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LI-COR LI-610 Operating And Service Manual

Portable dew point generator
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LI-610
Portable Dew Point Generator
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Summary of Contents for LI-COR LI-610

  • Page 1 LI-610 Portable Dew Point Generator Instruction Manual ®...
  • Page 2 LI-610 Portable Dew Point Generator Operating and Service Manual...
  • Page 3 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.

  • Page 4: Table Of Contents

    Filling the Radiator .......................... Filling the Condenser Block ......................Power On ..............................Section III. OPERATION General Description ..........................Air Flow Through the LI-610 ......................Water Flow In the LI-610 ........................ Operation ..............................Command Input ............................Analog Output ............................Theory of Operation..........................
  • Page 5 Water Sorption ..........................3-13 Maximum Flow Rates ........................3-13 Using the 610-03 Digital Pressure Meter ....................3-16 Connecting the LI-610 and 610-03 to the LI-6200 RS-232C Port............3-18 References ............................... 3-20 Section IV. CALIBRATING LI-COR INSTRUMENTS General Information ..........................Calibrating the LI-6400 H O Analyzer....................
  • Page 6 Calibrating Relative Humidity Sensors (General) .................. 4-29 Calibrating Dew Point Hygrometers (General) ..................4-29 References............................... 4-29 Section V. MAINTENANCE Draining the LI-610 ..........................Condenser Block..........................Radiator Assembly .......................... Internal Air Filter ............................ Internal Water Filter Screen ........................External Fan Filter ..........................Cleaning the Condenser Block........................

  • Page 7: Section I. Unpacking And Initial Inspection

    Section I. Unpacking & Initial Inspection What's What 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...

  • Page 8: Optional Accessories

    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.

  • Page 9: Section Ii. Pre-Operation

    To fill the radiator assembly, remove the black radiator fill cap on the top Filling the Radiator of the LI-610 instrument case (Figure 2-1). The cap is not threaded, and can be pulled straight up. •...
  • Page 10 “antifreeze”). A 50/50 mixture of ethylene glycol/water will protect the radiator from freezing to approximately -40 °C. Ethylene glycol is the recommended antifreeze; do not use propylene glycol or other antifreeze mixtures. Radiator Fill Figure 2-1. LI-610 top view, showing location of radiator fill cap. Pre-Operation...

  • Page 11: Filling The Condenser Block

    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.

  • Page 12: Power On

    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.
  • Page 13 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...
  • Page 14 Peltier coolers and the radiator assembly. When is switched ON and the AIR PUMP FLOW ADJUST VALVE opened, the LI-610 will begin to generate an airstream with a dew point temperature equal to the condenser temperature established with the knobs.

  • Page 15: Section Iii. Operation

    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...

  • Page 16: Water Flow In The Li-610

    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 Water Flow In of dissipating the heat generated by the two Peltier coolers attached to the LI-610 the condenser block (Figure 3-1).

  • Page 17: Operation

    OUTPUT 2 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.

  • Page 18: Command Input

    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.

  • Page 19: Theory Of Operation

    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 When a gas stream passes through the LI-610 condenser, water vapor is Ideal Gas Laws added or removed so that the exiting gas stream is saturated at the condenser temperature.

  • Page 20: Pure Water Vapor

    Equation 5-12 (LI-6262 CO O Analyzer Instruction Manual) of LI-COR (1990) can be converted to the form: saturation vapor pressure at temperature T, e(T) = a × 10 [bT/(c+T)] .

  • Page 21: Moist Air

    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.

  • Page 22: Pressure Effects

    (1.5 liters min ) 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.
  • Page 23 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.

  • Page 24: Temperature Effects

    Therefore, no vapor pressure corrections are necessary for temperature differences that might occur in the system. Calibration of relative humidity sensors is a principal use of the LI-610. Relative Humidity Relative Humidity {%} is defined as ×...

  • Page 25: Sample Calculations

    Example 1. Assume you wish to calibrate a relative humidity sensor in a Sample Calculations 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%.
  • Page 26 3 before proceeding. 1. 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 + ∆...

  • Page 27: Additional Relationships

    P = barometric pressure, ∆P = condenser over-pressure, = LI-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 T with over- pressure ∆P.
  • Page 28 Section 3 Relative Humidity (%) 12.365 100% Saturation Vapor Vapor • • Pressure Pressure at T & at T 40% RH • • Dewpoint Air Temp. Temp., T Temperature (°C) Figure 3-2. Psychrometric Chart showing temperature, vapor pressure, and relative humidity. 3-14 Operation...
  • Page 29 From Wexler's data using Temp. water water water (°C) Buck Buck Buck LI-COR List Wexler Buck Lowe LI-COR Eq. 3-10 Eq. 3-4 Eq. 3-11 Eq. 3-12 Eq. 3-4 Eq. 3-10 Eq. 3-12 0.019 0.019 0.019...

  • Page 30: Using The 610-03 Digital Pressure Meter

    (0.1 mbar resolution). To use the 610-03 with the LI-610, you would ordinarily select the “0.l” button. 3) 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"...
  • Page 31 Section 3 NOTE: Velcro 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. Pressure Connection Ports...
  • Page 32 610-03 signal. 2. 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.
  • Page 33 The E3 System Program must be expanded to compute the incoming vapor pressure from LI-610 and 610-03 input voltages. 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.

  • Page 34: References

    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 1 and 2). References Buck, A.L. 1981. New equations for computing vapor pressure and enhancement factor.

  • Page 35: Section Iv. Calibrating Li-Cor Instruments

    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 LI-6262, LI-7000, LI-7500, and LI-840 CO O 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.
  • Page 36 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 reference ports (B).
  • Page 37 IRGA’s span factor until Td_R_°C reads correctly (Figure 4-6). Figure 4-6. Adjusting the H O 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 )to highlight Td_S_°C.

  • Page 38: Calibrating The Li-7000 Coo Infrared Gas Analyzer

    Section 4 Note the reference dew point value Watch the left hand (reference) Td_C value. It will likely drop a bit, as the still unequilibrated air from the sample cell enters the reference cell. When it stabilizes (30 seconds), set the sample IRGA to read that value.
  • Page 39 Section 4 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 H O. 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.

  • Page 40: Calibration Instructions

    Section 4 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.
  • Page 41 Section 4 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 I. Reference (Cell A) Is cell, there are two user calibrations that you may want to do.

  • Page 42: Calibrating For Rem Operations

    Section 4 If you are going to be operating with an unknown concentration of gas III. Calibrating for REM flowing though the A cell, there are two calibrations that you will need to Operations do periodically. Calibrate Cell A (initially, and periodically thereafter) The cell A calibration (Box 4, below) is critical to how REM works.
  • Page 43 Section 4 Box 1 Box 2 One Point Match Two Point Match This procedure will match the cells at a single The two point match will match the cells at a concentration. low and a high concentration. The low concentration should be <20 µmol/mol for (<3 mmol/mol for H O);...

  • Page 44: User Calibration Example

    370 µmol/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 H O calibration. A periodic user calibration procedure for operating the LI-7000 in REM is given below.
  • Page 45 A read...' Highlight and press (f5). Enter the dew point of 'Exact value' the airstream provided by the LI-610, and press (f5). Press the DoH2O key (f3) and wait for about 5 seconds. Cell A will now read the H O value entered above.

  • Page 46: Calibrating The Li-7500 Coo Infrared Gas Analyzer

    Section 4 Calibrating the LI-7500 CO O Infrared Gas Analyzer To avoid condensation problems choose a dew point temperature that is Preliminary 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.
  • Page 47 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;...

  • Page 48: Zero Co

    Section 4 Zero CO Observe the CO concentration and wait for it to stabilize (typically 1 minute). Also, note the present value of Z (Figure 4- Note this value Figure 4-5. Note value of Z , shown as Current Value. When the reading has stabilized, click to set the CO zero.

  • Page 49: Span H 2 O

    Section 4 Click on the CO Cal tab. Enter the mole fraction in the target entry. When stable (1-2 minutes) click . Check the value of S Span (typically 0.9-1.1). Span H To set the H O span, flow air of known dew point through the calibration tube at about 0.5 to 1.0 LPM.

  • Page 50: Calibrating The Li-840 Coo Infrared Gas Analyzer

    Section 4 Calibrating the LI-840 CO O Infrared Gas Analyzer Run the 840-500 Windows software program, and select from Calibration the View menu. The Calibration window is the area in which you set the zero and span of the LI-840. It is recommended that you perform the zero calibrations first, followed by the span calibrations.

  • Page 51: Preliminary

    The span will be set electronically, and the current date will be entered in the "Last spanned on" field when completed. Repeat for the O channel using the LI-610 to provide the airstream with known dew point. Calibrating the LI-6262 CO...

  • Page 52: Absolute Mode H 2 O Zero Calibration

    0.25 liters min for 10 to 20 minutes prior to setting zero. Set zero. 1. Set the LI-610 to a dew point corresponding to about 80% RH at Absolute Mode H ambient temperature. This typically means that the dew point Span Calibration temperature should be set 3 to 5 °C below the ambient room...

  • Page 53: Differential Mode H 2 O Zero Calibration

    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.
  • Page 54 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...

  • Page 55: Calibration: Setting The Zero

    Closed cell polyethylene foam is a good material to use for this procedure, in the absence of the 610-02. 1. Set the LI-610 flow rate to about 0.2 to 0.3 liters per minute. This Calibration: Setting...

  • Page 56: Calibration: Setting The Span

    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(ClO...

  • Page 57: Check Intermediate Values

    Find the dew point temperature that corresponds to about 50% RH at ambient temperature using the psychrometric charts in Appendix C. 2. Set the LI-610 to the dew point temperature and allow 60 minutes to elapse after T is reached.

  • Page 58: Precalibration

    1 through 4. Calibrating the LI-6200 or LI-6000 Portable Photosynthesis System Humidity Sensor 1. Set the LI-610 dew point to 0.05 °C. Precalibration 2. Mount the LI-6200 or LI-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.
  • Page 59 12” (300 mm) length of 1/8” (3.17 mm) 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...

  • Page 60: Calibration: Setting The Zero

    RH IN = 0 CORR RH = Y 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. Remove the remaining water vapor from the air by connecting a tube of fresh anhydrous Mg(ClO between the LI-610 and the sensor housing.

  • Page 61: Calibration: Setting The Span

    80% R.H. at T = 25 °C, set T = 21.3 °C. 4. 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 T , and the LI-610 dew point temperature T 5.

  • Page 62: Check Intermediate Values

    Values 1. Find the dew point temperature that corresponds to about 50% RH at ambient temperature using the psychrometric graph supplied. 2. Set the LI-610 to the dew point temperature and allow 60 minutes to elapse after T is reached.

  • Page 63: Calibrating Relative Humidity Sensors (General)

    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;...

  • Page 64: Section V. Maintenance

    Section V. Maintenance Draining the LI-610 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. Condenser Block To drain the condenser block: •...

  • Page 65: Radiator Assembly

    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. • Disconnect the tubing attached to the FROM COOLER fittings. CONDENSER • Attach a short piece of tubing between these same two fittings.

  • Page 66: Internal Water Filter Screen

    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 the...

  • Page 67: External Fan Filter

    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 port with the 610-03 Digital Pressure Meter.

  • Page 68: Fuses

    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.
  • Page 69 • 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. Maintenance...

  • Page 70: Recharging The 6200B Battery

    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.

  • Page 71: Section Vi. 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 Instrument Can't noise every few seconds, condensation in the radiator housing, and an Maintain Dew Point inability for the instrument to maintain the chosen dew point.
  • Page 72 "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.
  • Page 73 450 to 600 mb, when measured at the port with the TO CONDENSER 610-03 Digital Pressure Meter. If the air flow rate from the LI-610 is erratic, or if water droplets appear LI-610 Output "Spits" in the tube during operation (i.e., the condenser...
  • Page 74 Appendix A. Specifications Dew Point Range: 0 to 50 °C (limited to 35 °C below the cooling water temperature). Accuracy: ± 0.2 °C (0 to 50 °C). Stability: < 0.02 °C per day at 25 °C typical; < 0.04 °C per day at 25 °C maximum.
  • Page 75 Appendix B. Saturation Vapor Pressure Table Temp.°C 0.614 0.618 0.623 0.627 0.632 0.636 0.641 0.646 0.650 0.655 0.660 0.664 0.669 0.674 0.679 0.684 0.689 0.694 0.699 0.704 0.709 0.714 0.719 0.724 0.729 0.734 0.740 0.745 0.750 0.756 0.761 0.766 0.772 0.777 0.783 0.788...
  • Page 76 Appendix C. Psychrometric Charts Relative Humidity (%) 12.365 100% Saturation Vapor Vapor • • Pressure Pressure at T & at T 40% RH • • Dewpoint Air Temp. Temp., T Temperature (°C) Psychrometric Chart showing temperature, vapor pressure, and relative humidity (0 to 50 °C). Psychrometric Charts...
  • Page 77 Appendix C Relative Humidity (%) 5.62 Temperature (°C) Psychrometric Chart showing temperature, vapor pressure, and relative humidity (0 to 35 °C). Psychrometric Charts...
  • Page 78 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.
  • Page 79 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.
  • Page 80 LI-COR, inc.'s examination discloses to have been defective in material or workmanship without charge and only under the following conditions, which are: The defects are called to the attention of LI-COR, inc. in Lincoln, Nebraska, in writing within one year after the shipping date of the instrument.
  • Page 81 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 customer to make such repairs as covered by this limited warranty.
  • Page 82 ® LI-COR, inc. 4421 Superior Street P.O. Box 4425 Lincoln, Nebraska 68504 USA Phone: 402-467-3576 FAX: 402-467-2819 Toll-free 1-800-447-3576 (U.S. & Canada) envsales@licor.com www.licor.com...

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