No 52180 00 perform the following steps 1 Remove power from the PS1201 Power Supply that is connected to the 1720D Turbidimeter head assembly Ensure the POWER LED on the 1720D head is not lit Note Perform all assembly and disassembly at an EDS work station while wearing a grounding strap to avoid damage to the circuit board 2 Remove the 1720D head from the turbidimeter body Turn the 1720D head over so the photocell faces up 3 Remove the five Phillips head screws Cat No 5587 11 from the perimeter of the turbidimeter head assembly 4 Separate the turbidimeter head assembly into two parts The top Cat No 52018 00 contains the circuit board and the cable connected to the PS1201 The bottom Cat No 52017 00 contains the photocell and lamp 5 Loosen the three screws holding each wire in J2 and remove each wire Retain the ferrite bead for use in reassembly See Figure 11 6 Loosen the two screws holding each wire in J3 and remove each wire Figure 11 Head Assembly Top J2 i To Photocell Assembly l To Lamp e e Ss 50 SECTION 5 continued Figur
42. cribed in the Calibration section of the 1720D Low Range Process Turbidimeter Instrument Manual 2 Record the value next to GAIN in the first CAL HISTORY screen for Step 10 of the checkout sheet If the number is between 0 750 to 1 50 the test was successful 22 SECTION 2 continued 2 2 8 One 1 0 NTU Test 2 2 9 Remove Device Test Perform the Calibration Curve Verification procedure described in the Calibration section of the 720D Low Range Process Turbidimeter Instrument Manual This verification may be performed in a calibration cylinder if a 1720D body is not available Because of the large dilution factor use only 1 0 NTU StablCal standard Cat No 26598 53 for this test Do not attempt to make 1 NTU formazin from a 4000 NTU standard Record the value from the test for Step 11 of the checkout sheet If the number 1s between 0 95 and 1 05 NTU the test was successful Press MENU on the AquaTrend Select NETWORK MENU followed by REMOVE DEVICE Select SENSOR Press ENTER to confirm removal of the 1720D Wait approximately 10 seconds If the OPERATION COMPLETE screen appears and the configure LED begins flashing once per second the Remove Device Test was successful Record Pass or Fail for Step 12 of the checkout sheet Unhook the 1720D from the PS1201 AquaTrend Place a copy of the 1720D checkout sheet into the packing carton with the instrument 23 24 SECTION 3 3 1 Introduction TROUBLESHOOTING
43. cte n R o A sere SEC pe nee decet 19 2 2 2 Add Device h 2 EE Re DC ee Pe Pa o ER iei Pete lbn 20 2 23 Cold Start eSt tmt ERE Ren teste rete o Nata hive reste bae as fed 20 2 2 4 Portable Aqua Trend Test io Se cue been ete Lee Laeti de De eee epe e aes 21 2 2 5 Sensor Startup Valles stetit er etu etie n eC etie Reti Ce PU PER E RAT 21 2 2 0 Calibration DD Water Test ER eee PRA e main ohne EE ena edere epe tesa 22 2 27 Calibration Gain Factor s e oot Gazeta eee a a pereo tanen est A ea De aree hose eee ipee bn 22 2 2 8 One 1 0 NTU eStore ia coeds tate cete rea eee tec ee tede deba ai 23 2 2 9 Remove Device T6st e e rit E E NR E lae e e D NE RAE seats detuned cameo de ERR note 23 TABLE OF CONTENTS continued SECTION 3 TROUBLESHOOTING tirithrmasir te eH ope Heo cisco beg bein beb bed eb bi Fere voa i edscbgbs 25 SD Introduction eee aem e e a ERASMI retine da 25 3 2 Troubleshooting Lables iet ds eoe eee eue ree eere 25 3 2 1 Undetrrange OVerrange eiie epe eiit etc e pie a e e HE ee bc idee E ELE nte eet repere ee o edenda 25 3 2 2 Zero or Erratic Readings uid A a eene e eee is 26 3 2 3 Questionable Cali i nte ett ederet estet tees cc P ence teh cette datos ere cet ica 27 2 2 Power Indicator ion RNA 27 3 2 Configure LED il ste nek A a ee deter med de ape es 28 3 2 6 Status Indicator c eoe A a eee recente obese ES 28 3 2 7 Alarm Log Sensor Warnings eae diee rt pe ipee Dee ge Leon dene 28 3 2
44. d in the alarm log The typical voltage drop on the 5 system voltage with a good lamp is 15000 a d counts 71 5 millivolts Besides a burned out lamp BAD LAMP may indicate the lamp is unplugged either at the connector outside the 1720D head or at the circuit board the lamp circuit failed or overheated on the circuit board or there is a problem with the power supply 35 SECTION 4 continued 4 2 5 4 System Volts 4 2 5 5 Low Signal The same lamp on volts 5 system voltage with lamp on that are used to check for a bad lamp are checked absolutely against 65535 a d counts 5 469 volts If the voltage is greater than 5 469 volts the supply is considered out of range and SYSTEM VOLTS is stored in the alarm log and the AquaTrend sensor alarm indicator is set denoted by a small box with a number in it at the bottom of the AquaTrend display The 1720D attempts to continue reading turbidity even after SYSTEM VOLTS is stored in the alarm log A SYSTEM VOLTS error may indicate a problem with power supply a head cable that has been cut too short or a problem with the 1720D circuit board When the amplifier is set to high gain x32 each A D reading is compared to the high gain dark value If the reading is less darker than the high gain dark value LOW SIGNAL is stored in the alarm log and the AquaTrend sensor alarm indicator is set denoted by a small box with a number in it at the bottom of the AquaTrend display
45. e Table 15 Terminal Block J1 Wire Colors Position Wire Color Wire Source 1 Brown Remote Connector 2 Black Remote Connector 3 Blue Remote Connector 4 Gray Remote Connector 5 White Remote Connector 6 Green Yellow Remote Connector Ground Lug 7 White 52019 00 Head Cable 8 Green 52019 00 Head Cable 46 SECTION 5 continued Table 15 Terminal Block J1 Wire Colors Continued Red 52019 00 Head Cable 10 Black 52019 00 Head Cable 11 Orange 52019 00 Head Cable 12 Shield 52019 00 Head Cable 5 4 Lamp Replacement Position the head assembly bottom Cat No 52017 00 next to the head assembly top Cat No 52018 00 Thread the black and red wire from the photocell through the ferrite bead Cat No 52620 00 before installing the wires in the connector Install photocell wires into connector J2 in the head assembly top according to the following table Table 16 Terminal Block J2 Wire Colors Position Wire Color Wire Source 1 Black Photocell Red Photocell Shield Photocell Install the lamp wires into connector J3 in the head assembly top according to the following table Table 17 Terminal Block J3 Wire Colors Position Wire Color Wire Source 1 Black Lamp 2 Red Lamp 10 Place five washers Cat No 6956 12 on five Phillips screws Cat No 5587 11 Route all wires
46. e 12 Head Assembly Bottom 7 Hold the bottom of the head assembly so the photocell is facing up Loosen the strain relief marked DETECTOR See Figure 12 8 Cut the photocell cable Y in back from the spade lug and Y in back from the DETECTOR strain relief Head Assembly Bottom Lamp Cable Cat No 52069 00 Gasket Cat No 52028 00 Cat No 52017 00 re ZILLI VIII m d ZA A LA H cance aes Screw 3 Places Cat No 52086 00 Lamp Assembly Cat No 18950 00 Optical Head Assembly Cat No 52179 00 M 3 i SSS LAMP Y Strain Relief Cat No 46696 00 Lock Nut Cat No 52060 00 NN E mn LDL DETECTOR Strain Relief Cat No 52020 00 Lock Nut Cat No 52060 00 Sy NN SY SN Lamp Socket Cat No 4404 26 9 Pull the photocell wire out of the strain relief 10 Remove the heat shrink tubing on the photocell stem to expose the nut holding the photocell onto the assembly 11 Using a 7 16in wrench turn the nut counterclockwise several turns 12 Remove the spade lug from the stem and cut the wire attached to the photocell 13 Remove the nut flat washer and lock washer from the photocell stem 14 Pull the photocell assembly away from the lamp removing the assembly from the cap bottom 51 SECTION 5 continued 20 21 22 Feed the wires and stem of the replacement photocell assembly Cat No 5200
47. e 7 Lift the circuit board Cat No 52031 00 out of the head assembly top Cat No 52018 00 Figure 6 Removing Wires 0 e e 6 C a Ee n 6 gt Figure 7 Removing Screws from Circuit Board Circuit Board Cat No 52031 00 Remove screws Cat No 7511 11 2 Places 45 SECTION 5 continued 5 3 22 Circuit Board Installation 1 Feed the head cable wires Cat No 52019 00 through the large hole in the 52031 00 circuit board and place the board in the head assembly top so that circuit board components face the open end of the head assembly and the flat end of circuit board faces the flat end of the head assembly To ensure proper push button operation hold the circuit board tight against the flat end of the head assembly Make sure the wires to the remote connector are not trapped beneath the circuit board 2 Place two Phillips screws Cat No 7511 11 in holes and tighten Figure 8 Head Cap Top and Bottom Head Cap Top Cat No 52018 00 Gasket Cat No 52028 00 Washer 5 Places Cat No 6956 12 Screw 5 Places Cat No 5587 11 Head Cap Bottom Cat No 52017 00 3 Install the wires in terminal block J1 according to the following tabl
48. e Sensor Alarm Log To review the entries in the 1720D alarm log perform the following steps 1 Press the MENU key to access the MAIN MENU Move the pointer to ALARM LOG and press the ENTER key 2 Select the appropriate sensor 1 8 and press the ENTER key 3 Alist of the 1720D alarm log entries is displayed For more information about a particular alarm log entry select the entry of interest and press the ENTER key MAIN MENU ALARM LOG E ALARM LOG E r ALARM LOG N NETWORK AND AGUATREND POWER UP 81 81 97 B jDESCc POWER UP AGUATREND MENU E 1 17280 Ture 1 1728D RL2 END 81 81 37 B DATE 61701797 68 88 SENSOR MENU ALL END 81 81 87 OTHER DEVICE MENU AL2 BEGIN 81 81 97 NETWORK MENU AL BEGIN 81 81 97 AL ENC B1 817 37 Ca Hore EEES EEES EE THE DHTPITLE ALARM LOG Up to 14 entries can be stored in each 1720D sensor alarm log The most recent entry is shown at the top of the list If more than 14 entries are stored the newest entry will appear at the top of the list and the oldest entry will be deleted Any active sensor warnings are automatically acknowledged the number is removed from the lower portion of the screen when the sensor alarm log is first displayed 33 SECTION 4 continued 4 2 2 Alarm Begin ALARM LOG j DESC ALARM 2 SET POINT 166 8 VALUE 166 8 DATE 81 81 97 86 68 61 6149 SET POINT 166 6 32 88 81 81 37 86 68 AE 4 2 4 Power Up ALARM LOG j DESC POWER UP
49. e accuracy specifications A cal history date and time of 00 00 00 00 00 and gain setting of 1 0 indicates the pre programmed calibration is in effect E SENSOR MENU E SENSOR MENU r r SELECT SENSOR 17200 TURPE 4i 172B8Dp i728p TURE 4i 1728Dp m E 17200 TURE 1 172B8D ALARM SETUP SENSOR DIAGNOSTICS PLEASE WAIT RECORDER SETUP PRINT TURE SETUP MEASUREMENT OPTIONS CLEAR ALARM LOG SILENCE ALARMS E sEMSOR COLD START HOLD OUTPUTS SENSOR RESET SENSOR DIAGNOSTICS More CETE TET CE TLE TET CEDE TEK irira 3 3 2 Manually Unconfiguring the 1720D Use this procedure only if the AquaTrend will not remove the 1720D using REMOVE DEVICE from the NETWORK menu or if the AquaTrend that installed the 1720D is not available The manual unconfigure procedure does NOT change the following settings e Calibrations and calibration standard values e Settings for Measurement Options e Alarm levels recorder min max e Sensor name Warning Network connections between the 1720D and the AquaTrend DDM SOM and SIO are removed by this procedure The 1720D network can be manually removed from the AquaTrend and all network applied parameters erased with the following procedure 1 Remove power from the 1720D and ensure the green Power LED is off 2 Press and hold the configure button on the 1720D head 3 While holding the configure button down restore power to the 1720D 4 Release the configure button after 10 seconds The configure LE
50. eckout sheet Lamp Off 5V Millivolts Test 1 Note the value displayed next to LAMP OFF 5V If the number is 4700 to 5700 the Lamp Off 5V Millivolts Test was successful 2 Record Pass or Fail for Step 7 of the checkout sheet Lamp On 5V Millivolts Test 1 Note the value displayed next to LAMP ON 5V If the number is 225 to 275 lower than lamp off the Lamp On 5V Millivolts Test was successful 2 Record Pass or Fail for Step 8 of the checkout sheet 2 2 6 Calibration DI Water Test SENSOR MENU TYPE NORMAL CAL ATE 6181 97 86 68 DI WATER 4 144 NTU CAL STG 2H HH NTU GAIN 8 957 ERROR NONE B1 B1 37 2 2 7 Calibration Gain Factor 1 Perform a user prepared calibration called Normal Calibration in software version 2 0 as described in the Calibration section of the 720D Low Range Process Turbidimeter Instrument Manual Note Be sure to use low turbidity filtered deionized water 2 View the first CAL HISTORY screen 3 Record the value of the DI water In software version 2 0 this is the number next to DI WATER In software version 2 2 and higher this is the first number on the CAL STD line If the value of the DI water is less than 0 25 NTU the test was successful Perform a normal calibration as described in the Calibration section of the 1720D Low Range Process Turbidimeter Instrument Manual 1 Perform a user prepared calibration called Normal Calibration in software version 2 0 as des
51. ents section for more information 40 SECTION 5 REPAIR AND UPGRADES 5 1 Introduction This section contains information on common repair and upgrade procedures Important Note Wear a grounding strap when touching any of the circuit board components 5 2 Software Upgrade The 1720D software resides in Flash memory a rewritable memory type similar to EEPROM Electrical Erasable Programmable Read Only Memory Because the memory is rewritable the software can be updated in one of two ways by replacing the chip or by downloading over the LonWorks network Currently only chip replacement is supported 5 2 1 Determining the Software Version Determine the software version of any device on the network from the AquaTrend Interface by performing the following steps 1 Press the MENU key to display the MAIN MENU d MAIN MEHU E 2 Select NETWORK MENU ALARM LOG AQUATREND MENU SENSOR MENU 3 Select REVIEW NET CONNECTIONS OTHER DEVICE MENU NETWORK MENU 4 Select LIST NETWORK DEVICES B1 B1 97 5 Select the appropriate device and press ENTER The type of device and name is shown on the first line 1720D TURB 2_1720D in this example The software version is shown on the second line version 2 0 in this example See the AquaTrend Interface Manual Cat No 51350 18 for more information on listing network devices P P NETWORK MENU NETWORK MENU NETWORK MENU ADD CEWICE REVIEW MET CONNECTIONS REVIEW MET CONNECTIONS
52. ircuit board Circuit board failure Ensure green power LED is illuminated Check red black and orange connections at power supply and on circuit board Replace circuit board Status LED always ON Sensor setpoint alarm Change alarm setpoint to end alarm condition Sensor warning Look for sensor warning details in sensor alarm log Circuit board failure Replace circuit board 3 2 7 Alarm Log Sensor Warnings The following table presents sensor warnings displayed in the Alarm Log their possible causes and corrective actions See the AquaTrend Interface Manual for information on accessing the Alarm Log 28 SECTION 3 continued 3 2 8 Voltage Measurements Measure the following voltages directly on the 1720D circuit board using a Digital Volt Meter DVM For all measurements connect the black ground lead of the DVM to TPI Table 12 Sensor Alarm Log Troubleshooting Table Sensor Warning Possible Cause Corrective Action Lamp burned out Replace lamp Lamp unplugged Restore connection Bad Lamp Red wire 12 V disconnected Restore connection Dislodged lamp Reinstall lamp Bad circuit board Replace circuit board Photocell coated dirty Clean the photocell window Photocell wires disconnected Reconnect wires Replace photocell Photocell broken cracked Contact the Hach Service Department Low Signal Lens coated dirty Clean the lens usi
53. lication program code as well as non volatile data calibration measurement options location etc Similarly a HM6264A RAM chip 8K x 8 stores volatile data while the Neuron Chip is running Two 74Fxx series logic chips provide the necessary decoding for the memory map as shown in the following table Table 2 Memory Map Address Hex Description 0000 BFFF Flash Memory C000 DFFF RAM E000 FFFF Internal Neuron Chip Memory The Neuron Chip is connected to a 5 MHz crystal which provides the time base for all memory access and timing functions Low voltage detection and power on delay are provided by a DS1233 EconoReset chip The FTT 10A transceiver is used as the interface between the Neuron Chip and the twisted pair wire The FTT 10 supports polarity insensitive free topology wiring making network installations extremely simple A built in transformer magnetically isolates the 1720D from the network ensuring that problems such as ground loops or noise spikes do not affect the system Network wire lengths up to 500 meters are supported with a maximum device to device length of 400 meters Longer network wire lengths are supported with an AquaTrend Repeater Cat No 52200 00 11 SECTION 1 continued 1 6 1 5 Volt Generator 1 6 2 Lamp Driver 1 6 3 Configure Button System 5 volts is converted to approximately 5 volts by an ICL7660 and associated components This voltage is used by the ICL7650 op am
54. links once every three seconds corresponding to when a measurement is taken in normal operation The status LED lights steady when the 1720D is in an alarm condition high or low setpoint alarm or sensor warning Alarms associated with a specific sensor are shown in the alarm log for that sensor as indicated by a number at the bottom of the AquaTrend display The 1720D software was developed in Neuron C a derivative of ANSI C written specifically for the Neuron Chip This allows standard C code and data structures to be used with very few modifications At power up the 1720D performs the following steps Initializes all variables both internal variables and SNVTs Initializes all hardware LEDs A D converter etc e Reads system volts and high low gain detector values with the lamp off dark values e Broadcasts a power up message to the master AquaTrend e Turns the lamp on e Reads system volts to determine if the lamp is functional Reports any startup errors in the alarm log 13 SECTION 1 continued 1 7 2 Idle Loop After power up the 1720D enters the idle loop This loop executes indefinitely until power is removed from the 1720D The following steps occur in the idle loop Reads detector value e If necessary switches gain and re reads detector value Computes turbidity e Sends turbidity values to the following devices if installed on the network Master AquaTrend 1 e Remote AquaT
55. log contains impor tant data In addition alarms may be triggered SENSOR MENU jMILLIvOLT DISPLAY jE orf irira The fourth line of the test mode menu displays the current lamp setting To change the lamp setting select LAMP SETTING then press ENTER Test mode is automatically set to ON when either option is selected Under normal operation the lamp is switched on approximately 20 seconds after power is applied to the instrument dark values are read during this time The lamp is always left on after the initial power up period unless ZERO ELECTRONICS is selected which repeats the 20 second dark value reading period See Section 1 5 on page 8 for more information on the lamp circuit The last line of the test mode menu displays the current status of the millivolt display selection To change the millivolt display setting select MILLIVOLT DISPLAY then press ENTER Test mode is automatically set to ON when either option is selected When the millivolt display is set ON the units are changed from NTU to mV and the millivolts at the A D converter are displayed on the AquaTrend and Digital Display Module When the millivolt display is set to OFF the units are returned to NTU and turbidity is displayed When the multiplexer is set to the detector channel the millivolt range displayed is 2500 to 2500 mV This voltage can be directly measured with a volt meter at the input to the A D converter See the Voltage Measurem
56. lues are subtracted from each reading to compensate for ambient light reaching the detector If the a d converter reads overrange full scale out of the amplifier for high gain dark LIGHT LEAK is recorded in the alarm log and the AquaTrend sensor alarm indicator is set denoted by a small box with a number in it at the bottom of the AquaTrend display The 1720D attempts to continue reading turbidity even after LIGHT LEAK is stored in the alarm log Typically LIGHT LEAK indicates the head was not seated on the body while the 1720D was powered up Selecting ZERO ELECTRONICS from the CALIBRATION menu re reads the dark counts Alternatively power can be cycled to the 1720D which also re reads the dark counts Other possible causes of LIGHT LEAK are a light leak in the 1720D body reversed detector leads or bad amplifier circuit In software version 2 0 LIGHT LEAK was called HI DARK COUNTS After the dark counts are read see LIGHT LEAK above the 1720D reads the 5 system voltage with the lamp off and the lamp on If the two readings do not differ by more than 3000 a d counts 14 3 millivolts BAD LAMP is stored in the alarm log and the AquaTrend sensor alarm indicator is set denoted by a small box with a number in it at the bottom of the AquaTrend display After power up the lamp on 5 system voltage is read once per hour to ensure the lamp is not burned out The 1720D attempts to continue reading turbidity even after BAD LAMP is store
57. ment is displayed without affecting any of the settings This is useful for example for determining if the gain is switching properly high gain should be selected at approximately 10 NTU and below The status of Test Mode is shown in this menu To change test mode select TEST MODE then press ENTER The automatic updates of Mux channel gain setting and lamp state are disabled when test mode is set to ON When mux channel gain or lamp state are manually set see sections below test mode is automatically set to ON Test mode is automatically set to OFF when power is cycled to the instrument MAIN MENJ P ALARM LOG AGUATREND MENU E sEMSOR MENU OTHER DEVICE MENMU NETWORK MENU B1 B1 37 SENSOR MENU E P 17280 TURG 1_1720D PRINT TURE SETUP CLEAR ALARM LOG SENSOR COLD START SEMSOR RESET DISPLAY STARTUP VALUES TEST MODE MENU SENSOR MENU ALARM SETUP RECORDER SETUP MEASUREMENT OPTIONS SILENCE ALARMS HOLD OUTPUTS SENSOR DIAGNOSTICS More 6ir ira7 snp a D SENSOR MENU Ed SELECT SENSOR E 172080 TURB 41_1728D AE SENSOR MENU r 17200 TURE 41 1728D SENSOR DIAGNOSTICS TEST MODE MENU E TEST MODE Off MUS CHRMMEL DETECTOR AMPLIFIER X32 LAMP SETTING on MILLIVOLT DISPLAY OFF 4 5 1 Mux Channel Note Changing to system volts may cause an alarm s to trigger 4 5 2 Amplifier Setting The second line of the test mode menu displays the current multiplexer mux setting
58. nfigure Button comi egredere d Etpe Re Cerise ire epe n erede 12 1 6 4 Portable AquaTrend Interface nennen ete ient eee eee nre Re EL Pei e Ene eda 12 1 6 5 E ED Indic tors 5n UE tem ete iB ttn tme teni te te eet cena p pe iere Ene aded 12 1 6 5 D PowerLED dne EO e TR PER bald owes iU E EEE OE AEE ee b iia 12 1 6 5 2 Configure LED lt a ber oe eR a S a aa t RR Ee edet i ees 13 1 6 5 3 Status EED estet tds E he tete ate rte tiet ce tende A ore ee tutes be eis e meus 13 ISO Wal 2I nettes Chiedi tee ret teet e dnte Eo EP ORE te Hen es Rep ele ges pee eth ys 13 ITI Power Up ue ege denda ade ne eed e eed 13 127 2 dle boop m 14 1 73 Menu Mode iet bipolar eed Ri e RH aussie ti 14 1 7 AA A ue uet eee E a e RP e RON 14 1 74 Zero Electronics inire Rt tta ere efie dte de eme 15 1 22 Normal CAMDEN 2 ni Re trt e eti Cede e RE RE EH e a 15 1 7 4 3 Comparative Calibration nre are Se noie eet in eee teet eie tti ae eet p Pee e D d dua 16 174 4 Calibration History iter eite ete p ru d Per t Pe e e Sova 16 1 7 5 bon Works Technology tette cte cede ecto ete teer eere de a dada een aR 17 1 9 Required Tools and Equipment ee RR epe eere RU HR aes taie 18 SECTION 2 INSTRUMENT INSPECTION AND CHECKOUT eee 19 2 1 Test Methodi aus sonne RR DR pn ee UR ture a bm S 19 2 2 Checkout Sheet Procedure icta gt eu ede ten ente ine ee te cem eset epus e eti Eee 19 22 1 Visual Inspection iniu ete e ied oett
59. ng isopropyl alcohol and a cotton swab Obstructed light path Remove obstruction Sample turbidity gt 100 NTU See Bad Lamp causes above Switch to a high range turbidimeter such as the Hach SS6 See Bad Lamp corrective actions above Bad System Voltage A D Converter Timeout Improper wiring at power supply See the PS1201 Power Supply Manual Cat No 52010 18 Turbidimeter head cable shortened to improper length Contact Hach Service Department Fluctuation in power supply voltage Turn power to the instrument off and back on Bad circuit board in turbidimeter head Contact the Hach Service Department Light Leak High Dark Counts in Software Version 2 0 Light Leak Turbidimeter head not properly aligned on the turbidimeter body or calibration cylinder during Power Up or Zero Electronics Make sure the turbidimeter head is properly aligned and repower instrument or perform ZERO ELECTRONICS in the Calibration Menu Photocell broken cracked Contact the Hach Service Department Table 13 Voltage Measurements Name Reference Designator Typical Voltage 5 0 V de with lamp on tdg An 5 25 V dc with lamp off 12 V dc J1 9 12 0 V dc A D Reference TP2 2 5 V dc Lamp Driver J3 1 4 2 V dc Photcell A D Input U3 8 5 to 45 V dc Voltage Divider A D Input U3 9 2 oun lamp en 2 1 V dc with lamp off 29 SECTION 3 continued
60. nued 4 3 Service Menu Access MAIN MEHI P ALARM LOG AGUATRE MD MEHU SENSOR MENU OTHER DEYICE MENU NHE TWORK MENU 61 6109 Service menu access allows service personnel to access menu options not normally available to users To enable service menus a password must be entered as shown in the following screens 1 Press the MENU key 2 Select AQUATREND MENU 3 Select AQUATREND DIAGNOSTICS 4 Select SERVICE MENU 5 Use the arrow keys to enter the password AMES then press the ENTER key AGUATRENG MENU AGUATREND MEHU AGUATREND MEHU d Ll F DISPLAY SETUP DISPLAY TEST LANGUAGE English KEYBOARD TEST ENTER PASSWORD EDIT MAME MEMORY TEST SET TIME DATE VERIFY PROGRAM CHECKSUM AMER SECURITY SETUP CLEAR ALARM LOG Use Arrow Keys PRINT DATA LOG AGUATREND COLD START Press ENTER To Accept AGUATREND DIAGNOSTICS SERVICE MENU E PELSEEE When the service menu is enabled an S is displayed in the lower right corner of the AquaTrend display indicating service mode is active The time field alternates between time 00 00 and the minutes remaining in service mode 359 as shown below Service access is turned off by again accessing SERVICE MENU from the AQUATREND DIAGNOSTICS menu Alternatively service access is automatically turned off after 360 minutes 6 hours Once service access has been granted via the AquaTrend the following changes occur to the 1720D e Visible display of the DISPLAY STARTUP VALUES
61. ons menu See Table 12 1720D Sensor Settings f Calibrate the 1720D according to the instructions in the Calibration section of the 720D Instrument Manual 5 3 Circuit Board Replacement Replace the 1720D circuit board Cat No 52031 00 by performing the following steps 5 3 1 Circuit Board Removal Note Wear a grounding strap when 1 Remove power from the 1720D Ensure the green power LED is touching any of the circuit board not illuminated components 2 Remove the 1720D head from the body Turn the 1720D head assembly over so the photocell faces up see Figure 5 3 Remove the five Phillips screws Cat No 5587 11 from the perimeter of the turbidimeter head assembly 4 Separate the turbidimeter head assembly into two parts The head assembly top Cat No 52018 00 contains the circuit board The head assembly bottom Cat No 52017 00 contains the photocell and lamp Figure 5 Disassembling the Turbidimeter Head Assembly Screws Cat No 6956 12 Washers Cat No 5587 11 5 Places 44 SECTION 5 continued Refer to Figure 6 and disconnect the wires from connectors J1 J2 and J3 as follows Loosen the 3 screws holding each wire in J2 and remove each wire Loosen the 2 screws holding each wire in J3 and remove each wire Loosen the 12 screws holding each wire in J1 and remove each wire Remove the two Phillips screws Cat No 7511 11 from the circuit board Cat No 52031 00 s See Figur
62. or J3 according to Table 19 Table 19 Terminal Block J3 Wire Colors Position Wire Color Wire Source 1 Black Lamp 2 Red Lamp 52 SECTION 5 continued When wiring is complete reassemble the turbidimeter head assembly as follows 1 Place five washers Cat No 6956 12 on five Phillips head screws Cat No 5587 11 Make sure the gasket Cat No 52028 00 between the two components is in place and route all wires so they do not touch the lamp heatsink Position the head assembly top on the head assembly bottom Before tightening the screws make sure no wires are pinched between the two halves Place the five screws and washers assembled in step into the holes in the cap bottom and tighten Place the 1720D head on the body Restore power to the PS1201 that is supplying power to the 1720D and ensure the power LED is on Recalibrate the 1720D turbidimeter per the user manual 53 54 SECTION 6 REPLACEMENT PARTS 1720D Standard Accessories Description Unit 1720D Sensor Head Assembly 5 4 ec er aeter eteo taber tet eter ed eee dd each Formazin Primary Standard decns esenee n ee etes ett ree hee eene terae petet un 500 mL Filter 0 45 um to produce ultra filtered water for cleaning and calibration each Filter 0 2 um to produce ultra filtered water for calibration standard preparation each Lamp Assembly MEER each PST201 P wer
63. ot Communication Cable 22 gauge 2 conductor shielded sss 100 ft Communication Cable 22 gauge 2 conductor shielded sss 250 ft Communication Cable 22 gauge 2 conductor shielded oonconninncnnncicnnnconnnccnnonaconncncnancnonnss 500 ft Communication Cable 22 gauge 2 conductor shielded sss 1000 ft Communication and Power Cable 20 gauge 4 conductor shielded per foot Communication and Power Cable 20 gauge 4 conductor shielded 100 ft Communication and Power Cable 20 gauge 4 conductor shielded 250 ft Communication and Power Cable 20 gauge 4 conductor shielded 500 ft Communication and Power Cable 20 gauge 4 conductor shielded 1000 ft Digital Display Module DDM esses enne non non nono eren ennt enne each Drain plug for the 1720D body cde tede tert det ete eee te eee E eese ge each ICE PIC Module for Calibration and Calibration Verification 20 NEU s et E NIA a RR inte HAN each Ip UD mE each QNT ien A En PETS each Deionized Waters 5555235 seg HOW eene m PEER as 1L 55 m 26705 00 seed deines 23238 10 EE 18950 00 po 52010 00 VERREES 52012 00 DOT 44117 00 Rubeus 51414 00 VEREER 52006 00 riada 52007 00 os 52012 00 M 52069
64. p as well as the CS5504 A D converter The lamp driver circuitry consists of an IRF541 power MOSFET transistor an LM358 dual op amp and several discrete components The IRF541 regulates the lamp voltage to approximately 4 2 volts at 2 amps A slow turn on is inherent in the design and protects the lamp from high inrush currents that would cause premature lamp failure The lamp is operated in constant voltage mode The configure button also know as the service pin in LonWorks terminology is used during installation of the 1720D When this button is pressed the SERVICE input to the Neuron chip is grounded causing the Neuron chip to send a unique 6 byte ID out on the network This ID is used by the AquaTrend for identification and configuration purposes The configure LED is illuminated to full intensity while the configure button is pressed A second use for the configure button is to return the 1720D to the unconfigured state configure LED flashing See Section 3 3 2 on page 31 for more information on this topic 1 6 4 Portable AquaTrend Interface 1 6 5 LED Indicators 1 6 5 1 Power LED The Portable AquaTrend is connected via a 5 pin sealed connector on the front face of the 1720D This connector contains two network connections 12V circuit ground and remote service Remote service is grounded by the Portable Aqua Trend to indicate it is ready for the 6 byte ID message from the 1720D A 4N38 opto isolator is used
65. per order Same Standard Calibration standards Deionized Water 20 NTU read the same turbidity value Repeat the calibration procedure with the proper standards Deionized Water 0 5 The calculated NTU value of the deionized water is greater than 0 5 NTU Use filtered water if necessary and re mix standards Clean the calibration cylinder and repeat the calibration procedure 3 2 4 Power Indicator During normal operation the green power LED on the 1720D head is illuminated indicating power is being supplied to the 1720D If the power LED is off there is no power being supplied to the 1720D or the wiring is not properly connected Refer to the PS 201 Power Supply manual Cat No 52010 18 for detailed wiring information Table 9 Power LED Troubleshooting Table Symptom Possible Cause Corrective Action Power LED always OFF Power supply problem Check red black and orange connections at power supply and on circuit board Measure 12V and 5V system voltages Power not being supplied Check 110 220 volt connections in power supply Bad circuit board Replace circuit board 27 SECTION 3 continued 3 2 5 Configure LED The yellow configure LED provides information about the state of the device The following table describes the state of the device after power up The configure LED is illuminated when the configure button is pressed Table 10
66. r a normal or comparative calibration da P P SENSOR MENU L SELECT SENSOR E 17280 TURE 41_1728D SENSOR MENU E SENSOR MENU ALARM SETUP 32 AMP DARK B 2 RECORDER SETUP PRINT TURE SETUP j41 AMP DARK B 1 MEASUREMENT OPTIONS CLEAR ALARM LOG LAMP OFF 45v 5242 4 SILENCE ALARMS SENSOR COLD START LAMP OM 3v 4831 3 HOLD OUTPUTS SEMSOR RESET B Return B SENSOR DIAGNOSTICS DISPLAY STARTUP VALUES Ca More 3 TEST MODE MENU BELREEF PBELREEF 5 irira 3 SENSOR MENU irira The difference between the lamp on voltage and lamp off voltage represents the voltage drop in the 1720D cable due to the lamp The 1720D automatically reads the lamp once per hour and if there is no voltage drop reports a BAD LAMP sensor warning in the 1720D error log Very low lamp on 5V values may mean a poor connection especially at the PS1201 Power Supply 4 5 Test Mode Menu The test mode menu allows service personnel to view the 1720D s multiplexer gain and lamp settings and allows each to be controlled manually This is useful for diagnosing problems with the 1720D since these settings are normally automatically controlled by the 1720D s microprocessor Access this menu from the AquaTrend SERVICE MENU as follows 1 Press the MENU key followed by SENSOR MENU 2 Choose the appropriate sensor 3 Select SENSOR DIAGNOSTICS 4 Select TEST MODE MENU 38 SECTION 4 continued From this menu the current state of the instru
67. r du porsonnel qualifi WARNUNG Arbeiten Sie nicht mit besch digter order defekter Testausr stung Benutzen Sie ausschieflich geerdete Steckdosen und Stromkabel es sei denn im Verfahren sind andere Angaben gemacht Diese sollten nur von augebildeten Personen durchgef rhrt werden 1 Remove the instrument from the packing carton 2 Ensure there are no cracks or other defects that can be detected visually in the instrument housing Also ensure the lamp and photocell are free of cracks pits or other abrasions If defects are found replace the items as described in Section 5 Repair and Upgrades 3 Record Pass or Fail for Step 1 of the checkout sheet depending on the condition of the instrument 19 SECTION 2 continued 2 2 2 Add Device Test 1 Place the 1720D head on an empty calibration cylinder Connect the 1720D head to a PS1201 Power Supply and an AquaTrend 2 Supply AC input power to the PS1201 Verify that the green Power LED illuminates on the 1720D head and that the AquaTrend display is functional 3 Ensure the configure LED is flashing once per second If it is not see Section 3 3 2 Manually Unconfiguring the 1720D on page 31 4 Press MENU on the AquaTrend Select NETWORK MENU followed by SINGLE SENSOR SYSTEM 5 Press ENTER to continue when the list of devices is shown 6 Ifthe OPERATION COMPLETE screen appears the Add Device Test was successful 7 Record Pass or Fail for Step 2 of the checkout
68. rends up to 8 Portable AquaTrend e Digital Display Module 1 e Signal Output Modules up to 4 two alarms and two recorders e Serial I O Modules up to 2 Once per hour reads the system voltage lamp test and autocalibrates the A D converter e Ifa menu is requested sends a string back to the appropriate AquaTrend 1 7 3 Menu Mode When the user selects the 1720D from an AquaTrend SENSOR MENU the 1720D begins transmitting menu strings in response to each ENTER key press on the AquaTrend These menus contain information on calibration alarms relays measurement options sensor location etc The 1720D continues to run its idle loop during menu display so that readings continue as normal 1 7 4 Calibration Five calibration procedures are presented in the instrument manual supplied with the instrument Table 3 summarizes each method A denotes the least time and or the lowest cost in each category Table 3 Calibration Procedures Compared Calibration Time EPA Standards Reagent Accessory Accessories Required Type Reporting Required Cost Cost q User prepared C Yes 2 B B Cal Cylinder TenSette Pipet 4000 NTU Formazin e aed a Yes 1 S B Cal Cylinder StablCal standard Standards Comparative C Yes 1 A A None 4 TM IKE IO A No 1 P ICE PIC Fixture Module Multi turb B Yes 1 C B Cal Oylinder StablCal standard 14 SECTION 1 continued 1 7 4 1 Zero Electronics MAIN
69. s 10 SECTION 1 continued 1 5 2 5 A D Converter The Crystal CS5504 A D converter is used to convert analog voltages to their digital representations This is a 20 bit delta sigma A D with two differential inputs One input is used to measure the amplified photocell voltage and the other is used to measure the system voltage A 2 5 volt reference is used allowing the input voltage to range from 2 5 to 2 5 volts An external 32 768 kHz crystal clock is connected to the CS5504 providing noise rejection at 50 and 60 Hz power line frequencies In addition the CS5504 contains self calibration circuitry that is initiated once an hour to ensure minimum offset and full scale errors Communication between the CS5504 and the Neuron chip is achieved via a three wire SPI type serial interface An A D conversion is performed once every three seconds The status LED is illuminated while the A D conversion cycle is in progress providing the 3 second blink See Section 1 6 5 3 on page 13 for more information on the status LED 1 5 2 4 Microprocessor and Memory 1 6 Network Interface The Motorola MC143150 is the microprocessor also called the Neuron Chip used to control the 1720D This device contains three separate processors to control the network communications as well as the application program Internally the MC143150 contains 2K of RAM and 512 bytes of EEPROM Externally an AT29C512 flash memory chip 64K x 8 stores the app
70. ssful 3 Remove the Portable AquaTrend from the remote connector 4 Record Pass or Fail for Step 4 of the checkout sheet 2 2 5 Sensor Startup Values Note The AquaTrend SERVICE 1 Enable the Service Menu using the instructions in Section 4 3 on page 37 MENU must be enabled to perform steps 5 8 2 Press MENU on the AquaTrend Select SENSOR MENU 3 Press ENTER to select the 1720D 4 Select SENSOR DIAGNOSTICS 5 Select DISPLAY STARTUP VALUES MAIN MEHU SENSOR MENU SENSOR MENU gt SELECT SENSOR ALARM LOG E 17280 TORE 41 1728D ALARM SETUP AGUATREND MENU RECORDER SETUP SENSOR MENU MEASUREMENT OPTIONS OTHER DEVICE MENU SILENCE ALARMS NETWORK MENU HOLE OUTPUTS El SENSOR DIAGNOSTICS Ca MORE 7 61 61 97 61 61497 SENSOR MENU P 17205 TURG 1_1720D PRINT TURE SETUP CLEAR ALARM LOG SENSOR COLD START LAMP OM 5v 4831 3 SENSOR RESET B Return DISPLAY STARTUP VALUES TEST MODE MENU 61 61 97 5 BEL REEF 21 SECTION 2 continued X32 Amplifier Gain Dark Millivolts Test 1 Note the value displayed next to X32 AMP DARK If the number is 0 1 to 0 1 the X32 Amplifier Gain Dark Millivolts Test was successful 2 Record Pass or Fail for Step 5 of the checkout sheet X1 Amplifier Gain Dark Millivolts Test 1 Note the value displayed next to X1 AMP DARK If the number is 0 1 to 0 1 the X1 Amplifier Gain Dark Millivolts Test was successful 2 Record Pass or Fail for Step 6 of the ch
71. t No 52000 60 Model 1720D Low Range Process Turbidimeter Follow the 1720D check out sheet found on the last page of this manual when repairing each instrument Completed check out sheets provide the customer with useful information when returned with the repaired instrument 2 2 Checkout Sheet Procedure WARNING Do not use damaged or defective test equipment Use only a power receptacle and power cord with earth ground for all test equipment unless the procedure specifies differently Only trained personnel should perform these tests 2 2 4 Visual Inspection ADVERT NCIA N o use equipamento de teste defeituoso ou que ofere a perigo Use somente tomada e cabo de energia com ligac o terra para todos os equipamentos de teste a menos que a instruc o do procedimento seja diferente Somente pessoal treinado est autorizado a executar os testes ADVERTENCIA No emplee equipo de probar daf ado o defectuoso Conecte solamente a un recept culo y use un cable con polo a tierra para todos los aparatos de prueba a menos que el procedimiento especifique algo diferente Estas pruebas deben ser ejecutadas solamente por personal debidamente adiestrado ATTENTION Ne pas utiliser d quipement d essai endommag ou d fectueux Utiliser seulement une prise de courant et un c ble d alimentation avec torre pour tout le mat riel d essai sauf instruction contraire dans la proc dure d essai Ces essais ne doivent tre effectu s que pa
72. ter head bottom and top and the circuit board Replacement parts and part numbers can be found in REPLACEMENT PARTS on page 55 of this manual The 1720D was designed for hand assembly and disassembly Wear cotton gloves or finger cots to avoid contaminating the printed circuit boards and optical components Always assemble and disassemble the instrument in a static free environment while wearing a grounded static discharge wrist strap A brief overview of each functional section of the 1720D Low Range Process Turbidimeter follows The 1720D Low Range Process Turbidimeter operates on the principle that the amount of light scattered from a sample is proportional to the quantity of particulate material in that sample Light from a tungsten lamp is collected by a glass lens and directed through a smooth upflowing water surface in the turbidimeter body This design eliminates a glass window between the light source and the sample which would require regular cleaning cause stray light scattering and limit sensitivity at low turbidity levels Problems with condensation and filming on the exterior of a window also are eliminated by this design Light scattered by particles in the sample is detected by the submerged photocell at an angle of 90 to the light beam A filter in front of the photocell causes the detector response to peak at a wavelength between 400 nm and 600 nm in compliance with USEPA guidelines USEPA Method 180 1 Turbidity is c
73. ts NOT ASCENDING DI water standard read higher NTU value than second standard SAME STANDARD DI water standard read the same as the second standard DI WATER gt 0 5 DI water computed to be greater than 0 5 NTU DIV ZERO Divide by zero encountered 16 SECTION 1 continued The same information displayed in CAL HISTORY can be sent to a computer or printer via a Serial Input Output Module SIO by selecting PRINT CAL HISTORY 1 7 55 LonWorks Technology The 1720D utilizes LonWorks technology a complete platform for implementing control network systems These networks consist of intelligent devices that interact with their environment and communicate with one another using a common message based control protocol This protocol commonly referred to as the LonTalk protocol is an open standard developed by Echelon to promote interoperable or inter vendor compatible network products The Hach AquaTrend system uses the LonTalk protocol to communicate between AquaTrend network devices Unlike a pure LonWorks based system however the AquaTrend utilizes a string based messaging scheme This allows menu strings to be stored locally in each device eliminating the need to upgrade the AquaTrend whenever a new device is developed Multiple language translations are also possible with this scheme In addition to the AquaTrend messaging scheme the 1720D includes LonMark network variables to allow interoperability with other

1720D Low Range Process Turbidimeter SERVICE MANUAL

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