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LI-610 Manual - LI-COR

1. 5 62 100 90 1 80 4 70 a A 69 2 3 2 50 um i 40 gt 2 30 A IA 20 1 s LA A 7 0 0 0 5 10 15 20 25 30 35 Temperature C Psychrometric Chart showing temperature vapor pressure and relative humidity 0 to 35 C C 2 Psychrometric Charts Appendix D LI 610 Calibration Traceability Condenser Block Thermistor The following discussion is intended for those users interested in the traceability of the procedures used when calibrating the LI 610 The copper condenser block temperature is used to calibrate the LI 610 The temperature of the condenser block can be measured with greater accuracy and resolution than the dew point of the output air stream as measured by a dew point hygrometer The water temperature inside the condenser block is established by the block temperature and air brought to saturation at the water temperature will have a dew point equal to the water temperature Testing has confirmed that air leaving the LI 610 is saturated at flow rates up to 2 liters min with a dew point equal to the block and water temperature The platinum Resistance Temperature Detector RTD mounted on the copper condenser block is calibrated at two temperatures 0 C and 49 90 C Any slight non linearity of the R
2. Figure 4 3 Calibration dialog box in PC communications software The calibration dialog box allows you to define a calibration action to be performed for CO and or H5O You then flow the appropriate gas es through the appropriate cell s wait for the readings to stabilize and then press DoCO2 f2 or DoH2O f3 to execute the calibration action For the next 4 or 5 seconds the LI 7000 will average the readings it is taking then perform the requested action There are three major choices for calibration actions 1 Make cell A read 2 Make cell B match cell A 3 Make cell B read The Make cell A read option is designed to correct the drift with time that occurs while in Reference Estimation Mode REM This action is not available from the front panel unless you are in REM You perform this procedure while temporarily flowing a known concentration through cell A Any concentration will work even 0 Calibration 4 5 Section 4 Calibration Instructions The Make cell B match cell A option is the most common procedure You flow the same air through both cells and execute this procedure to remove the effects of dirt and other sources of error You don t need to know the actual concentration of this gas but it should be stable There is a subtlety here if you match the cells at one concentration you may find that the cells are no longer matched at a different concentration The LI 7000 can adjus
3. 2 The chamber vapor pressure must be 40 x 100 poe cx 2 82 kPa e 1 128 kPa 3 The LI 610 setpoint temperature necessary to give a vapor pressure of 1 128 kPa is equivalent to the dew point temperature corresponding to a vapor pressure of 1 128 kPa Solving equation 3 4 for T 240 97z where z In 17 502 z 0 61365 In 128 0 6088 0 61365 T 8 7 C the LI 610 setpoint The psychrometric chart in Figure 3 2 can also be used to find an approximate solution This is especially valuable when trying to quickly find the LI 610 dew point temperature necessary to give a desired incoming humidity while making photosynthesis measurements in the field With reference to Figure 3 2 find the chamber or device temperature on the x axis read up to the desired humidity line and note the vapor pressure on the y axis Then at constant vapor pressure read across the chart to the left until the 100 RH curve is reached Finally Operation 3 11 Section 3 read down to the corresponding temperature on the x axis This will be the LI 610 setpoint temperature Example 2 Now suppose we have a problem similar to Example 1 but working at a flow rate of liter per minute leads to a condenser over pressure of 2 kPa at a total barometric pressure of 97 kPa in the leaf chamber Assume the chamber temperature is 23 0 C and the desired relative humidity is 40 as before The first two steps to so
4. Air Output Ports Command Input Figure 2 3 11 610 front panel 2 6 Pre Operation Section lll Operation General Description Air Flow Through the LI 610 The LI 610 Portable Dew Point Generator is a completely self contained instrument that is used to generate a moist air stream with a known dew point A source of dry or ambient air is bubbled through a condenser block assembly containing a water bath whose temperature is precisely controlled by a series of Peltier thermoelectric coolers The internal radiator and fan assembly dissipates the heat generated by the coolers providing a self contained cooling system Water and air flow through two distinct paths within the LI 610 to produce a moist air stream with a known dew point Air is drawn into the LI 610 through the AIR IN fitting on the instrument back panel Any impurities are removed from this air stream by a filter before it reaches the air pump Air leaving the pump passes through a flow adjust valve on the instrument front panel where the rate of air flow through the LI 610 is controlled see Figure 3 1 The air stream then enters the two copper condenser blocks via the TO CONDENSER fitting where a bubbler stone is used to maximize the air to water surface area which ensures that air leaving the condenser blocks is completely saturated with water vapor Water vapor leaving the condenser blocks through the FROM CONDENSER fitting is split into two separ
5. Temp Set position regardless of what the knob setting is Connect the red lead from the BNC connector to the positive terminal of the output device and the black lead to the signal ground The output device must be able to supply 1 mA drive current A source impedance lt 100 is required for an error lt 0 1 D NOTE The LI COR LI 6400 Portable Photosynthesis System can be configured to provide an analog output channel that controls the dew point temperature of the LI 610 If both instruments are powered by AC power a ground loop can develop in which there is more than one ground connection path between the two pieces of equipment Ground loop induced voltages cause unwanted signal noise that can affect the operation of the LI 610 If you are using the LI 6400 and LI 610 in this manner we recommend that you isolate the two circuits by operating one or both of the instruments with battery power Analog Output The Analog Output connector is similar to the Command Input connector in that BNC millivolt leads are used to provide an analog signal from the LI 610 to an external recording device Analog output is also linear 5 volts and is equivalent to 1 C per 100 mV Connect the red lead to the positive terminal of the readout device and the black lead to the signal ground The readout device should have an input impedance 2100kQ for an error lt 0 1 the Analog Output impedance is 100Q 3 4 Operation Section 3 D
6. 11 6262 etc Then by definition w610 610 P AP and Wmeas meas P but W610 Wmeas SO SEG 3 6 meas P AP 610 3 8 Operation Section 3 Equation 3 6 shows that the same 5 kPa over pressure now causes nearly a 5 reduction in vapor pressure when measured in the LI 6262 or other instrument at atmospheric pressure Errors due to condenser over pressure can be minimized in two ways First condenser pressure can be measured and an appropriate correction can be applied using equation 3 6 This should be done when the LI 610 is used as part of a photosynthesis system because high flow rates are sometimes required and the gas exchange system may have extensive plumbing both leading to significant condenser over pressures The 610 03 Digital Pressure Meter is available as a useful accessory to make this measurement It has an analog output signal that can be automatically recorded and used in the calculations of the LI 6200 Portable Photosynthesis System for example Alternatively one can use a water or mercury manometer to measure the condenser over pressure and make the corrections manually A second method for minimizing condenser over pressure is to use low flow rates and a short flow path between the LI 610 and the water measuring instrument This would be the normal configuration when using the LI 610 to calibrate another instrument The device to be calibrated should be attached to the LI 610 with a short
7. 4 Turn the AIR PUMP switch ON The air pump will turn on starting the flow of moist air out of OUTPUT 1 and OUTPUT 2 Use the FLOW ADJUST knob to control the rate of air flow through the LI 610 If you wish to shut off OUTPUT 2 simply turn the knob on the rotameter above OUTPUT 2 clockwise until the flow is shut off and the rotameter shows zero flow Allow the LI 610 time to reach the desired dew point The time required will depend on the difference between the desired dew point temperature and the temperature of the cooling water used to remove heat dissipated by the Peltier coolers As an example at 20 C ambient air temperature the LI 610 will take approximately 10 minutes to reach a dew point of 0 C assuming that the cooling water temperature is also at or just above 20 Operation 3 3 Section 3 Command Input The Command Input connector is used to provide a means of controlling the temperature setting of the LI 610 from an external device i e a computer with an analog output board One BNC connector with attached millivolt leads is included for connection to this device The Command Input requires a 0 to 5 volt input the corresponding temperature set is linear and is equivalent to 1 C per 100 mV For example an input signal of 3250 mV would produce a dew point temperature output of 32 50 C The display will show the actual temperature set point for the Command Input when the selector switch is in the
8. 5 5 amps maximum current draw or 108 126 216 252 VAC with 610 01 AC module 8 kg 17 7 Ibs with 6200B Rechargeable Battery 7 86 kg 17 4 Ibs with 610 01 AC Module 23 5 x 21 x 28 5 cm H x W x D 9 8 1 x 11 Specifications 1 Appendix B Saturation Vapor Pressure Table Temp C 0 2 E 4 E 6 3 8 9 0 0 614 0 618 0 623 0 627 0 632 0 636 0 641 0 646 0 650 0 655 1 0 660 0 664 0 669 0 674 0 679 0 684 0 689 0 694 0 699 0 704 2 0 709 0 714 0 719 0 724 0 729 0 734 0 740 0 745 0 750 0 756 3 0 761 0 766 0 772 0 777 0 783 0 788 0 794 0 800 0 805 0 811 4 0 817 0 822 0 828 0 834 0 840 0 846 0 852 0 858 0 864 0 870 5 0 876 0 882 0 888 0 894 0 901 0 907 0 913 0 920 0 926 0 932 6 0 939 0 945 0 952 0 958 0 965 0 972 0 979 0 985 0 992 0 999 7 1 006 1 013 020 027 1 034 1 041 1 048 1 055 1 062 1 070 8 1 077 1 084 092 099 1 107 1 114 1 122 1 129 1 137 1 145 9 1 152 1 160 168 176 1 184 1 192 1 200 1 208 1 216 1 224 10 1 233 1 241 249 258 1 266 1 275 1 283 1 292 1 300 1 309 11 1 318 1 326 335 344 1 353 1 362 1 371 1 380 1 389 1 399 12 1 408 1 417 427 436 1 445 1 455 1 465 1 474 1 484 1 494 13 1 503 1 513 523 533 1 543 1 553 1 563 1 574 1 584 1 594 14 1 605 1 615 626 636 1 647 1 657 1 668 1 679 1 690 1 701 15 1 712 1 723 734 745 1 756 1 768 1 779 1 790 1 802 1 814 16 1 825 1 837 849 860 1 872 1 884 1 896 1 908 1 921 1 933 17 1 945 1 957 970 982 1 995 2 008 2 020 2 033 2 04
9. 7 983 8 025 8 068 8 110 8 153 8 196 42 8 239 8 283 8 327 8 370 8 414 8 459 8 503 8 548 8 592 8 637 43 8 683 8 728 8 774 8 819 8 865 8 912 8 958 9 005 9 052 9 099 44 9 146 9 193 9 241 9 289 9 337 9 386 9 434 9 483 9 532 9 581 45 9 631 9 680 9 730 9 780 9 830 9 881 9 932 9 983 10 034 10 085 46 10 137 10 189 10 241 10 293 10 346 10 399 10 452 10 505 10 559 10 612 47 10 666 10 720 10 775 10 830 10 885 10 940 10 995 11 051 11 107 11 163 48 11 219 11 276 11 333 11 390 11 447 11 505 11 562 11 621 11 679 11 737 49 11 796 11 855 11 915 11 974 12 034 12 094 12 155 12 215 12 276 12 337 50 12 399 12 461 12 523 12 585 12 647 12 710 12 773 12 836 12 900 12 964 This table gives the saturation vapor pressure of moist air in kPa computed according to equation 3 10 Table 3 1 at 100 kPa total pressure Saturation Vapor Pressure Table B 1 Appendix C Psychrometric Charts Saturation Vapor Pressure at Vapor Pressure kPa Psychrometric Chart showing temperature vapor pressure and relative humidity 0 to 50 C Relative Humidity 100 100 Vapor Pressure at Tair amp 40 RH Dewpoint Air Temp Temp Tpp Tair 10 15 20 25 30 35 40 45 50 Temperature C 60 50 40 30 20 10 0 Psychrometric Charts 1 Appendix C Relative Humidity
10. Box 3 below Calibration 4 7 Section 4 Ill Calibrating for REM f you are going to be operating with an unknown concentration of gas flowing though the A cell there are two calibrations that you will need to Oper ations do periodically Calibrate Cell A initially and periodically thereafter The cell A calibration Box 4 below is critical to how REM works After that experience will tell you how often it needs to be redone the period might range from hours to days depending on conditions such as temperature 1 Point Match periodically Put the cell A gas through cell B to match the cells Box 1 below This counteracts drift and dirt effects 4 8 Calibration Section 4 Box 1 Box 2 One Point Match Two Point Match This procedure will match the cells at a single concentration The two point match will match the cells at a low and a high concentration The low concentration should be lt 20 umol mol for CO lt 3 mmol mol for H20 the high concentration should be near the upper end of where you are planning to operate cell A 1 Flow the target gas through cells A and B simultaneously Pressures temperatures and water concentrations should be the same Set both H20 and CO actions to Make cell B match cell A When stable press DoH20 After about 5 seconds the H5O readings for A and B should match Always do H50 first since the CO calculations depend on H20 being correc
11. CO H50 Infrared Gas Analyzer eese enne 4 12 Preliminary IN REFER MIR ND IRR RUE RI 4 12 Zero CO itcm med ect e e d eiui eite d EH RUE nai 4 14 Ba EQ quU 4 14 Span COD anie a ERE Reo ede t RAM EROR POE OP 4 14 NpruMiDorm C 4 15 Calibrating the LI 840 COj H50 Infrared Gas Analyzer eese eene 4 16 Calibrating the LI COR 11 6262 CO5 H50 Infrared Gas Analyzer eee 4 17 Preliminary coe Reo o P E HERE P ERREUR Ctt RO re ER 4 17 Absolute Mode H5O Zero Calibration 4 18 Absolute Mode H5O Span Calibration 0 0 cece eceseeeeecseeeeecseeaecsseaecsecaecseceseeeeeseeeeseaeseeseaeeegs 4 18 Differential Mode H5O Zero Calibration essere enne 4 19 Precautions ede Rete ge eei nee eret traen RP ed 4 19 Calibrating the LI COR 11 1600 Steady State Porometer RH Sensor sss 4 20 Initial Set p i oie Ro a e ed e e ERI e ttn 4 20 Calibration Setting the Zero inse eR eh PT IRR ERR 4 21 Calibration Setting the Span se D HEU DR RECIEN erae PR Pii 4 22 Check Intermediate Values eite RO RUE RE UE UON RED IM RETE Ripe dS 4 23 Calibrating the LI COR LI 6200 or LI 6000 Portable Photosynthesis System RH Sensor 4 24 Precalibration nie ette eedem eei ti nc an eura d 4 24 Calibration Setting the Z ro onse tette egi ete rete uns 4
12. CO H5O Analyzer Instruction Manual of LI COR 1990 can be converted to the form saturation vapor pressure at temperature T e T a x 10lbT c D This equation Table 3 1 equation 3 12 gives good accuracy from 50 C to 50 C and can be solved for either saturation vapor pressure e T or temperature T It is used in the LI 6262 to compute the dew point temperature from vapor pressure 3 6 Operation Section 3 Moist Air The saturation vapor pressure of water vapor in air is slightly different from that of pure water vapor It is a function of temperature as well as a weak function of total pressure Buck 1981 presents several equations with varying degrees of complexity and accuracy that are fit to recent data relating saturation vapor pressure of moist air over water and ice to temperature and pressure Wexler 1976 1977 Hyland 1975 Generally these equations have the form e T P a f T P e The pressure dependence is described by a multiplier called the enhancement factor f T P The enhancement factor is defined as the ratio of the vapor pressure of moist air to that of pure water vapor Buck 1981 both at the same temperature It is primarily a function of pressure but the most detailed formulations also include a weak temperature dependence Buck 1981 Adequate accuracy results if the enhancement factor is given a constant value of 1 004 Table 3 1 for barometric pressures above 80 kPa and temperatu
13. LI 610 on the hose leading from the AIR IN fitting as shown in Figure 5 1 Before installing a new filter blow clean dry air through it to remove any fibers or other debris that may be loose inside The old filter can be easily removed by pressing the red ring toward the center of the connector and pulling it off of the filter Leave the connector attached to the hose as repeated removal from the hoses may result in a leak The filters may also be removed by inserting a pair of long nose pliers between the coupling and the filter gently pry the two apart z O 7 21 lt a Install the new filter with the white directional arrow facing away from the AIR IN fitting Figure 5 1 Spare filters can be ordered from LI COR under part number 300 01961 1 each 5 2 Maintenance Section 5 Condenser Fill Drain Port Air Input Internal Water Filter Screen Radiator Fill Internal Air Filter Figure 5 1 11 610 interior Internal Water Filter Screen A wire mesh filter screen is present on the internal side of the TO COOLER fitting Figure 5 1 This screen should be checked monthly as a clogged screen can severely limit the flow of cooling water through the system To clean the internal water filter screen Remove the cover of the LI 610 to gain access to the filter screen The radiator does not need to be drained to clean the filter screen Place a towel under the large hose internal to
14. Mg ClO4 2 between the 11 610 and the sensor housing Alternatively one could use a tank of compressed air as the source of dry air however it may still be desirable to use a desiccant between the tank and the sensor housing especially if the tank pressure is low 4 26 Calibration Section 4 Calibration Setting the Span Allow dry air to flow through the sensor housing for about 60 minutes Identify the zero potentiometer again and adjust so that the display reads 0 7 RH Remove the Mg ClO4 2 from the air line connecting the LI 610 to the sensor housing Note the sensor chamber temperature Te from the console key TCHAM Find the dew point temperature Tg that corresponds to 80 at the cuvette temperature using the psychrometric graph provided For example to obtain 80 at Te 25 C set Tg 21 3 Flow air from the LI 610 through the sensor chamber for about 60 minutes At the end of this time period note the chamber temperature Te and the 11 610 dew point temperature Compute the exact RH to which the span should be set This can be done using equation 4 1 A pressure correction must be applied when the vapor pressure is established in the dew point generator condenser at an elevated pressure and measured in the calibration block at atmospheric pressure Equation 4 1 gives the relative humidity in the calibration block at temperature T and pressure P assumed atmospheric when it is
15. acetic acid using the syringe or small squeeze bottle included Fill until the acetic acid rises in the fill drain tube and is approximately 1 cm below the top of the condenser housing Rinse the syringe and or squeeze bottle with 5 4 Maintenance Section 5 Fuses distilled water thoroughly 4 5 times to remove any residual acetic acid Allow the acetic acid to soak in the block for about 10 15 minutes To drain the block plug the output ports on the instrument front panel or use the syringe to draw the acid out Turn the air pump ON and open the flow adjust valve slightly the acid will drain through the hose attached to the fill drain fitting CAUTION Be sure that the hose attached to the fill drain fitting is directed away from your face Acid will squirt for a considerable distance if the air pump is turned on with the flow adjust valve substantially open Fill with distilled water drain and repeat 4 5 times to thoroughly clean the condenser block The 6 amp fuse in the holder on the back panel protects the 10 5 16 VDC battery circuit The 1 amp slow blow fuse protects the 610 01 AC Module that is used with 100 130 200 260 VAC line voltage If the LI 610 fails to turn on check the fuse for the power source you are using battery or AC If the Dew Point Generator continually blows fuses it is in need of repair Replacing the Air Pump Diaphragm The air pump diaphragm may fail from pressure surges or from prolonge
16. customer to make such repairs as covered by this limited warranty Further information concerning this warranty may be obtained by writing or telephoning Warranty manager at LI COR inc IMPORTANT Please return the User Registration Card enclosed with your shipment so that we have an accurate record of your address Thank you LI COR inc 4421 Superior Street Box 4425 Lincoln Nebraska 68504 USA Phone 402 467 3576 FAX 402 467 2819 Toll free 1 800 447 3576 U S amp Canada envsales licor com www licor com
17. lk Revie Reeth 3 10 Relative ote eod p ic RR Pen re eoe eb ien eng e PERS 3 10 sample Calculations o oie ea dee DT RO Oe dea taie eet 3 11 Additional uei mre e ete ee ie re e DE REOR Ore dels 3 13 Water SOrptQn s d etico ee th t eee en dto eb Ja a gd tede eet 3 13 Maximum Flow R tes nornin ioti i re BAN e rhe eee e E e TREE ENT 3 13 Using the 610 03 Digital Pressure en nennen nene 3 16 Connecting the 11 610 and 610 03 to the 11 6200 RS 232C Port 3 18 RELETENCES MM dys 3 20 Section IV CALIBRATING LI COR INSTRUMENTS General Information onte p e E tee tiem tC Bene Mau sabes TE et re betonen 4 1 Calibrating the 11 6400 H20 Analyzer ener ener en enne en nennen eene tne 4 1 Setting the HO Span e Remote ere ir e te E tri e erret 4 1 Calibrating the LI 7000 CO2 H20 Infrared Gas Analyzer eese 4 4 Preliminaty ro EE REDE T RERO ORE Ed RE 4 4 Calibration Instructions ettet e rq A e eet e E tete eee 4 6 I Reference Cell A is Known and Constant esses seen 4 7 II Reference Cell A is Known but not Constant seen enne 4 7 III Calibrating for REM Operations nennen nennen nennen ener enne rennen 4 8 User Calibration Example 21a eite teu rem Ae Re bt e ees 4 10 Calibrating the LI 7500
18. 26 Calibration Setting the Sp n Pn enter e EORR IURE 4 27 Check Intermediate Values sinis siwi sa gag an ette deeds bee eee a a 4 28 Calibrating Relative Humidity Sensors General sess nennen 4 29 Calibrating Dew Point Hygrometers General eese enne een enne nee 4 29 Reterences ient a tes Rats shia PED eek ate Rid a eet hig cee dtes 4 29 Section V MAINTENANCE Draining the TOO eere dr dite ner HE Reed 5 1 Condenser BIOK a sako ra hU hr PRA C EHE ERR Ree 5 1 R diator Assembly Tae ht ED et t e P e e Rn 5 2 Internal Air or RR UR e 5 2 Internal Water Filter Screens Ne KG GANG EA NGANENGNENG cana enced ng KA GA Ga Aa 5 3 External Pan Eltern REESE EE tesa cach tunes GA GANG BA RENE EEUU Ia a aa 5 4 Cleaning the Condenset Block m ie ete tete i capes reet ntes 5 4 lu E 5 5 Replacing the Air Pump Diaphragm eese nenanem anan nenen en 5 5 Recharging the 6200B Battery lt tet t ir NEG ER EORR UR 5 7 Section VI TROUBLESHOOTING Appendix A Specifications Appendix B Saturation Vapor Pressure Table Appendix C Psychrometric Charts Appendix D LI 610 Calibration Traceability Warranty Section What s What Spa
19. 6 2 059 18 2 072 2 085 2 098 2 111 2 125 2 138 2 151 2 165 2 179 2 192 19 2 206 2 220 2 234 2 248 2 262 2 276 2 290 2 304 2 318 2 333 20 2 347 2 362 2 377 2 391 2 406 2 421 2 436 2 451 2 466 2 482 21 2 497 2 512 2 528 2 543 2 559 2 575 2 590 2 606 2 622 2 638 22 2 654 2 671 2 687 2 703 2 720 2 737 2 753 2 770 2 787 2 804 23 2 821 2 838 2 855 2 872 2 890 2 907 2 925 2 943 2 960 2 978 24 2 996 3 014 3 032 3 051 3 069 3 087 3 106 3 124 3 143 3 162 25 3 181 3 200 3 219 3 238 3 258 3271 3 296 3 316 3 336 3 356 26 3 376 3 396 3 416 3 436 3 456 3471 3 497 3 518 3 539 3 559 27 3 580 3 602 3 623 3 644 3 665 3 687 3 709 3 730 3 752 3 774 28 3 796 3 818 3 841 3 863 3 886 3 908 3 931 3 954 3 977 4 000 29 4 023 4 046 4 070 4 093 4 117 4 141 4 165 4 189 4 213 4 237 30 4 262 4 286 4 311 4 336 4 36 4 386 4411 4 436 4 46 4 487 31 4 513 4 538 4 564 4 590 4 617 4 643 4 669 4 696 4 722 4 749 32 4 776 4 803 4 831 4 858 4 885 4 913 4 941 4 969 4 997 5 025 33 5 053 5 082 5 110 5 139 5 168 5 197 5 226 5 255 5 285 5 314 34 5 344 5 374 5 404 5 434 5 464 5 495 5 525 5 556 5 587 5 618 35 5 649 5 680 5 712 5 743 5 775 5 807 5 839 5 871 5 904 5 936 36 5 969 6 002 6 035 6 068 6 10 6 135 6 168 6 202 6 236 6 270 37 6 305 6 339 6 374 6 409 6 443 6 479 6 514 6 549 6 585 6 621 38 6 657 6 693 6 729 6 765 6 802 6 839 6 876 6 913 6 950 6 988 39 7 025 7 063 7 101 7 139 7 178 7 216 7 255 7 294 7 333 7 372 40 7 412 7 451 7 491 7 531 7 57 7 612 7 652 7 693 7 734 7775 41 7 816 7 858 7 899 7 941
20. B reading will be matched to the H5O value of cell A Press the key f4 In the Actions box highlight Make cell A read and press OK Highlight Exact value and press OK Enter a target value of 370 and press OK Press the DoCO2 key f2 and wait for about 5 seconds Cell A will now read 370 umol mol Press the Calib key f4 In the CO Actions box highlight Make cell B match cell A and press OK Press the DoCO2 key f2 and wait for about 5 seconds Cells A and B will now read 370 umol mol Press Done f5 Calibration 4 11 Section 4 Calibrating the LI 7500 CO H 0 Infrared Gas Analyzer Preliminary To avoid condensation problems choose a dew point temperature that is about 3 to 5 C below the ambient temperature Also since water vapor sorbs and desorbs from surfaces allow plenty of time for the reading to stabilize It is important not to rush through the water vapor calibration If it is more convenient and water vapor zero and span calibrations can be done separately In general if reliable calibration standards are not available or if there is not enough time to do the job properly it is better to leave the zero and span settings alone than to rush through the procedure and make incorrect settings 1 Run the 2 7500 software program Select the Calibration tab in the Main Window of the 7500 50 Communications software 2 Place the calibration tube into the sensor head as shown
21. C with the probe and the resistance of the thermistor is measured at 49 90 C The thermistor is inserted into the condenser block again filled with water and air flowing and the LI 610 temperature display is set to 49 90 C The span potentiometer in the LI 610 is adjusted until the thermistor resistance is the same as it was when inserted in the calibration fixture Specifications Zero Set Point Ice Bath Resolution 0 0006 C using thermistor Accuracy 0 02 Noise 0 0015 C Repeatability lt 0 002 C Condenser Resolution 0 0006 C using thermistor Accuracy 0 03 Noise 0 002 C Repeatability lt 0 003 C Stability lt 0 01 C Span Set Point Calibration Fixture Resolution 0 0007 C using thermistor Accuracy 0 03 Repeatability lt 0 01 Condenser Resolution 0 0007 C using thermistor Accuracy 0 05 Noise lt 0 002 C Repeatability lt 0 003 C Stability lt 0 01 C D 2 Calibration Traceability Warranty Each LI COR inc instrument is warranted by LI COR inc to be free from defects in material and workmanship however LI COR inc s sole obligation under this warranty shall be to repair or replace any part of the instrument which LI COR inc s examination discloses to have been defective in material or workmanship without charge and only under the following conditions which are 1 The defects are calle
22. LI 610 Portable Dew Point Generator Instruction Manual LI 610 Portable Dew Point Generator Operating and Service Manual NOTICE The information contained in this document is subject to change without notice LI COR MAKES NO WARRANTY OF ANY KIND WITH REGARD TO THIS MATERIAL INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE LI COR shall not be liable for errors contained herein or for incidental or consequential damages in connection with the furnishing performance or use of this material This document contains proprietary information which is protected by copyright All rights are reserved No part of this document may be photocopied reproduced or translated to another language without prior written consent of LI COR Inc Copyright 1991 LI COR Inc Printing History New editions of this manual will incorporate all material since the previous editions Update packages may be used between editions which contain replacement and additional pages to be merged into the manual by the user The manual printing date indicates its current edition The printing date changes when a new edition is printed Minor corrections and updates which are incorporated at reprint do not cause the date to change Ist Printing August 1991 2nd Printing November 2004 Publication Number 984 06659 August 1991 LI COR Inc 4421 Superior Street e Lincol
23. TD is corrected electronically A precision thermistor is used to calibrate the condenser block at 0 C and 49 90 C as it offers much greater sensitivity than the RTD The precision thermistor used to calibrate the RTD must first be calibrated so that its resistance is known at 0 C and 49 90 C An ice bath made according to NIST procedures is used to calibrate the thermistor at 0 C With the condenser block full of water and air flowing through it at approximately 2 liters per minute the LI 610 temperature display is set to 0 00 C The thermistor is inserted into the condenser block and the zero potentiometer in the LI 610 is adjusted until the resistance of the thermistor is the same as that recorded when it was in the ice bath A solid copper temperature controlled calibration fixture in conjunction with a NIST traceable 10002 precision platinum RTD probe is used to calibrate the thermistor at 49 90 C A NIST traceable 100Q standard Calibration Traceability D 1 Appendix D resistance is first provided to calibrate the ohmmeter which is used to measure the RTD probe The probe is then checked at 0 C using the ice bath described earlier Since the output of the probe is nearly linear and the ratio of the probe resistance at 49 90 and 0 C is inherently very stable any offset in the output of the probe noted at 0 C can be used to correct the measurement at 49 90 C The calibration fixture is then set to 49 90
24. adiator fill cap on the top of the LI 610 instrument case Figure 2 1 The cap is not threaded and can be pulled straight up Use the plastic squeeze bottle included with the LI 610 to add distilled or deionized water to the radiator reservoir until the water level is visible in the fill tube Connect the LI 610 to your power source AC or battery Turn the power switch ON Turn the COOLER switch ON moment arily to flow water through the water pump and radiator assemblies Shut the LI 610 off and continue to fill the reservoir in this manner until the water level remains visible in the fill tube The radiator assembly requires approximately 200 ml of water to completely fill to this level TO PREVENT PERSONAL INJURY DISCONNECT THE LI 610 FROM AC POWER WHEN FILLING THE RADIATOR ASSEMBLY At this time add 15 20 drops 2 ml of algicide included with the LI 610 to the radiator reservoir Replace the radiator fill cap If you plan to store the LI 610 in freezing conditions drain the radiator and condenser block assemblies completely To operate the LI 610 in freezing conditions fill the radiator assembly not the condenser with a mixture of ethylene glycol one formulation of which is commonly called Pre Operation 2 1 Section 2 antifreeze A 50 50 mixture of ethylene glycol water will protect the radiator from freezing to approximately 40 C ie Ethylene glycol is the recommended antifreeze do not use propy
25. al No such table exists for the LI 6000 If you encounter this problem with the LI 6000 it may be desirable to adjust the span to read a little high if intermediate values are consistently low It is unlikely that intermediate values will be consistently high For example if an intermediate value corresponding to an actual RH of 56 reads 52 try setting the span to 81 etc However keep in mind that RH errors at high humidities have larger effects on conductance measurements than those at intermediate humidities 4 28 Calibration Section 4 Calibrating Relative Humidity Sensors General The LI 610 can be used to calibrate a wide variety of relative humidity sensors in much the same manner as described earlier for calibrating the humidity sensors in the LI 1600 and LI 6200 There are many types of relative humidity sensors in principle they can be calibrated with the LI 610 if certain basic procedures are followed First the sensor should be enclosed in a chamber so that the LI 610 can provide a constant source of water vapor to the sensor Secondly the temperature of the chamber which houses the sensor must be monitored to accurately gauge the relative humidity present See Sample Calculation 1 page 3 10 for an example of how to perform a calibration for a relative humidity sensor Follow the manufacturer s recommendations for making any adjustments i e potentiometers necessary for calibrating your particul
26. anged 1 The 6200B Rechargeable Battery and the 610 01 AC Module both fit into the compartment on the back of the LI 610 Loosen the two thumbnuts and lift the right side of the retaining strap to access the compartment Place the 6200B in the compartment and replace the retaining strap See Table 2 1 for the approximate battery life of the 6000B and 6200B batteries when used with the LI 610 2 If you are installing the 610 01 remove the retaining strap Install the AC Module and replace the retaining strap Tighten the thumb 2 4 Pre Operation Section 2 WARNING nuts securely Connect the power cord to one of the connectors labeled 10 5 16 VDC on the rear panel Table 2 1 Hours of Battery Life for 6000B and 6200B Batteries 25 C ambient Hours of Battery Life approximate Set Dew Point 6000B 6200B 2 5 2 75 5 0 5 5 2 0 2 25 4 0 4 5 1 50 1 75 3 0 3 5 When the battery voltage reaches approximately 10 3 10 4 volts the LOW BATT light on the instrument front panel Figure 2 3 will illuminate indicating that a system shutdown will occur if a charged battery is not connected Connect a fresh battery to continue operation the LOW BATT light will shut off Instructions for recharging the 6000B and 6200B batteries are given in Section 5 The LI 610 will shut down when the battery voltage reaches approximately 10 volts The Peltier coolers liquid pump air pump fan and display will turn off to con
27. ar humidity sensor Calibrating Dew Point Hygrometers General References As with relative humidity sensors the configuration of dew point hygrometers is widely variable We hesitate to recommend specific calibration procedures for dew point hygrometer heads with which we are unfamiliar In principle however the LI 610 can be used to provide moist air with a known dew point 0 2 C that can be used as a benchmark to test a dew point hygrometer Follow all manufacturer s recommendations for further calibration procedures Buck A L 1981 New equations for computing vapor pressure and enhancement factor J Appl Meteor 20 1527 1532 McDermitt D K 1990 Sources of error in the estimation of stomatal conductance and transpiration from porometer data HortScience 25 12 1538 1548 Calibration 4 29 Section V Draining the LI 610 Condenser Block Maintenance The LI 610 should be completely drained before being shipped or stored for long periods of time This will prevent the possibility of freezing algal growth chemical corrosion etc To drain the condenser block Remove the threaded capnut attached to the fill drain tube on the top of the condenser block assembly e Attach a male Luer lock to the fill drain fitting on the condenser block Connect a short section of Bev a line tubing with a female Luer lock included to the male Luer lock on the condenser block housing Thread the female L
28. arometric pressure The span of all LI COR infrared gas analyzers will vary with barometric pressure changes because infrared absorptance varies with pressure Therefore an electronic barometer should be used to provide accurate barometric pressure data to the LI 6262 or other analyzer if continuous recordings of CO and or H O vapor concentrations over long periods of time are required Note also that some zero shift can be expected with changes in analyzer temperature Pressure in the analyzer optical bench varies with gas flow rate It follows that span settings should be made at the same flow rate as measurements whenever possible Further the calculations in the LI 6262 use the same pressure for both sample and reference cells Therefore flow rates and total pressures should be the same in the two cells In practice flow dependent over pressures in the sample and reference cells will be small when flows are low about 1 liter min or less and the analyzer is vented directly to the atmosphere However large pressure differences between the two cells that could occur with high flow rates gt 5 liters min cannot be accommodated by span adjustments on board calculations Presumably large pressure differentials between sample and reference cells could be included in calculations outside the L1 6262 but this has not been tested Calibrating the LI 1600 Steady State Porometer RH Sensor Initial Setup 1 Set the LI 610 dew
29. arrow keys TY adjust the values of G and G see Equations 14 5 and 14 6 on page 14 5 of LI 6400 Book 3 Calibration 4 1 Section 4 To set the H20 Span Setup the LI 610 for an appropriate dew point Subtract about 5 C from room temperature and use that for the target dew point temperature Wait until the condensor s temperature as monitored on the LI 610 reaches this target The reason for this 5 C buffer is to avoid condensation in the line between the LI 610 s condensor and the IRGA If condensation happens you will have large errors Set the flow rate Use a flow rate of about 0 5 1 min from the LI 610 Attach to the IRGA You have two choices as shown in Figure 4 1 We recommend option B splitting the flow and connecting both the reference and sample with Match Off The reason for this is that you will be able to drastically reduce the equilibrium time waiting for the sample cell If you connect only to the sample port then Match must be ON for the air to get to the reference analyzer as well If you split the flow Match can be Off By turning Match ON and Off while watching the reference concentration you can see the influence of the sam ple cell and chamber on the air stream Figure 4 1 Flow from the LI 610 can be connected only to the sample port of the LI 6400 sensor head A or can be split to both sample and
30. ate air streams which are supplied to OUTPUT 1 and OUTPUT 2 on the front of the instrument The rate of flow through these outputs is indicated by two rotameters on the front panel Flow is divided between the outputs using the flow control valve on output port 2 Operation 3 1 Section 3 Water Flow In the LI 610 Air Inlet Filter Pump Air Output a Port 2 Air Flow Path palea 1 1 Rotameter fei E DOORS Valve lt Rotameter m Air Output Stage 4 Condenser Peltier Cooler N Cooling Water Path Radiator Pump Reservoir Figure 3 1 Path of air and water flow through the LI 610 An internal radiator assembly is used in the LI 610 to provide a means of dissipating the heat generated by the two Peltier coolers attached to the condenser block Figure 3 1 The Peltier coolers are thermoelectric devices which absorb or liberate heat depending upon the direction of electrical current flow through the junction of dissimilar metals When the coolers are switched ON current flows in a direction which causes heat to be absorbed or generated based on the position of the TEMPERATURE SET controls on the front panel thereby lowering or raising the temperature of the water present in the block The condenser blocks are copper which is an excellent conductor of thermal energy A continu
31. ating the LI 6200 or LI 6000 Portable Photosynthesis System relative humidity sensors and the LI 1600 Steady State Porometer relative humidity sensor 610 04 BNC mV Leads for connecting to either the Analog Output or Command Input fittings on the LI 610 front panel one set included with the LI 610 One set is included a second set is required if you wish to use the Analog Output and Command Input functions simultaneously 6200B Rechargeable Battery 10 5 16 VDC The 6200B Recharge able Battery is tested and fully charged before it leaves the factory but may discharge during shipping It is a good idea to test your battery to make sure that it is charged If the battery is below 12 volts it should be charged before use Refer to Section 5 for charging instructions The 6200B requires the LI 6020 Battery Charger for recharging Never store batteries in a discharged state Charge stored batteries every three months LI 6020 Battery Charger 92 138 184 276 VAC 47 to 63 Hz Battery Leads for connection to a user supplied battery 10 5 16VDC or other DC power supply 1 2 Unpacking amp Initial Inspection Section Set Up Filling the Radiator Pre Operation Two distinct systems must be filled with distilled or deionized water before operating the radiator assembly located within the LI 610 case and the condenser block assembly located externally To fill the radiator assembly remove the black r
32. ative values If you are using a compressed air tank and the display reads zero adjust the potentiometer until the display shows a small positive number and then turn the potentiometer down until the display reads zero and the null meter is centered 1 Remove the Mg ClO 4 or silica gel tube from the air line connecting the LI 610 to the LI 1600 2 Note the 11 1600 cuvette temperature on the LI 1600 console display 3 Find the dew point temperature Tq that corresponds to 80 RH at the cuvette temperature T using the psychrometric graph provided For example to obtain 80 RH at T 25 C set Tg 21 3 C 4 Flow the air from the LI 610 through the cuvette for about 60 minutes At the end of this time period note the cuvette temperature Te and 11 610 dew point temperature 5 Compute the exact RH to which the span should be set If the vapor pressure is generated at an elevated pressure as occurs in the dew point generator condenser a pressure correction must be applied when vapor pressure is measured at atmospheric pressure The relative humidity in the LI 1600 cuvette at temperature and 4 22 Calibration Section 4 Check Intermediate Values pressure P assumed atmospheric when supplied with air generated at dew point and pressure P AP is given by 17 502T P 2409747 _ P AP RH aT 100 240 97 4 1 Adjust 11 1600 span potentiometer see Section 5 o
33. bligation of LI COR inc expressly set forth herein LI COR inc disclaims all warranties of merchantability or fitness for a particular purpose The foregoing constitutes LI COR inc s sole obligation and liability with respect to damages resulting from the use or performance of the instrument and in no event shall LI COR inc or its representatives be liable for damages beyond the price paid for the instrument or for direct incidental or consequential damages The laws of some locations may not allow the exclusion or limitation on implied warranties or on incidental or consequential damages so the limitations herein may not apply directly This warranty gives you specific legal rights and you may already have other rights which vary from state to state All warranties that apply whether included by this contract or by law are limited to the time period of this warranty which is a twelve month period commencing from the date the instrument is shipped to a user who is a customer or eighteen months from the date of shipment to LI COR inc s authorized distributor whichever is earlier This warranty supersedes all warranties for products purchased prior to June 1 1984 unless this warranty is later superseded DISTRIBUTOR or the DISTRIBUTOR S customers may ship the instruments directly to LI COR if they are unable to repair the instrument themselves even though the DISTRIBUTOR has been approved for making such repairs and has agreed with the
34. cessary to minimize the flow related pressurization of the LI 610 condenser Check for condenser pressure changes Turn off the flow and open the condenser fill drain tube port Note the location of the fill tube water meniscus Turn on the flow regulate the flow to the recommended level and measure the change in meniscus height CAUTION Water will squirt out of the fill tube if the LI 610 pumps against a lot of back pressure at high flow rates It may be necessary to put a vertical extension tube on the fill drain port and or reduce the flow rate accordingly Calibration 4 21 Section 4 Calibration Setting the Span Calculate the flow dependent condenser pressure as AP 0 0979 kPa x water column height in cm This pressure factor will be used later 3 The LI 610 should be generating a dew point of 0 05 C The air stream water vapor pressure will be about 0 61 kPa Any remaining water vapor can be removed by placing a tube of freshly dried silica gel oven dry at 175 C for 1 hour or anhydrous Mg CIO4 between the LI 610 and the LI 1600 sensor head Alternatively one could use a tank of compressed air or nitrogen as the source of dry air 4 Allow this dry air to flow through the LI 1600 cuvette chamber for about 60 minutes Adjust the zero potentiometer so the display reads 2 RH if silica gel is used or 0 if Mg ClO4 2 compressed air or nitrogen is used The LI 1600 will not display neg
35. conds condensation in the radiator housing and an inability for the instrument to maintain the chosen dew point See Section 5 Internal Water Filter Screen for instructions on how to clean the water filter screen In some cases the LI 610 may be able to achieve a temperature setpoint above the ambient temperature but is not able to achieve a setpoint below ambient This problem can be caused by a variety of problems 1 Radiator and coolant reservoir are empty 2 Coolant pump is off or not functioning properly 3 Blockage in cooling water path 4 Peltier coolers not receiving proper voltage First make sure the radiator contains coolant water should be visible in the radiator fill tube Check to make sure that the coolant pump is working properly Disconnect the To Cooler line power on the LI 610 and briefly toggle the COOLER switch to the ON position If the pump is working properly water will discharge from the To Cooler port If water does not discharge contact LI COR Check for a blockage in the cooling water path Without coolant circulating through the Peltier coolers to dissipate heat they cannot achieve a temperature target below ambient There are two Peltier coolers one on each side of the condenser block There are water lines that connect the two coolers and also run to and from the radiator A blockage can occur in any of the hose fittings that connect to the Peltier coolers To remove the blockage di
36. d on before any voltages can be read Edit the E2 Sensor List Press FCT E2 Scroll down until 08 OFF appears on the top display line and press EDIT Enter LOW or just L in response to the first NEW prompt and enter the label TD in response to the second NEW prompt This causes the LI 610 output voltage to be available in channel 08 with low 12 bit 3 18 Operation Section 3 resolution We shall convert it to temperature in the E3 List The display will read 08 LOW TD Now place 09 OFF on the top display line and press EDIT Change the display to read 09 HIGH PR using the same procedure as above High resolution is needed for the 610 03 because of its low output voltage 1 mV mb The E3 System Program must be expanded to compute the incoming vapor pressure from LI 610 and 610 03 input voltages The computing algorithm will read the LI 610 input voltage divide it by 100 to compute the dew point temperature calculate saturation vapor pressure at the dew point temperature and finally correct for pressure It is not necessary to convert the 610 03 input voltage to pressure because the correspondence is already one to one Press FCT E3 Scroll down to an unused channel say channel 1B Press EDIT Enter the label EIN in response to the first NEW prompt and press RTN Now enter the following program without spaces 08 C2 65 74 AO 64 09 AO 62 65 Constant C2 is 100 AO is barometric pressure a
37. d operation If the pump motor appears to be functioning normally but the rate of air flow is greatly reduced it may be an indication that the diaphragm has failed A replacement Brailsford air pump diaphragm is included in your spare parts kit A pump that is functioning normally will generally output a pressure of 450 to 600 mb when measured directly at the TO CONDENSER port with the 610 03 Digital Pressure Meter Spare diaphragms can be ordered from LI COR under part number 247 03536 1 each Maintenance 5 5 Section 5 Slotted Screws Dust Cover 1 ZS Diaphragm Connecting Rod To replace the diaphragm Remove the LI 610 top cover It is generally not necessary to remove the air hoses from the inlet and outlet ports on the pump head Unscrew the four slotted screws and remove the pump head Hold the connecting rod unscrew the single flat head screw and remove the old diaphragm Place a small amount of the grease provided along the edge of the new diaphragm Move the connecting rod to the bottom of its stroke and hold it while installing the new diaphragm The diaphragm must be properly centered by the plastic retaining washer Screw the flat head screw down snug Reinstall the dust cover Reinstall the pump head Make sure that the rim of the new diaphragm is correctly seated
38. d to the attention of LI COR inc in Lincoln Nebraska in writing within one year after the shipping date of the instrument 2 The instrument has not been maintained repaired or altered by anyone who was not approved by LI COR inc 3 The instrument was used in the normal proper and ordinary manner and has not been abused altered misused neglected involved in and accident or damaged by act of God or other casualty 4 The purchaser whether it is a DISTRIBUTOR or direct customer of LI COR or a DISTRIBUTOR S customer packs and ships or delivers the instrument to LI COR inc at LI COR inc s factory in Lincoln Nebraska U S A within 30 days after LI COR inc has received written notice of the defect Unless other arrangements have been made in writing transportation to LI COR inc by air unless otherwise authorized by LI COR inc is at customer expense 5 No charge repair parts may be sent at LI COR inc s sole discretion to the purchaser for installation by purchaser 6 LI COR inc s liability is limited to repair or replace any part of the instrument without charge if LI COR inc s examination disclosed that part to have been defective in material or workmanship There are no warranties express or implied including but not limited to any implied warranty of merchantability of fitness for a particular purpose on underwater cables or on expendables such as batteries lamps thermocouples and calibrations Other than the o
39. e Photosynthesis System Humidity Sensor Precalibration 1 Set the LI 610 dew point to 0 05 2 Mount the LI 6200 or 11 6000 sensor housing in a vise if possible Unhook the leaf temperature thermocouple from the monofilament support lines and then remove the chamber from the sensor housing Ue BE VERY CAREFUL NOT TO TOUCH SCRATCH OR SMOKE NEAR THE EXPOSED HUMIDITY SENSOR 3 Check to be sure that the sensors and the exposed parts of the sensor housing are clean and free of debris 4 Attach the nickel plated aluminum block included in the 610 02 RH Calibration Accessory Kit to the sensor housing Figure 4 6 and tighten it down Allow the leaf temperature thermocouple to hang free outside the aluminum block The sensor head O ring will seal around the thermocouple wires sufficiently well to prevent serious leaks 4 24 Calibration Section 4 Sensor Housing Figure 4 6 Nickel plated aluminum block attached to LI 6200 or LI 6000 sensor housing 5 Remove the top plate from the sensor housing by removing the four corner screws Locate the zero and span potentiometers in the LI 6200 or LI 6000 sensor housing as shown in Figure 4 7 below RH ZERO RH GAIN Figure 4 7 Location of the zero and span potentiometers in the LI 6200 or LI 6000 sensor housing 6 Disconnect the two Bev a line hoses from the barbs protruding from the sensor housing and connect one end of a 12 300 mm length of 1 8 3 17 m
40. e condenser block is overfilled simply use the syringe to draw some water out of the fill drain tube Fill the syringe with air after filling the condenser block with water and syringe the air into the fill tube to remove any water which may adhere to the side of the tube This adhesion can cause a false water level reading in the fill tube if it is not purged Check the water level reading in the fill drain tube and repeat if necessary After filling to the proper level replace the threaded capnut It is recommended that the distilled water in the condenser block assembly be changed every 2 days with continuous use The water level in the condenser should be monitored closely particularly if the temperature and water vapor content of the input air stream is significantly different than the LI 610 set dew point In this case water vapor will either condense out of the input air stream thereby raising the water level in the condenser or evaporate out of the condenser into the output air stream lowering the condenser water level The condenser water may need to be changed more frequently if the input air stream contains at levels higher than 500 ppm LI COR has found that high levels cause the formation of precipitates within the condenser block which can cause the water to foam leading to unstable flow rates If the rotameter gauge s fluctuates erratically it may be an indication that the condenser water needs to be ch
41. equations 3 4 and 3 6 and solving for device temperature 240 97 In R f T 3 9 17 502 In R T where T the pressure corrected dew point temperature in the measuring device given the 11 610 dew point temperature setpoint T4 R P P AP and KT 17 502T 240 97 T Water vapor adsorbs to the surface of all materials Therefore be sure to allow ample equilibration times when calibrating humidity measuring instruments especially when large humidity changes are made Equilibration times on the order of an hour are not excessive when performing careful calibrations Our initial tests suggest that 2 liters per minute is about the maximum flow rate that can be used with the LI 610 and still obtain complete saturation at ordinary laboratory temperatures Tests continue to further define the limits of instrument operation Operation 3 13 Section 3 Relative Humidity 100 90 80 Saturation Vapor Vapor Pressure lt Pressure 70 at Typ at Tair amp 40 RH 0 e e T i 50 60 Dewpoint Air Temp Temp Tair 50 40 Vapor Pressure kPa 30 20 0 0 5 10 15 20 25 30 35 40 45 50 Temperature C Figure 3 2 Psychrometric Chart showing temperature vapor pressure and relative humidity 3 14 Operation Section 3 Table 3 1 Reference vapor Vapor pressure kPa Temperature C computed pressure kPa computed from temperature C from vap
42. etailed instructions for connecting the LI 610 to the LI 6200 Portable Photosynthesis System are given on pages 3 16 to 3 19 along with a discussion of the 610 03 Digital Pressure Meter Theory of Operation Ideal Gas Laws When a gas stream passes through the LI 610 condenser water vapor is added or removed so that the exiting gas stream is saturated at the condenser temperature In most cases that gas stream will be air so we shall consider a description of moist air Atmospheric gases at pressures near ambient conform closely to the ideal gas law The partial pressure of an ideal gas is given by p V njRT 3 1 where is the partial pressure of gas component i kPa V is volume m3 n is the number of moles of gas component i is the universal gas constant 0 008314 m kPa mol K and T is absolute temperature K Dalton s Law of partial pressures states that the total pressure P of an ideal gas mixture equals the sum of the component partial pressures For moist air P pjte 32 where X is the sum of partial pressures of dry air components also expressed as P and e is the partial pressure of water vapor Therefore P P e The partial pressure of water vapor may also be expressed as a mole fraction The mole fraction X of a component j in a mixture or solution is defined as X Combining equations 1 2 with the definition of mole fraction it can be shown
43. f 11 1600 Manual for location of the span potentiometer until the display reads RH within 0 4 RH The display resolution is 0 4 so don t be concerned if you cannot match the sensor display with the incoming RH beyond this level of precision EXAMPLE If the cuvette temperature T is 24 C the dew point temperature Tg is 21 C and the change in condenser pressure between no flow and the actual flow is 3 cm of water at a barometric pressure of 100 kPa then equation 4 1 becomes _ 0 997e 4 RH B e 15853 x 100 83 1 Conduct the following procedures without further adjustment to the span potentiometer 1 Find the dew point temperature that corresponds to about 50 RH at ambient temperature using the psychrometric charts in Appendix C Set the LI 610 to the dew point temperature and allow 60 minutes to elapse after Tg is reached Calculate the exact cuvette RH using equation 4 1 and compare the result to the displayed RH They should agree to within 3 RH Reset the LI 610 to a dew point corresponding to about 20 RH Repeat steps 2 and 3 Repeat the calibration procedure if there is a deviation of greater than 3 RH If you find that intermediate RH values read consistently low set the span RH 1 higher than the calculated value For Calibration 4 23 Section 4 example if the span RH is actually 80 set the span to 81 and repeat steps through 4 Calibrating the LI 6200 or LI 6000 Portabl
44. ference Cell A Is Known and Constant Il Reference Cell A Is Known but not Constant differential value will be more accurate than either individual cell s accuracy The calibration instructions for these three operating modes are described next If you will be flowing a known constant concentration gas though the A cell there are two user calibrations that you may want to do 1 Point Match periodically Put the cell A gas through cell B to match the cells Box 1 below This counteracts drift and dirt effects Span optional Put a known concentration and different from cell A in cell B and calibrate Box 3 below If during operation cell A will have a range of known concentrations a potential problem with common mode drift arises This can be minimized by adding a 2 Point Match to the list of calibrations Note that during any calibration the cell A and B concentrations must be stable 2 Point Match initially Match first with scrubbed air in both cells then again with a typical cell A concentration in both cells Box 2 below This will characterize the common mode drift in order to minimize the effect on matching of a changing reference concentration 1 Point Match periodically Put the current cell A gas through cell B to match the IRGA Box 1 below This counteracts drift and dirt effects Span optional Put a known concentration different from cell A in cell B and calibrate
45. from porometer data HortScience 25 12 1538 1548 Wexler A 1976 Vapor pressure formulation for water in the range 0 to 100 C J Res Natl Bur Stand 80A pp 775 ff 3 20 Operation Section IV Calibrating LI COR Instruments General Information The LI 610 can be used to calibrate water vapor gas analyzers such as the LI COR 11 6262 11 7000 11 7500 and LI 840 CO5 H50 Gas Analyzers the gas analyzer in the LI 6400 Portable Photosynthesis System and instruments that use relative humidity sensors including the LI COR LI 1600 Steady State Porometer and the LI 6000 and LI 6200 Portable Photosynthesis Systems among others The LI 610 can also be used to verify the calibration of dew point hygrometers An article written by LI COR Applications Scientist Dayle McDermitt HortScience Dec 1990 discusses a variety of topics concerning stomatal control of leaf conductance including the effects of sensor or calibration errors on the accuracy of conductance measurements the relationship between molar conductance units presently used and velocity units used in older literature as well as other considerations Reprints of this article are available on request from LI COR Calibrating the LI 6400 H O Analyzer Setting the H20 Span To check the span of the H5O analyzer you ll need a known concentration of H20 provided by the 11 610 The H20 IRGA gain adjustment is a process by which the user can manually using the
46. he following example One way to express the enhancement factor is f T P 1 00072 3 2 x 10 P 5 9 x 10 PT dimensionless 3 5 Buck 1981 Five kPa is a typical condenser over pressure that might occur if a high flow rate 1 5 liters is supplied to a gas exchange system downstream from the LI 610 At 20 C and P 100 kPa f T P 1 0039 at 20 C and P 105 kPa f T P 1 0041 a negligible difference It is apparent from equation 3 5 that the enhancement factor temperature and pressure dependence causes only small deviations from the nominal value of 1 004 under normal conditions f T P varies from 1 0033 to 1 0043 over a pressure range of 80 kPa to 110 kPa and a temperature range of 0 C to 50 C However a 5 kPa over pressure in the condenser will have a much larger effect on the vapor pressure measured downstream if the measuring instrument is at atmospheric pressure To demonstrate this assume that the downstream vapor pressure is measured in the 11 6262 CO 2 H 20 Analyzer at 100 kPa total pressure while the water vapor mole fraction was established in the LI 610 at 105 kPa The water vapor mole fraction that was established in the LI 610 will be constant throughout the system if there are no sources or sinks between the LI 610 and the measuring instrument Let the subscript 610 denote variables established in the LI 610 and the subscript meas denote variables measured in whatever instrument is used e g
47. ield when completed Repeat for the H20 channel using the LI 610 to provide the airstream with known dew point Calibrating the LI 6262 CO H O Infrared Gas Analyzer Preliminary If present remove the blue Balston filters from inside the LI 6262 and replace them with the Gelman disc filters supplied in the spare parts kit The Gelman filters will not fit inside the LI 6262 case they must be placed in the airstream just before it enters the analyzer Under no circumstances should the LI 6262 be operated without filtering the air before it enters the analyzer The protocols suggested here for setting zero and span assume that high accuracy is desired so they have long equilibration times Experience with CO analyzers causes one to expect rapid and stable responses to changes in gas concentration however this will not be the case with water vapor Working with water vapor presents difficulties due to water vapor sorption that are not encountered with CO These problems will cause the LI 6262 to appear to drift or respond slowly to changes in humidity The resolution of the LI 6262 is beyond that obtainable with most other humidity measuring instruments even dew point hygrometers so very small humidity changes can now be seen which in the past were largely unobservable High sensitivity coupled with water sorption temperature variations pressure effects etc may cause complete stability to be elusive We suggest therefore that yo
48. in Figure 4 4 and connect the temperature sensor cable to the LI 7500 control box Figure 4 4 Flow calibration gas at the Air In port shown 4 12 Calibration Section 4 Insert the top of the fixture first and slide the bottom into place It is very important that the fixture is centered between the windows covering the source and detector modules It can be helpful to click on the Diagnostics tab in the 7500 50 software and view the AGC value while centering the fixture if the AGC value increases when the fixture is in place it indicates that one or both of the windows are partially or totally obscured Move the fixture back and forth until the AGC value reads the same value as before the fixture was inserted The fixture is very easy to center if it looks centered it probably is NOTE The three ports on the calibration tube are entirely interchangeable Click on the Calibration tab and verify that temperature and pressure sensors are working properly If you are using an alternate source for temperature and pressure values click on the Inputs tab and set that up IMPORTANT NOTE Always zero the instrument before spanning don t span then zero Flow CO free air through the calibration fixture at a rate of about 0 5 to 1 0 LPM Attach the zero gas to the calibration fixture at one of the ports shown in Figure 4 4 Calibration 4 13 Section 4 Zero Zero HO Span CO 5 Obse
49. in the matching groove on the underside of the pump head before tightening the four screws Turn the air pump on and block the outlet port on the pump head momentarily to form the new diaphragm Reinstall the air hoses and reassemble the LI 610 case 5 6 Maintenance Section 5 Recharging the 6200B Battery Make sure that the voltage selector slide switch on the back of the battery charger is set to appropriate line voltage 115 or 230 VAC Plug the charger into mains power The AC indicator light will illuminate The CHARGE indicator will illuminate if any of the batteries connected to the charger are being charged One method for testing a battery s charge is to connect it by itself into the charger If it is charged the CHARGE light will come on for only a few seconds If the CHARGE light illuminates with no batteries connected the AC voltage selector switch on the back is in the wrong position A fully discharged 6200B battery will require about 4 hours to recharge Four discharged batteries connected simultaneously would require 16 hours to recharge Maintenance 5 7 Section VI Instrument Can t Maintain Dew Point Instrument Can t Achieve Setpoint Below Ambient Temperature Troubleshooting This section summarizes some things that might go wrong and suggests what to do about these problems should they occur A dirty water filter screen can cause the LI 610 to produce a squeaking noise every few se
50. l unequilibrated air from the sample cell enters the reference cell When it stabilizes 30 seconds set the sample IRGA to read that value 10 Quit and Save if done Press escape and select View Store Zeros amp Spans now if you are done calibrating Calibrating the LI 7000 CO H O Infrared Gas Analyzer Preliminary To avoid condensation problems choose a dew point temperature that is about 3 to 5 C below the ambient temperature Also since water vapor sorbs and desorbs from surfaces allow plenty of time for the reading to stabilize and minimize the surface area it has to absorb on minimize tubing lengths It is important not to rush through water vapor calibrations give the surfaces plenty of time to equilibrate to large changes The LI 7000 provides two convenient user interfaces for doing user calibrations Figures 4 2 and 4 3 User Calibration CO2Aum m 8 CO2Bum m LAU 13 1 5 23 2 234 OR C02 Action H20 Action Do Nothing edit NN Figure 4 2 11 7000 calibration function on instrument display 4 4 Calibration Section 4 m User Calibration Iof x C02 Calibration MH20 Calibratio H20 Action lt Do Nothing gt M CO2 Action lt Do Nothing gt F N Make cell read 0 Make cell read History Make cell B match cell Make cell B read 0 Make cell B read Do Nothina Reset to factory settings
51. lene glycol or other antifreeze mixtures Radiator Fill Figure 2 1 11 610 top view showing location of radiator fill cap 2 2 Pre Operation Section 2 Filling the Condenser Block EIS 990 9 a Syringe 01 g Female Luer Lock _ __ Bev a line Tubing Male Luer Lock The gold plated condenser block assembly requires approximately 20 to 25 ml of distilled water to function normally Follow these steps when filling the condenser block assembly Remove the plastic capnut located at the front left corner of the condenser block assembly see Figure 2 2 The condenser block can now be filled using the 30 ml syringe included in your spare parts kit Thread a female Luer lock included in the spare parts kit into the syringe and draw 20 25 ml of water into the syringe Attach a male Luer lock to the fill drain port on the LI 610 Connect the two Luer locks with a short section of 1 8 ID Bev a line tubing as shown at left Fill drain port Condenser block Figure 2 2 Location of the condenser block fill drain port Slowly add water to the condenser block if the block is properly filled the water level in the fill drain tube will read midway between the and Min marks on the condenser block ruler Fill or drain to Pre Operation 2 3 Section 2 Power On this level as needed If th
52. lution are the same as before however the pressure correction from equation 3 6 must be inserted at step 3 before proceeding e 23 2 820 kPa 2 The required chamber vapor pressure e 1 128 kPa 3 The LI 610 vapor pressure required to give a chamber vapor pressure of 1 128 kPa is computed by rearranging equation 3 6 meas P AP 610 So en IB EPH 1 IS CEPR 4 Finally compute the LI 610 dew point temperature as before using the vapor pressure from step 3 240 97z __ _ where z In 17 502 z 0 61365 In Idol 0 6290 0 61365 T 29 0 C To achieve the desired RH in the leaf chamber the LI 610 setpoint temperature must be a little higher than before to correct for expansion of the gas stream 3 12 Operation Section 3 Additional Relationships Water Sorption Maximum Flow Rates 1 Combining equations 3 4 3 6 and 3 7 17 5027 5 24097 3 8 _ P RH 17 502T x 100 e240 97 T where P barometric pressure AP condenser over pressure 11 610 dew point temperature and T measuring device temperature RH is the relative humidity that will hold in the measuring device at T and P when the LI 610 is set to Tg with over pressure AP 2 It is sometimes necessary to know the pressure corrected dew point in a measuring device given the LI 610 dew point temperature condenser pressure and barometric pressure This can be found by combining
53. m ID Bev a line tubing to one of the hose barbs either barb will work and the other end to one of the LI 610 output ports Calibration 4 25 Section 4 Calibration Setting the Zero 1 Make sure that the sensor housing cable is connected to the console the cable from the LI 6200 console to the LI 6250 IRGA need not be connected and turn on the console Set the LI 610 flow rate to approximately 0 2 to 0 3 liters per minute This low flow rate minimizes flow related pressurization within the LI 610 condenser To check for condenser pressure changes Turn off the flow and open the condenser fill drain tube port Note the location of the fill drain tube water meniscus Turn on the flow regulate the flow to the recommended level and measure the change in meniscus height Calculate the flow dependent condenser pressure as AP 0 0979 kPa cm x water column height in cm This pressure factor will be used later For the LI 6200 the humidity lookup table FCT 47 should match the values given on the factory calibration sheet The multiplier value FCT C7 should also read 0 024414 For the LI 6000 set the system parameters for use with a desiccant as follows WINT 0 WSLP 0 FLOW 0 RH IN 0 CORR RH Y The LI 610 should be generating a dew point of 0 05 C The air stream water vapor pressure will be about 0 61 kPa Remove the remaining water vapor from the air by connecting a tube of fresh anhydrous
54. n Nebraska 68504 402 467 3576 FAX 402 467 2819 Toll free 1 800 447 3576 U S amp Canada E mail envsales 1 www licor com TABLE OF CONTENTS Section UNPACKING AND INITIAL INSPECTION What s What nort tete resur OU EI Og 1 1 Optional Accessories eene et e eb Re SEN Bp ath 1 2 Section Il PRE OPERATION eot tede Oeo ote mem e ees 2 1 Billing the Radiator asana PP gi 2 1 Filling the Condenser Block 2 erret tete eti de tir eterni 2 3 Power eate E eee er RE eei e ae 2 4 Section Ill OPERATION General Description erronee edet iei teet e etre re etd 3 1 Air Flow Through the LI 610 on a a aa E GONG TAN Aa eene nennen nennen treten TIN E rennen rennen 3 1 Water Flow Inthe LOTO etc betreten ue a o etcetera e n 3 2 Operation cisco a iG Bush tt b ertet RABI As ate tea 3 3 Command Inp t 3 sages Ne pe cred ees Pe rp e EP eene eet e iP 3 4 Analog d ue nep eee dee p edet OE Pets 3 4 Theory OF Operation ih ien ete HER Uie p e eR NER Cei red exte e NA na ga 3 5 Ideal GasEa3wW 2 2 ena Ta anana gag a ea SOR ORE nahe BG MAR meten 3 5 Pure Water Vapot tr ent ten Pe RES 3 6 Mist Artes ana to IRE Ro aei e I ee Duos aa 3 7 Pressure EHeCtS eec eoe a ee ii eet et det e te e ERR 3 8 Temperature Bffects 2 ete eoe et ime Rah A Rati
55. nd 08 and 09 are the LI 610 and 610 03 input voltages respectively Functions 62 64 and 65 are add multiply and divide and function 74 computes saturation vapor pressure from temperature using Lowe s equation See the Technical Reference Manual for more details about programming the LI 6200 Operation 3 19 Section 3 References 25 pin RS 232C Port 131211109 8 765 4 3 2 1 Jumper 25 24 23 22 21 20 19 18 17 16 15 14 black red black red 610 03 LI 610 Figure 3 3 Connection of the 610 03 and LI 610 to the LI 6200 25 pin RS 232C port shown connected to spare input channels and 2 Buck A L 1981 New equations for computing vapor pressure and enhancement factor J Appl Meteor 20 1527 1532 Goff J A and S Gratch 1946 Trans Amer Soc Heat and Vent Eng Vol 52 p 95 Hyland R W 1975 A correlation for the second interaction virial coefficients and enhancement factors for moist air J Natl Bur Stand T9A 551 560 LI COR inc 1990 LI 6262 CO2 H20 Analyzer Instruction Manual Publication No 9003 59 LI COR inc List R J 1966 Smithsonian Meteorological Tables 6th rev ed The Smithsonian Institution 527 pp Lowe P R 1977 An approximating polynomial for the computation of saturation vapor pressure J Appl Meteorol 16 100 103 McDermitt D K 1990 Sources of error in the estimation of stomatal conductance and transpiration
56. o is included to attach the 610 03 to the LI 610 if desired Do not attach the velcro to the battery compartment panel on the back of the 610 03 as repeated detachment can damage the panel Range Accuracy Operating Range Temperature Effect Pressure Connections Media Controls Housing Size Weight Power Requirement Battery Life Warranty Pressure Pressure Connection Ports High 0 to 1000 mbar 1 mbar resolution Low 0 to 199 9 mbar 0 1 mbar resolution 0 15 1 digit at 25 C 10 to 50 C 0 02 C 10 to 50 C Two ports for 1 8 ID 3 16 OD tubing Gases air Membrane switches for range selection and ON OFF Zero point correction control High impact resistant blue ABS molding 125 x 70x 31 mm 4 9 x 2 75 x 1 2 250 g 0 55 Ib including battery One 9V Eveready Alkaline 522 or equivalent 100 hours continuous use One year parts and labor Operation 3 17 Section 3 Connecting the LI 610 and 610 03 to the LI 6200 RS 232C Port The LI 610 and 610 03 analog outputs can be connected to appropriate pins on the LI 6200 RS 232C port if you wish to automatically incorporate dew point and pressure corrections into LI 6200 gas exchange calculations Only 8 of the 25 pins on the LI 6200 RS 232C port are actually used for serial communications Twelve of the remaining pins are used for 6 spare analog input channels and their associated grounds one pin is f
57. ock assemblies are drained water droplets can adhere to the brass hose barbs on the cooling blocks these droplets generally can t be forced out even under pressure from the LI 610 s air pump Because of this we recommend that if the LI 610 is to be stored and won t be exposed to freezing temperatures it is best to leave the system full of water If precipitates have formed at the bottom of the condenser block it is possible to thread a thin piece of wire down through the fill drain port and try to dislodge the deposits If the blockage is near the Peltier coolers use the syringe included with the LI 610 to try to dislodge the blockage as described above at Instrument Can t Achieve Setpoint Below Ambient Temperature Try a different battery or if using AC power check the AC voltage select switch on the AC Module to make sure that it is set properly Check the fuses to see if one has blown 6 2 Troubleshooting Reduced Air Flow Rate LI 610 Output Spits During Operation Water Pump and or Fan Do Not Run If the voltage select switch is set improperly the instrument may turn on even though the voltage is too low to activate the LO BATT circuit The instrument pumps will also operate but at a greatly reduced rate If the output air flow rate diminishes over time check the internal air filter and replace if necessary Reduced air flow rate may also be an indication that the bubbler stone in the condenser block is cor
58. or pressure kPa moist moist moist pure pure From Wexler s data using air air air water water Wexler Buck Buck Lowe LI COR Buck Buck LI COR Eq 3 4 Eq 3 10 Eq 3 11 Eq 3 12 Eq 3 4 Eq 3 10 Eq 3 12 0 019 0 019 0 019 0 019 0 051 0 051 0 051 0 051 0 125 0 126 0 126 0 125 0 286 0 288 0 288 0 286 0 611 0 614 0 614 0 611 1 227 1 233 1 233 1 227 2 337 2 347 2 347 2 337 4 243 4 260 4 262 4 243 7 378 7 414 7 412 7 377 12 340 12 419 12 399 12 339 17 502T Buck 1981 e T 0 61365 24097 kPa 8129 7 JT 221 3 Buck 1981 e T 0 61121 1 000724 3 2x10 P 5 9x10 PT e 7425787 Lowe 1977 e T a0 T al T a2 T a3 T a4 T a5 a6T a0 0 61078 al 0 044365 a2 1 4289 x 103 2 6506 x 10 5 a4 3 0312 x 107 a5 2 0341 x 109 6 1368 102 7 64487 LI COR 1990 e T 0 61083 x 102426247 Operation 3 15 Section 3 Using the 610 03 Digital Pressure Meter The 610 03 Digital Pressure Meter is a lightweight portable pressure gauge which can be used to measure differential pressure or vacuum from a variety of sources including the LI 610 Portable Dew Point Generator Follow these steps to measure over pressure in the LI 610 condenser block 1 2 3 4 5 6 Press the green button to turn the 610 03 ON A low battery is indicated by a BAT message in the lower left hand corner of the display Slight fluctuations may occur on the display if the two por
59. ors is a principal use of the LI 610 Relative Humidity is defined as RH x 100 a e T where e is the prevailing vapor pressure of a parcel of moist air at temperature T and e T is the saturation vapor pressure at the same pressure Relative humidity is the ratio of the actual vapor pressure to the maximum vapor pressure that can exist at equilibrium at a given temperature It is often necessary to establish a known relative humidity at a known temperature in some device For example one may want to calibrate a relative humidity sensor or establish a known RH in an airstream entering a leaf photosynthesis chamber This can be done using equations 3 4 3 6 and 3 7 or done approximately using the psychrometric chart given in Figure 3 2 3 10 Operation Section 3 Sample Calculations Example 1 Assume you wish to calibrate a relative humidity sensor in a leaf chamber where the air temperature is 23 0 C The LI 610 dew point temperature is to be set so that the chamber relative humidity will be 40 We shall neglect flow dependent pressure changes for the moment The steps to solution are 1 compute the saturation vapor pressure at 23 0 C using equation 3 4 2 solve equation 3 7 for the required chamber vapor pressure and 3 solve equation 3 4 for the required dew point temperature setpoint for the LI 610 1 The saturation vapor pressure at 23 C is 17 502x23 e 23 0 61365e 4097925 2 820 kPa
60. ous flow of water between the coolers and the radiator allows A precision platinum Resistance Temperature Detector RTD is used to monitor the temperature of the condenser block the condenser temperature is limited to 50 C excess heat to be dissipated 3 2 Operation Section 3 Operation If the temperature on the hot side of a Peltier cooler exceeds 65 C the coolers will automatically shut down to prevent overheating The coolers will subsequently turn back on when the temperature drops below this threshold After filling the LI 610 with distilled water Section 2 the instrument is ready to begin generating a water vapor stream 1 Turn the POWER switch ON The display shows the temperature setpoint TEMPERATURE SET the actual condenser block temp erature TEMP C or the battery voltage BATTERY depending upon the position of the function switch adjacent to the display 2 Set the function switch to the TEMP SET position Use the COARSE and FINE TEMP SET knobs to set the desired dew point temperature of the output air stream The COARSE adjustment knob changes the temperature set by large increments and allows you to get close to the desired set point very quickly The FINE temperature adjustment knob is then used to set the dew point precisely 3 Set the function switch to the TEMP C position and turn the COOLER switch ON The Peltier coolers liquid pump and radiator fan will turn on
61. ow the ambient temperature Click the H20 tab and note the present value of Sw Enter the span gas dew point temperature in the target entry Observe the H2O dew point and wait for it to stabilize This may take up to 15 or 20 minutes When the reading has stabilized click Span Note the value of S typically 0 9 1 1 Calibration 4 15 Section 4 Calibrating the LI 840 CO H O Infrared Gas Analyzer Run the 840 500 Windows software program and select Calibration from the View menu The Calibration window is the area in which you set the zero and span of the LI 840 Calibration It is recommended that you perform the zero calibrations first followed by the span calibrations To zero flow dry CO free gas through the LI 840 and make sure the optical cell is completely purged Press the Zero CO button The display will show ZERO and the text in the Calibration window is greyed out The zero will be set electronically and the current date will be entered in the Last zeroed on field when completed Repeat for the H20 channel To span connect a span gas of known concentration to the input air stream Make sure the cell is purged enter the value of the span gas and click on Span CO 4 16 Calibration Section 4 The display will show SPAN and the text in the Calibration window is greyed out The span will be set electronically and the current date will be entered in the Last spanned on f
62. piece of tubing with relatively large bore diameter 1 8 inch 3 2 mm or larger and the flow rate should be kept low when the measurement is actually made 0 25 liters per minute or less A small condenser over pressure may still develop but the condenser fill tube can be used to measure water column height with sufficient accuracy to estimate the condenser pressure One centimeter of water is equivalent to 0 097 kPa or about 0 1 kPa at ordinary temperatures See Section 4 for further information about calibration protocols Operation 3 9 Section 3 Temperature Effects Relative Humidity It is not necessary to correct vapor pressure for temperature differences that may occur between the LI 610 and the measuring instrument Small pressure differences may develop at points along the flow path due to flow rate dependent pressure drops but pressure is constant at a given point Equation 3 1 can be rearranged to give P pRT where p n V mole density mol m3 If total pressure and composition are constant then the partial pressures of individual components including water vapor are also constant It follows that an increase in temperature will cause a reduction in total gas density and the densities of individual components but no change in total pressure or vapor pressure Therefore no vapor pressure corrections are necessary for temperature differences that might occur in the system Calibration of relative humidity sens
63. point to 0 05 2 Remove the LI 1600 console from the case as described in Section 5 of the LI 1600 instruction manual For your safety do not operate the LI 1600 from AC power while performing this procedure 4 20 Calibration Section 4 Calibration Setting the Zero 1 Locate the zero and span potentiometers on the bottom console circuit board See the LI 1600 instruction manual p 5 10 Rev 6 for the location of these potentiometers Remove the silica gel from the sensor head silica gel desiccant pack Leave the cap from the desiccant pack off to minimize back pressure Connect a 3 7 5 cm length of 1 16 1 59 mm ID teflon tubing to the small hose barb on the cuvette exit port The tip of this barb is recessed and can be seen through the hole in the front of the LI 1600 sensor head shroud The LI 610 will be connected to the sensor head by inserting the teflon tube into the 1 8 3 17 mm ID Bev a line tubing connected to the LI 610 Turn the LI 1600 ON but do not press the HUM SET button Replace the chamber aperture cap with the solid calibration cap included with the 610 02 RH Calibration Accessories kit Alternatively a sheet of non porous non water absorbing material can be clamped over the aperture Closed cell polyethylene foam is a good material to use for this procedure in the absence of the 610 02 Set the LI 610 flow rate to about 0 2 to 0 3 liters per minute This low flow rate is ne
64. ponse Time Temperature Sensor Display Display Resolution Noise Level Flow Rate Flow Meter Type Flow Meter Accuracy Flow Outputs Maximum Input Flow Rate Maximum Pressure Differential between input amp output ports Maximum Pressure Surge Analog Output Command Input Low Battery Detection Operating Range Storage Conditions Power Requirements Weight Size 0 to 50 C limited to 35 C below the cooling water temperature 0 2 C 0 to 50 C lt 0 02 C per day at 25 C typical lt 0 04 C per day at 25 C maximum 0 01 C Typically 15 seconds per C when changing from ambient to a higher dew point 30 seconds per C for dew points below ambient Platinum resistance temperature detector RTD 4 1 2 digit LCD for displaying Temp Set Temp C or Battery voltage 0 01 C 0 01 C peak to peak Adjustable to 1 7 liters per minute maximum internal pump capability gt 1 5 liters per minute Dwyer series RMA 2 5 liters full scale 4 of full scale reading Two rapid connect hose fittings for 1 8 ID by 1 4 OD plastic tubing adjustable at Output 2 2 liters min 140 kPa 20 psi 35 kPa 5 psi 0 to 5 Volts 1000 output impedance 100 mV C 0 to 5 Volts 100 mV C LED display at 10 4 Volts automatic shutdown at 10V 0 to 50 C 0 to 95 RH non condensing 0 to 55 C 20 to 55 C when drained 10 5 to 16 VDC
65. rame chassis ground and four are not defined Channels 1 2 and 3 share a common ground as do channels 4 5 and 6 Appendix A 4 in the LI 6200 Technical Reference Manual gives the RS 232C pin assignments for Spare Channels 1 Determine which LI 6200 Spare Channels are to be used Assume that channels 1 2 and 3 are chosen but similar instructions would apply to channels 4 5 and 6 Assume that channel 1 pins 9 and 10 receives the LI 610 signal and channel 2 pins 11 and 12 receives the 610 03 signal Build a male 25 pin RS 232C connector with the configuration shown in Figure 3 3 Connect the LI 610 red lead to pin 9 and the black lead to pin 10 connect the 610 03 red lead to pin 11 and the black lead to pin 12 Use a jumper to connect the ground from channel 3 pin 15 to chassis ground pin 1 to ensure that the LI 6200 LI 610 and 610 03 all share a common ground The LI 6200 E2 Sensor List and E3 System Program must now be modified to read and interpret the LI 610 and 610 03 analog signals We shall compute the vapor pressure entering a leaf chamber EIN mb applying the pressure correction given by equation 3 6 The LI 610 input voltage is 100 mV C and the 610 03 input voltage is 1mV mb According to the LI 6200 Technical Reference Manual p 7 70 Spare Channel corresponds to software channel 08 and Spare Channel 2 corresponds to software channel 09 These two software channels in the E2 Sensor List must be turne
66. re Parts Kit Squeeze Bottle Syringe Algicide 610 04 BNC millivolt Leads 610 01 AC Module Unpacking amp Initial Inspection Check the packing list included with your LI 610 to verify that you have received everything that was ordered and that you have also received the following items This bag contains replacement parts for your LI 610 As you become familiar with the Dew Point Generator you will learn which items to keep close at hand and which items can be stored away A 250 ml plastic squeeze bottle is included to aid in filling the radiator assembly A plastic syringe is included to facilitate filling and draining of the condenser block in the LI 610 Refer to Sections 2 and 5 respectively for complete filling and draining instructions A small bottle of liquid algicide is included to prevent the formation of algae in the radiator assembly of the LI 610 Refer to Section 2 for complete instructions One set of millivolt leads terminated with a BNC connector is included for connection to either the Analog Output or Command Input fitings on the LI 610 front panel See Section 3 for a complete description of the function of these connectors 108 126 216 252 V AC 48 66 Hz for AC operation Unpacking and Initial Inspection 11 Section 1 Optional Accessories Several optional accessories are available for use with the LI 610 including 610 02 Relative Humidity Calibration Accessories for calibr
67. reference ports B 4 2 Section 4 View water channels Press F3 or F4 to make the water IRGAs the active ones Wait for equilibrium Watch the rates of change slopes If you are using Option A connected to sample Match On then be prepared to wait about 20 minutes until the rise in sample and reference concentration is negligible If you are plumbed for Option B sample and reference connected ignore the sample and only wait for the reference to equilibrate 3 to 5 minutes should be adequate Adjust the reference gain as needed When Td_R_ C is highlighted press T and J to adjust the H20 reference IRGA s span factor until Td reads correctly Figure 4 6 Adjusting 20 R use AJ CO2Suml CO2Suml Td S C 318 6 319 8 18 75 19 90 Mean 2 4E 0 4 5E 0 4 8E 2 3 1E 2 Slope Fan Fst 1 009 1 007 997 981 Mch ON CO2 S Figure 4 6 Adjusting the H5O span Adjust until the displayed dewpoint value 18 75 in the example above matches the LI 610 set point Select the sample IRGA Press or f4 to highlight S If you are plumbed for Option B continue with Step 8 If you re plumbed for Option A press T and J to adjust Td 5 until it reads correctly You are done Match mode ON Press M to make the Mch indicator read ON Calibration 4 3 Section 4 9 Note the reference dew point value Watch the left hand reference Td_C value It will likely drop a bit as the stil
68. res from 0 C to 50 C A more accurate formulation is given in equation 3 5 and Table 3 1 although it is evident from Table 3 1 that this is hardly necessary in practical calculations Therefore we shall consider e T P e T for pressures above 80 kPa The recommended equation for routine calculations of moist air saturation vapor pressure e T at a given temperature C and total pressure above 80 kPa is 17 502T e T 0 61121 1 004 24097 or 3 4 17 502T e T 0 61365 24097 kPa The dew point is the temperature at which moist air will be saturated with water vapor if it is cooled at constant pressure and mole fraction The LI 610 generates an air stream that is saturated at the temperature of the condenser block hence the name Dew Point Generator Operation 3 7 Section 3 Pressure Effects When the air stream leaves the LI 610 it will be subject to changes in temperature and total pressure The LI 610 pump lies upstream from the condenser and flow resistance due to the LI 610 plumbing and downstream equipment causes a small over pressure to develop in the condenser usually in the range of 0 6 kPa At atmospheric pressures above 80 kPa the saturation vapor pressure in the condenser is virtually independent of these small variations in total pressure and in any case they are taken into account by the enhancement factor The extent of this pressure dependence can be illustrated with t
69. roded or clogged with precipitates Clean the condenser block as described in Section 5 A severe loss of air flow may indicate that the air pump diaphragm has failed See Section 5 for instructions on replacing the pump diaphragm A pump that is functioning normally will generally output a pressure of 450 to 600 mb when measured at the TO CONDENSER port with the 610 03 Digital Pressure Meter If the air flow rate from the LI 610 is erratic or if water droplets appear in the FROM CONDENSER tube during operation i e the condenser spits it may be due to precipitates forming in the condenser block water Replace with distilled water and resume operation NOTE Operation of the LI 610 in environments with high CO concentrations gt 500 ppm may accelerate precipitate formation with attendant problems Change condenser water more often under those circumstances It may be necessary to change water daily in extreme cases CO concentrations gt 1000 ppm See Section 2 for complete details It is important that the output air stream is free of water drops as the dew point will be incorrect if this phenomenon occurs Check the FROM CONDENSER tube to see if water drops are present If the water pump and or air fan do not operate it may indicate that cooler switch has failed Contact LI COR for service information Troubleshooting 6 3 Appendix A Specifications Dew Point Range Accuracy Stability Repeatability Res
70. rve the concentration and wait for it to stabilize typically 1 minute Also note the present value of Figure 4 5 Zero C02 C2 last zeroed Dec 2 1999 at 3 10 16 PM Current Value Note this value Zero 10 Figure 4 5 Note value of Zco shown as Current Value When the reading has stabilized click Zero to set the CO zero After a brief delay the displayed CO value should be fluctuating around zero Check the resultant value of Zeo shown on the Zero CO page Figure 4 5 It should be near 1 typically between 0 85 and 1 1 This value will steadily increase as the internal chemicals lose effectiveness Now is a good time to check or set H20 zero if you have been flowing dry CO free air through the optical path Click the H20 tab and note the present value of Zwo Wait for the H5O reading to stabilize 3 or 4 minutes Click Zero Note the new value of Zwo typically between 0 65 and 0 85 Flow a CO span gas through the calibration tube at 0 5 to 1 liter minute 4 14 Calibration Section 4 Span H20 11 12 13 14 15 16 Click on the Cal tab Enter the mole fraction in the target entry When stable 1 2 minutes click Span Check the value of S typically 0 9 1 1 To set the H5O span flow air of known dew point through the calibration tube at about 0 5 to 1 0 LPM To avoid condensation use a dew point temperature several degrees bel
71. sconnect either the From Cooler or Troubleshooting 6 1 Section 6 Precipitates Have Formed and are Blocking the Water Lines Power On Problems To Cooler hoses from the back of the LI 610 Use the syringe supplied with the LI 610 and seal it to the hose fitting as best you can Then use the syringe to push and pull water through the system until the water flows freely This should dislodge any blockage that might inhibit coolant circulation If a blockage is detected flush it out of the lines The precipitates that cause these blockages are generally formed during storage by a reaction between water air and the brass hose fittings These precipitates can be prevented by keeping the radiator reservoir full of deionized water during storage if stored in temperatures above freezing If the above measures do not solve the problem the Peltier coolers may not be powered properly and you should contact LI COR As mentioned above precipitates can form within the LI 610 by a reaction between water air and the brass hose fittings used to connect the water hoses to the Peltier coolers and the condenser block If the cooler tubes are blocked the condenser block can overheat in a very short time causing the coolers to shut down In most cases these precipitates form when the LI 610 is stored without water in the radiator and condenser block assemblies as when it is stored in freezing conditions When the radiator and condenser bl
72. serve power The LI 610 should be turned OFF to prevent further battery discharge Connect a fresh battery and if you haven t already done so turn the LI 610 OFF and back ON to reset the shutdown circuit The LOW BATT light will shut off and normal operation will resume If AC line voltage is being used with the 610 01 AC Module make sure the AC VOLTAGE selector on the AC module is set correctly choose the 115 setting for 108 126V AC or the 220 setting for 216 252 V AC and plug the line cord into the AC receptacle To prevent personal injury never operate the LI 610 AC module if it is not installed in the Dew Point Generator Turn the POWER switch on the front panel ON The display will show the temperature setpoint TEMP SET the actual temperature TEMP of the condenser or the battery voltage BATTERY Pre Operation 2 5 Section 2 depending upon the position of the function switch on the right side of the display Turn the COOLER switch ON The liquid pump will start circulating water through the Peltier coolers and the radiator assembly When the AIR PUMP is switched ON and the FLOW ADJUST VALVE is opened the LI 610 will begin to generate an airstream with a dew point temperature equal to the condenser temperature established with the TEMP SET knobs Radiator Fill Cap Temperature Set Knobs ON OFF Switch Flow Adjust Valve Display Analog Output Low Battery LED Temperature Rotameters Set Switch
73. supplied with air having dew point Tg established at pressure AP After 60 minutes adjust the sensor housing span potentiometer so that the display reads RH Be sure that the cuvette temperature T is used in equation 4 1 EXAMPLE If the cuvette temperature T is 24 C the dew point temperature Tg is 21 C and the change in condenser pressure between no flow and the actual flow is 3 cm of water at a barometric pressure of 100 kPa then equation 4 1 becomes _ 0 997e 4 RH 5 e 12853 x 100 83 1 Calibration 4 27 Section 4 Check Intermediate Values Conduct the following procedures without further adjustment to the span potentiometer 1 Find the dew point temperature that corresponds to about 50 RH at ambient temperature using the psychrometric graph supplied Set the LI 610 to the dew point temperature and allow 60 minutes to elapse after Tg is reached Calculate the exact cuvette RH using equation 4 1 and compare the result to the displayed RH They should agree to within 3 RH Reset the LI 610 to a dew point corresponding to about 20 RH Repeat steps 2 and 3 Recheck the zero and span if there is a deviation of greater than 3 RH If the intermediate RH deviations are too large when the zero and span are set correctly you may wish to make adjustments to the 141 6200 RH Calibration Table FCT 47 to correct for sensor non linearity see p 7 14 of the LI 6200 Technical Reference Manu
74. t Press DoCO2 After about 5 seconds the CO readings for A and B should match 1 Set reference to 0 Temporarily set the operating mode to 0 or dry air in the reference cell If reference is being measured externally you won t have to do this Doa 1 Point Match with 0 dry air This matches the cells at a low concentration Change reference to the high concentration If reference is being measured externally you won t have to do this Do a 1 Point Match at the high concentration This matches the cells at a high concentration The match should be reasonably good between the two Calibration 4 9 Section 4 Box 3 Box 4 Setting the Span Calibrate Cell A Make sure you have done a one or two point This procedure is necessary periodically while match first 1 in REM Reference Estimation Mode operations Flow reference gas through A and the span gas through B The concentrations must be different 1 Flow a known gas through cell A Any concentration including 0 is fine Set or H20 action to Make cell Pick Make cell A read for or B read H20 You ll be prompted for the cell B target You will be prompted for the value concentration Wait for stability then press DoCO2 Press DoCO2 or DoH20 or DoH2O After 5 or 6 seconds cell A should be After about 5 seconds the cell B reading reading the target val
75. t for this common mode drift match first with a near zero concentration then match again at the higher concentration and the IRGA should then be reasonably well matched between those two concentrations The Make cell B read adjusts the span parameter for the calibration polynomial and should only be used when the cell A concentration is known that is don t do this while in REM NOTE You can use any concentration in the B cell to do this even 0 just make sure that there is a significant difference between the cell A and B concentrations The type of user calibrations that are appropriate depend on what operating mode you are using and there are basically three 1 Reference Cell A Is Known and Constant A constant known concentration is continually flowing through cell A The source may be scrubbed air or air from a tank or air from a dew point generator Il Reference Cell A Is Known but not Constant The cell A air stream is being measured by an external analyzer which is communicating the concentration to the LI 7000 through an auxiliary input The concentration changes with time but it is always being measured Il Reference Cell A is Estimated This is Reference Estimation Mode REM The LI 7000 is continually providing its best estimate of the cell A concentration The cell B concentration will have the same error as the cell A concentration so the 4 6 Calibration Section 4 1 Re
76. that for an ideal gas mixture X pj P Specifically let w be the mole fraction for water vapor mmol mol then Operation 3 5 Section 3 Pure Water Vapor gt 1000 3 3 The amount of water that can remain in the gaseous state at equilibrium is limited When pure water vapor is in stable equilibrium with a plane surface of pure water or ice with constant temperature and pressure at the interface it is said to be saturated The partial pressure of pure water vapor at saturation is a function of temperature alone and is called the saturation vapor pressure Tabulated values of the saturation vapor pressure of pure water vapor as a function of temperature based upon the formulation of Goff and Gratch 1946 are given in the Smithsonian Meteorological Tables List 1984 Equations relating saturation vapor pressure to temperature based upon those data are given by Lowe 1976 and LI COR 1990 Lowe s equation is a 6th order polynomial that gives accurate results Table 3 1 equation 3 11 and can be rapidly calculated on a digital computer However it has the major disadvantage that it is easily applied in only one direction i e to compute vapor pressure from temperature Given a vapor pressure it is difficult to solve Lowe s equation for temperature Lowe s equation is used in the LI 6252 CO Analyzer to compute vapor pressure from a dew point provided by an external dew point hygrometer Equation 5 12 11 6262
77. the TO COOLER fitting to absorb the small amount of water which will run out of the tubing Maintenance 5 3 Section 5 External Fan Filter Remove the hose wipe the contaminants off the screen and reassemble The external fan filter should be cleaned rinsed out or replaced as needed The filter is located behind the black filter cover on the instrument side panel pull the cover straight off to expose the filter Cleaning the Condenser Block The condenser block and or bubbler stone may become contaminated with mineral or other deposits resulting in a loss of air flow through the LI 610 A severe loss of air flow may also indicate that the air pump diaphragm has failed A pump that is functioning normally will generally output a pressure of 450 to 600 mb when measured at the TO CONDENSER port with the 610 03 Digital Pressure Meter If the pump appears to be functioning normally you may need to clean the condenser block with a solution of 1N acetic acid To clean the condenser block Drain the condenser block assembly it is not necessary to drain the radiator assembly Connect a new section of Bev a line tubing with attached female Luer lock to the fill drain fitting on the condenser block housing Turn the air pump on and open the flow adjust valve very slightly just enough to prevent any acetic acid from backing up into the hose attached to the bottom of the condenser block the condenser with IN
78. to 5 C below the ambient room temperature This will prevent local temperature fluctuations in the gas exchange system from causing condensation If required see Section 3 Pressure Effects connect the 610 03 Digital Pressure Meter to the condenser water fill port using the tubing provided Set the LI 610 flow rate to about 1 liter mint and allow moist air to pass through the analyzer for about 20 minutes Reduce the flow rate to about 0 25 liters for an additional 20 minutes or until the signal is adequately stable Read the pressure differential between the condenser and atmosphere Compute the condenser vapor pressure using equation 3 4 and then correct it for condenser over pressure using equation 3 6 Set the LI 6262 span to read the vapor pressure computed from equation 3 6 4 18 Calibration Section 4 Differential Mode H20 Zero Calibration Precautions You may now wish to check an intermediate vapor pressure You will find that the system will equilibrate more quickly with smaller water vapor changes No further span adjustments will be necessary for either absolute or differential operation However if you wish to operate in differential mode it will be necessary to reset the zero each time a new reference gas is passed through the LI 6262 reference cell It is only necessary to set zero in differential mode The analyzer gain is set with a span adjustment in Absolute Mode No further span adjustmen
79. ts on the top of the 610 03 are open Select the range of the instrument by pressing either the 1 or 0 1 buttons Pressing the 1 button selects a range of 0 1000 mbars 1 mbar resolution and the 0 1 button selects a range of 0 to 199 9 mbars 0 1 mbar resolution To use the 610 03 with the LI 610 you would ordinarily select the 0 1 button Attach a male Luer lock in the LI 610 spares kit to the fill drain port on the LI 610 condenser housing Connect a section of the 1 8 ID tubing included between the Luer lock and the left hand pressure connection port on the top of the 610 03 The display will show positive values if pressure is exerted on the left port or if a vacuum is applied to the right port The display will show negative values if a vacuum is applied to the left port or pressure is exerted on the right port With the LI 610 turned OFF zero the 610 03 by turning the knob on the bottom of the pressure meter in either direction until the display reads 000 or 00 0 The millivolt output connector is located between the two pressure ports on the top of the 610 03 The voltage output from the 610 03 is linear and corresponds to 1 millibar 1 millivolt Connect the red lead to the positive terminal of your measurement device and the black lead to the ground or chassis ground if available Press the red button to turn the 610 03 off 3 16 Operation Section 3 610 03 Specifications NOTE Velcr
80. ts are necessary for operation in Differential Mode because the calculations automatically correct for analyzer sensitivity changes due to different reference cell humidities 1 Set zero and span in Absolute Mode as described above 2 Flow a reference gas through both the reference cell and sample cell for 20 min at about 1 liter min Reduce the flow to 0 25 liters min for an additional 20 minutes or until the displayed water vapor differential is sufficiently stable 3 Enter the reference cell water vapor mole fraction WREF in units of mmol mol WREF is computed from the dew point temperature T as e T P AP WREF 1000 4 Adjust the displayed water vapor differential channels 33 35 or 37 to read zero Pressure influences CO and water vapor infrared absorptance by altering gas density and by changing the absorption per mole of gas Therefore careful attention must be paid to pressures in the analyzer The barometric pressure should be accurately measured and entered into the instrument All LI COR CO and H O analyzers are calibrated in terms of mole fraction because this has been found to give the best results as theory predicts Calibration 4 19 Section 4 Span adjustments can be used to correct the CO or mole fractions if pressure is entered incorrectly or if a nominal value is used however subsequent conversions to partial pressure will be incorrect if they are computed from an incorrect b
81. u determine in advance the accuracy that is required and then establish the equilibration time necessary to meet your requirements The equilibration times given in these protocols are meant only as starting points Calibration 4 17 Section 4 Absolute Mode H20 Zero Calibration Absolute Mode H20 Span Calibration The protocols for setting zero and span in Absolute Mode and Differential Mode are quite similar 1 Turn on the LI 6262 Change the chopper desiccant and soda lime if necessary Pass dry air from a compressed air source or from anhydrous magnesium perchlorate into the analyzer sample and reference cells You may find that air from a tank of compressed gas contains a very small amount of water vapor especially if tank pressure is low Use anhydrous magnesium perchlorate after the tank if necessary If the LI 6262 is not equipped with a pressure transducer check at FCT 43 enter the current barometric pressure into Function 77 and also enter WREF 0 Function 02 or 68 The analyzer and flow path will dry down faster at higher flow rates We suggest you use 1 liter dry air for 20 to 30 minutes through both sample and reference cells then reduce the flow rate in both cells to 0 25 liters min for 10 to 20 minutes prior to setting zero Set zero Set the LI 610 to a dew point corresponding to about 80 RH at ambient temperature This typically means that the dew point temperature should be set 3
82. ue should be on target User Calibration Example Example 1 Reference Estimation Mode REM for both CO and H20 REM is used when precise differential concentrations are required and where absolute accuracies are less important In this example a tank of gas of 370 umol mol CO in dry air is used for the CO calibration The LI 610 is used to provide an airstream with known dew point to Cell A for the H5O calibration A periodic user calibration procedure for operating the LI 7000 in REM is given below 1 Flow the calibration gas through both cells of the LI 7000 optical bench 2 Press Shift 1 to display the calibration group labels 3 Press the SetRef key f1 The Reference Cell Options are displayed Press Edit f1 to edit the options Choose Estimated Press OK Repeat for H5O and edit the H5O units box to display the desired units C 4 10 Calibration Section 4 10 11 12 11 12 Press the Calib key f4 In the H2O Actions box highlight cell A read and press OK Highlight Exact value and press OK f5 Enter the dew point of the airstream provided by the LI 610 and press OK f5 Press the DoH20 key f3 and wait for about 5 seconds Cell A will now read the H20 value entered above Press the Calib key 4 In the H5O Actions box highlight cell B match cell A and press OK Press the DoH20 key f3 and wait for about 5 seconds The cell
83. uer lock into the 30 ml syringe Use the syringe to draw the water out of the condenser block The block holds approximately 20 25 ml of water when full Alternatively the condenser block can be drained by plugging the two output ports on the instrument front panel Attach the section of Bev a line tubing to the fill drain fitting as described above Close the flow adjust valve completely Turn the power switch and the air pump ON and open the flow adjust valve slightly to force the water out through the fill drain tube Leave the air pump on until all of the water has drained out of the condenser block Maintenance 5 1 Section 5 Radiator Assembly Follow these steps to drain the radiator cooler assembly it is not necessary to remove the LI 610 cover to drain the radiator e Disconnect the tubing attached to the FROM COOLER and TO CONDENSER fittings e Attach a short piece of tubing between these same two fittings e Turn the air pump ON and open the flow adjust valve This will force air through the radiator assembly causing the water to flow out of the tube which was previously attached to the FROM COOLER fitting e Leave the air pump ON until all of the water has been purged from the system Internal Air Filter The frequency with which the Balston air filter needs to be replaced will depend upon the operating environment it will generally need replacement after 6 months to 1 year The filter is located inside the

LI-610 Manual - LI-COR

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