LI-COR li-6262 Instruction Manual
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LI-COR li-6262 Instruction Manual

Co2/h2o analyzer
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LI-6262
CO
/H
O Analyzer
2
2
INSTRUCTION MANUAL
®

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Summary of Contents for LI-COR li-6262

  • Page 1 LI-6262 O Analyzer INSTRUCTION MANUAL ®...
  • Page 2 LI-6262 CO O Analyzer Operating and Service Manual O A N A L Y Z S P A N ZE R O ↑ EE X, ↓ S P A N ZE R O Publication Number 9003-59 March, 1996 Software Version 2.02 LI-COR, inc.
  • Page 3 3. Plug the instrument into a different outlet (if so equipped) so that the instrument and receiver are on different branch circuits. If necessary, the user should consult LI-COR or an experienced radio/television technician for additional suggestions. The Federal Communications Commission has prepared a booklet entitled "How to Identify and Resolve Radio-Television Interference Problems"...
  • Page 4 LI-COR MAKES NO WARRANTY OF ANY KIND WITH REGARD TO THIS MATERIAL, INCLUDING, BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF MERCHANT- ABILITY 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 5: Table Of Contents

    Table of Contents Section I. Unpacking and Inspection 1.1 What's What ..................1-1 1.2 Checking the Batteries ..............1-3 Section II. Setup and Operation 2.1 Setup and Operation ................. 2-1 2.2 Power On ................... 2-3 2.3 Gelman Filter Installation ..............2-4 2.4 Absolute vs.
  • Page 6 6.6 Using the 6262-03 Pressure Transducer ..........6-15 Section VII. Maintenance 7.1 Recharging the 6000B and 6200B Batteries ........7-1 7.2 Opening the LI-6262 ............... 7-1 7.3 Internal Soda Lime/Desiccant ............7-2 7.4 External Soda Lime/Desiccant ............7-4 7.5 Fan Filter ................... 7-6 7.6 Fuses ....................

  • Page 7: What's What

    1.1 What's What This procedure should be followed if you have just taken delivery on your LI-6262. Check the packing list to verify that you have received everything that was ordered and that you have also received the following items: Calibration Sheet - This data sheet contains a copy of the calibration information entered into the analyzer at the factory.
  • Page 8 The dew point temperature of the air stream can be viewed on the LI-610’s 4 1/2 digit LCD display, or output to the LI-6262 directly, as an analog Unpacking & Inspection...

  • Page 9: Checking The Batteries

    The LI-670 also can be used as a power source for the LI-6262; a built-in low battery detection circuit monitors battery life of the system. Mounting brackets are included for attaching the LI-670 and LI-6262, making the system completely portable.

  • Page 10: Setup And Operation

    Absolute vs Differential Mode Operation below. Turn the power ON. The LI-6262 can be operated with AC or DC power. See Section 2.2, Power On below. Calibrate the analyzer as described in Section 4.
  • Page 11 Connect sample airstream to be measured. Configure analyzer for data output. Data can be obtained from the LI-6262 in several different ways; from the display, via RS-232C output, or from one of the analog output channels. See Section 6, Interfacing, for more information.

  • Page 12: Power On

    . See Section 5, FCT 04. Begin making measurements. 2.2 Power On If a LI-COR rechargeable battery is being used, connect it to the 10.5-16VDC battery connector on the rear panel. The 6000B Rechargeable Battery will provide power for approximately 3.2 hours at 25 °C, or 2.4 hours at 40 °C.

  • Page 13: Gelman Filter Installation

    If you intend to operate the LI-6262 with battery power for more than 3 hours with the 6000B (6 hours with the 6200B), it is recommended that a user-supplied...

  • Page 14: Absolute Vs. Differential Mode Operation

    Section 2 Replace the filters when flow rates drop due to particle retention, or when the apparent LI-6262 response to changes in humidity becomes slow due to filter retention of hygroscopic material. When using the LI-6262 in high flow rate applications (e.g. eddy correlation) or where sample air is particularly dirty, you may consider stacking two filters in series.
  • Page 15 Section 2 Prepare a soda lime/desiccant tube, as described in Section 7.4, and attach to holder on the back panel. SCRUBBER Differential Mode Operation Orient the scrubber tube so that the soda lime is on the bottom and the magnesium perchlorate is on top. Attach the bottom hose (nearest the soda lime) to the FROM CHOPPER fitting.
  • Page 16 Section 2 To chopper Magnesium Perchlorate Fiberglass Wool Soda Lime From chopper Figure 2-2. Hose attachments to external soda lime/desiccant tube assembly. Absolute Mode Operation IMPORTANT: Air flow created by movement of the chopping shutter disc is sufficient to purge the reference cell of CO , but is not sufficient to remove all of the water vapor in the reference cell.
  • Page 17 Section 2 Mg(ClO SAMPLE REFERENCE CHOPPER FROM CHOPPER SAMPLE REFERENCE SODA LIME PUMP Figure 2-3. Hose connections for operation in absolute mode. Setup & Operation...

  • Page 18: Section Iii. Theory Of Operation

    Operation SP AN ZE RO 3.1 General Description The LI-6262 is a differential, non-dispersive, infrared (NDIR) gas analyzer. The CO and H O measurements are based on the difference in absorption of infrared (IR) radiation passing through two gas sampling cells. The...

  • Page 19: Calculating Gas Concentration - General

    50%. 3.2 Calculating Gas Concentration - General LI-COR gas analyzers use a lead selenide detector that operates approximately as a linear quantum counter; that is, over much of its range the detector signal output ν is proportional to the number of photons reaching the detector.
  • Page 20 Section 3 - ν V = k(ν The analyzer operates in such a way as to keep ν constant, so we can factor ν out of the quantity in parentheses, define K = kν , and obtain,   υ −...
  • Page 21 Section 3 The factory calibration of the analyzer consists of measuring the output V at several gas concentrations, and determining the coefficients for a fifth order polynomial (H O uses a third order polynomial) F(V) that relates V to gas concentration, with a zero gas concentration in the reference cell.
  • Page 22 Section 3 two cells are identical, then for a given gas concentration, the transmittance will be the same whether it is computed against zero between the cells or within either cell. Now, suppose the reference cell contains CO mole fraction C .

  • Page 23: Calculating Co 2 Concentration

    Section 3 In this section we have assumed that the sample and reference cells are optically identical. Strictly speaking, of course, that is not true. This can be illustrated by setting zero with zero gases in both the sample and reference cells and then placing a single span gas in both cells.
  • Page 24 7 6448   where z = log   .61083 and e is vapor pressure in kPa. The LI-6262 computes the water vapor weight fraction w (mg/g, FCT 36) 3-17 where M is given after equation 3-12. Theory of Operation...

  • Page 25: Pressure Broadening Due To Water Vapor

    Section 3 3.5 Pressure Broadening Due to Water Vapor Water vapor can influence infrared detection of CO in three ways: 1) direct absorption in the CO waveband of interest, 2) dilution, and 3) pressure broadening. Direct infrared absorption by water vapor can be virtually eliminated by judicious choice of wavebands and filters, and methods to correct for dilution are well known (Section 3.6);...
  • Page 26 1.5 against dry air. The value of a used in 3-20 is entered into the LI-6262 using FCT 78. Equation 3-20 can be extended to include nitrogen as standard, and both water vapor and oxygen (or other gases) as variable components. P...
  • Page 27 In principle, equation 3-26 can be solved for mole fraction, giving   −1 3-27   Since LI-COR gas analyzers produce an output voltage that is proportional to absorptance, V=KA 3-28 substituting 3-28 into 3-27 yields   ...

  • Page 28: Dilution Corrections

    3.6 Dilution Corrections A dilution correction can be applied in the LI-6262, if desired. When one component gas of multicomponent mixture is decreased at constant pressure, the partial pressures of all other components are increased accordingly. For...
  • Page 29 It is important to distinguish the different water corrections that can be applied in the LI-6262. The Vapor Flag (FCT 76) can be in one of three states: 0 - Corrections Off: No pressure broadening or dilution corrections are applied.
  • Page 30 Section 3 time the reference cell is scrubbed. The same is true when ambient air is returned to the reference cell. It is easier to leave the reference gas alone and scrub the sample cell; this avoids zero shifts and gain changes. One can then measure the output voltage V and compute V and C according to equations 3-34 and 3-35.
  • Page 31 Section 3 References Goff, J.A., and S. Gratch, 1946. Trans. Amer. Soc. Heat. and Vent. Eng., Vol. 52, p. 95. Jamieson, J.A., et.al. 1963. Infrared Physics and Engineering. McGraw-Hill, New York, N.Y. p. 65. List, R.J. 1966. Smithsonian Meteorological Tables, 6th rev. ed. The Smithsonian Institution, 527 pp.

  • Page 32: Section Iv. Calibration

    CO These coefficients should be quite stable over time, but we recommend that they be checked every two years by returning the LI-6262 to LI-COR for recalibration. The user calibration consists of adjusting the zero and span potentiometers so that the analyzer's output matches the linearization polynomial F(V).

  • Page 33: Differential Mode Calibration

    Section 4 4.2 Differential Mode Calibration It is important to remember that in differential mode the pressures on the two sides of the analyzer must be kept the same. For this reason, never connect the exit ports ( ) to anything - just vent SAMPLE OUT REFERENCE OUT them to the atmosphere, or to tubes of equal length.
  • Page 34 It is likely that zero and reference gases containing known amounts of water vapor will be produced by a dewpoint generator, such as the LI-610, or measured with a dewpoint hygrometer. However, the LI-6262 requires that the reference cell water vapor mole fraction be entered as a parameter before differential measurements can be performed.
  • Page 35 Section 4 The H O zero and span calibration is identical to that for CO ; however, allow adequate time for equilibration (several minutes after changing the humidity). Set the H O reference to zero (FCT 68). If you are not using the 6262-03 Pressure Transducer, enter the barometric pressure in FCT 77.

  • Page 36: Absolute Mode Calibration

    Steps 1 thru 5 above for differential mode calibration. 4.4 H O Absolute Mode Caution When using the LI-6262 to measure water vapor in absolute mode, note the following: When the LI-6262 is configured as described in Section 2.2 for absolute...
  • Page 37 Section 4 Figure 4-2 shows one way in which the LI-6262 may be set up with an external pump providing air flow through the reference cell circuit. The arrows indicate the direction of air flow through the analyzer. It is...
  • Page 38 Plug battery into the battery jack on the 6262-04, or connect a power cord to the LI-6262 if using AC power. Important Note: The 6262-04 Reference Pump must be turned off independently; it will not shut off when the LI-6262 is powered off.
  • Page 39 Section 4 Figure 4-3. 6262-04 Reference Pump installed on LI-6262 back panel. Calibration...

  • Page 40: Pressure Corrections

    This flow/concentration relationship is linear over the entire measurement range of the LI-6262. If another flow rate is used, a new correction will have to be calculated. 4.6 Setting the Zero and Span in Software...
  • Page 41 When sending a remote command, you have the option of entering the Zero and Span values, or allowing the analyzer software to calculate the values for you. The following examples demonstrate how you can calibrate your LI-6262 in software for both absolute and differential measurements. Remote Commands...
  • Page 42 (Span T /T)/V calc meas meas NOTE: The LI-6262 will not accept remote commands while the Test Menu is active. Exit the Test Menu and enter display mode; the remote command will then be executed. Absolute Mode Calibration Set the CO zero.

  • Page 43: Using The Li-670 Flow Control Unit

    Use tank pressure to provide flow at a nominal rate near that used during measurements. Final flow rate adjustments can be made with the LI-670 vents. SAMPLE REFERENCE . When the reading is steady, adjust the zero potentiometer on the LI-6262 until the display reads zero. 4-12 Calibration...
  • Page 44 Reference Scrub LI-670 Scrub only the reference cell. The LI-6262 is now ready for use in absolute mode. Differential mode operation requires three additional steps. Differential mode. Set zero. Perform steps 1 through 6, and then turn OFF the R E F E R E N C E switch.
  • Page 45 Diff. Scrub Ports Swap Zero Reference Scrub LI-670 Scrub the sample cell. The LI-6262 zero or span can be checked during measurements by turning ON the Diff Zero switch, and then using whichever scrubbers are needed. Ref. Sample Aux. Sample Scrub Diff.

  • Page 46: Section V. System Software

    ↓ Software SP AN ZE RO 5.1 Using the Keypad The LI-6262 uses a 16-key keypad for entering all software function commands and calibration data. The keys are arranged as in Figure 5-1, and function as follows: FUNCTION ↑ ↓...

  • Page 47: Software Overview

    Section 5 5.2 Software Overview All software commands are executed by pressing FUNCTION and then entering a two-digit function code. Some codes execute a function directly, while others access scrollable lists of options, or other functions, any one of which can be selected by pressing ENTER All functions are contained in the main menu, by order of function code.

  • Page 48: Console Commands

    FCT 00 Remote Commands Certain function codes can be sent to the LI-6262 from a computer or terminal, as shown on the console command card. Section 6.2 gives a complete explanation of how to connect your computer and LI-6262 for data transfer and for sending remote commands.
  • Page 49 01 CO Calibration Function 01 is actually a group of functions; executing FCT 01 performs functions 51-59 and 76. The LI-6262 is calibrated using a 5th order calibration polynomial of the form: µmol/mol = A(mV) + B(mV) + C(mV) + D(mV) + E(mV) .
  • Page 50 FCT 02-03 02 H O Calibration Function 02 performs functions 61-65, and 68. O calibration coefficients (T,K,A,B,C) are factory-entered, and are on the calibration sheet. H O reference mole fraction is in units of millimoles/mole of water vapor in the reference cell. Verify these values with the H O calibration sheet and change, if needed.
  • Page 51 FCT 04 04 Set Displays Function 04 performs functions 91-99. The LCD display has two lines, and each line can be configured to show any channel code 21-29 (CO ), 31-39 (H O), or 41-47 (MISC). As many as nine two-line display configurations can be defined by the Set Displays routine.
  • Page 52 FCT 05-06 05 Set D/A Conversion #1 Function 05 performs functions 81, 82, and 83. Digital to analog conversion DAC 1 Code= code #1. NEW= __ Digital to Analog Conversions may be performed on channel codes 22-27, 32-38, or 42. See function codes 80 - 83 for further details. *05X,low,high (where x is channel code 22-27, 32-38, or 42).

  • Page 53: Test Menu

    The D/A (Digital-to-Analog) Test is used to test the digital to analog conversion capabilities of the LI-6262. Enter a value (in volts), to be output to channel 1 or 2, which can be measured with a metering device.
  • Page 54 The EEPROM (Electrically Erasable Programmable Read-Only Memory) Test shows the amount of available ROM memory. The system parameters entered by the user are stored in EEPROM. The LI-6262 has approximately 32K bytes of ROM program memory. Geopotential - Displays the geopotential height in feet or meters, based on the current value of pressure at channel 43.
  • Page 55 FCT 08 Reset System - The software used in the LI-6262 is also used in the LI-6252 analyzer. By entering 1 for Yes you can change the configuration to that of a LI-6252 analyzer. This function is primarily for factory use only, so ordinarily this should not be changed.
  • Page 56 FCT 09 09 Integrate This function allows the area under a peak to be computed. When you press FCT 09, you are prompted for the following parameters: Prompt Description Source Ch= Channel code of the quantity to be integrated. When to start the integration. ‘On Exit’ will start On Exit Start = the integration immediately.
  • Page 57 FCT 09 where x is the quantity being integrated, and ∆t is the time between readings. At the end of the integration, the non-peak area is subtracted according to A = ∆t ΣX - (t )[(X )/2] where t and t are starting and ending times, and X and X are starting and...

  • Page 58: Print Commands

    FCT 09 Examples: µmol/mol absolute), Integrate channel 22 (CO *0922,2,.5,2 starting when it goes above 0.5 µmol/mol, and ending when it falls below 0.5 µmol/mol. Integrate channel 32 (H O mmol/mol absolute), *0932,1,1 starting immediately, and ending when the next * is received.
  • Page 59 FCT 11-13 11 Print Header Press FCT 11 to send a column header to the RS-232C port. The headers that are printed correspond to the channels specified by the Print List (FCT 13). Appendix D lists the labels for each channel code. Function 11 may be used at any time to output a single row of column headers.
  • Page 60 FCT 14-15 14 Auto Print Time interval between data Print T(s)=0 transmissions through the RS- NEW= __ 232C port. Enter specified interval in seconds (0.2, 0.5, or 1-3600) at which to transmit data (defined at FCT 13) to the RS-232C port. The interval can be 0.2, 0.5, or any value from 1 to 3600.
  • Page 61 FCT 16 16 Print Calibration Data Press FCT 16 to send the current calibration stack for H O, CO , and Miscellaneous channel codes to the RS-232C port. The output includes the calibration constants, auxiliary channel equations, and zero and span parameters for H O and CO .
  • Page 62 Parity - None, Even, or Odd. Check DTR (Data Terminal Ready) - Yes or No. This is a hardware handshaking line. The LI-6262 looks for DTR on pin 20. Check XON/OFF (Software Handshaking) - Yes or No. Controls the flow of data between transmitting and receiving devices.
  • Page 63 FCT 18-19 18 Reset Timer Press FCT 18 to reset the Timer function. The Timer (FCT 45)will begin counting again at zero. 19 Full Status Outputs the full status of the analyzer to the RS-232C port, in a format that can be read directly back into the analyzer, if desired.
  • Page 64 FCT 19 *74 1 *75 0.0000E+00 *76 0 *77 9.6805E+01 *78 1.5000E+00 *91 21,31 *92 23,29 *93 41,42 *94 31,32 *95 33,39 *96 43,44 *97 0,0 *98 0,0 *99 0,0 *19[n] (n is optional parameter for selecting just one output channel code).
  • Page 65 FCT 20-29 20 CO Enters menu at function 20. 20 ** CO2 ** ↑,↓,↵ 21-29 CO Channel Codes Press , followed by the appropriate code, to view the CO channel codes. These channels can only be viewed by pressing ; they are not executable from the main menu.
  • Page 66 FCT 30-39 30 H Enters menu at function 30. 30 ** H2O ** ↑,↓,↵ 31-39 H O Channel Codes Press , followed by the appropriate code, to view the H O channel codes. These channels can only be viewed by pressing ;...
  • Page 67 FCT 40-45 40 Miscellaneous Enters menu at function 40. 40 ** MISC ** ↑,↓,↵ 41-44 Temperature and Auxiliary Press , followed by the appropriate code, to view the temperature and auxiliary channel codes. These channels can only be viewed by pressing ;...
  • Page 68 FCT 46-49 46 Integration A During the integration (FCT 09), channel 46 shows the total area A under the peak from the last integration, or the accumulating area during the present integration. 47 Integration Peak Value Displays the peak value of the target channel obtained during the last integration, or the largest value so far during the present integration.
  • Page 69 FCT 50-59 50 CO Calibration Enters menu at function 50. 50 **CO2 CAL** ↑,↓,↵ 51-59 CO Calibration Stack The CO calibration stack (FCT 51-57) contains individual CO calibration reference in µmol/mol coefficients, as well as the prompt to enter the CO (FCT 59).
  • Page 70 FCT 60-68 60 H O Calibration Enters menu at function 60. 60 **H2O CAL** ↑,↓,↵ 61-68 H O Calibration Stack The H O Calibration stack (FCT 61-68) contains individual H O calibration coefficients, as well as the prompt to enter the H O reference (FCT 68).
  • Page 71 FCT 70-71 70 Set Miscellaneous Enters the menu at function 70. 70 ** MISC ** ↑,↓,↵ The 7x functions include those necessary for using the auxiliary input channel (#15 on the back panel terminal strip). The input signal is transformed by Y = A + Bx + Cx where x is the signal in mV, and the coefficients A, B, and C are entered in FCTs 71, 72, and 75.
  • Page 72 FCT 72-73, 75 72 Auxiliary B Auxiliary B value. Aux B= NEW= __ *72<B> 73 Auxiliary Destination Destination channel of auxiliary Aux Dest=0 input signal. NEW= __ The auxiliary channel input may be sent to channel codes 29 (CO reference), 39 (H O reference), or 43 (pressure).
  • Page 73 FCT 74 74 Average Time Signal averaging time. Avg(s)=0 NEW= __ Sets the software signal averaging time, from 0 to 30 seconds. Increasing the average time decreases the noise level in any displayed channel. The digital signal displayed is averaged over the entire time span set, after conversion from the analog signal.
  • Page 74 FCT 76 76 Vapor Flag Water corrections may be selected in the LI-6262 using FCT 76. The Vapor Flag default setting is for both pressure broadening and dilution corrections to be applied if a System Reset (FCT 08) is performed. See Sections 3.4 and 3.5 for complete explanations of the vapor corrections.
  • Page 75 NOTE: Barometric pressure may also be input in Setup command 03. Pressure may also be input continuously using the 6262-03 Pressure Transducer from LI-COR, or through connector #15 on the back panel terminal strip, as described in section 6.4. *77X (where x is the barometric pressure in kPa).
  • Page 76 There are two such channels (DAC 1, DAC 2) available on the instrument back panel. Three output ranges are available for DAC 1 and DAC 2 on the LI-6262 back panel terminal strip; 0-5V, 0-100 mV, and 4 to 20mA.
  • Page 77 FCT 80 The output resolution of X will be ∆X = 4.88 x 10 [voltage] ∆X = 2.44 x 10 [current]. If voltage is measured, the 0-5V range should be used whenever possible. The 0-100 mV range is provided for measuring or logging devices with a more limited voltage range;...
  • Page 78 FCT 81-83 81 D/A Conversion Code #1 Channel code for digital to DAC 1 Code= analog conversion #1. NEW= __ Enter channel code # 22-27, 32-38, or 42 as the channel to output through analog output channel #1. 82 D/A Conversion #1 Minimum Digital channel value which 1 0V= corresponds to 0V or 4mA on...
  • Page 79 FCT 84-86 84 D/A Conversion Code #2 D/A Conversion #2 (same as DAC 2 Code= 81). NEW= __ 85 D/A Conversion #2 Minimum Digital channel value which 2 0V= corresponds to 0V or 4mA on NEW= __ DAC #2. 86 D/A Conversion #2 Maximum Digital channel value which 2 5V= corresponds to full scale (5V,...
  • Page 80 FCT 90-99 90-99 Displays 90 ** DISP ** Enters menu at function 90. ↑,↓,↵ Nine two-line displays can be defined with functions 91-99. Function 91 defines display 1, accessed by pressing the "1" key, 92 defines display 2, etc. Displayable quantities are 21-29, 31-39, or 41-45. All displays can be defined in one operation at FCT 04, or they can be defined individually using FCT 91-99, as shown below.

  • Page 81: Section Vi. Interfacing

    SP AN ZE RO 6.1 General Information Data can be obtained from the LI-6262 in three ways: 1) from the display; 2) from the RS-232C port; or 3) from one of the analog output channels. RS-232C Output Up to 10 different channels can be output (in columnar form) at a user- specified time interval, or in response to a command (FCT 12).

  • Page 82: Rs-232C Data Transfer

    It is possible to damage a serial interface by connecting it to another type of interface. The RS-232C port on the LI-6262 is the female 25-pin "D" connector on the back panel labeled "RS-232C DCE". The LI-6262 is configured as Data...
  • Page 83 To test the cable connections and make sure that the computer software is configured properly, press FCT 16, which will print a list of the current calibration data for the LI-6262. If nothing is sent, make sure that the cable connections are correct, and consult the software manual for the software you are using.
  • Page 84 PC's and compatibles are PC TALK (Freeware, P.O. Box 862, Tiburon, CA 93920) and ProComm (Data Storm Technologies, Inc., P.O. Box 1471, Columbia, MO 65205). Either of these programs will allow ASCII data sent from the LI-6262 to be displayed on the computer terminal or stored in a disk file. Interfacing...
  • Page 85 Type the remote commands exactly as they appear on the command sheet. For example, typing * (asterisk)1530 will change the Auto Header command to 30 seconds in the LI-6262. The first two digits identify the channel to be edited, followed by appropriate arguments for that channel. The arguments may be channel numbers, calibration values, or flags (e.g.
  • Page 86 Note that you can create a complete configuration file for your LI-6262 by first capturing the data generated using remote command *19, and then editing the file (if desired). When this file is sent back to the LI-6262, it will configure all elements in its software.

  • Page 87: Analog Output

    Measuring Linear Analyzer Output The LI-6262 has two D/A Converters (DAC's), which can be used to convert calculated quantities (your choice of channels 22-27, 32-38, or 42) to an analog signal (-5V to +5V, -100mV to +100mV, or 4mA to 20mA ranges).
  • Page 88 Section 6 corresponds to zero volts (or 4mA), and the source channel value which corresponds to full scale voltage (or 20mA). For example, to configure DAC #1 to output a voltage signal proportional to , 100 µmol/mol full scale, press FCT 05 and set differential CO DAC 1 Code = 23 (Differential CO...
  • Page 89 Section 6 NOTE: The 20 mA signal will not go negative. If you wish to use the 20mA option, configure the DAC so that the signal will always be positive. For example, to allow a range of -100 to +100 µmol/mol, set = -100, rather than 0.
  • Page 90 Terminal Connections - Voltage Figure 6-1 shows an example connection of a data acquisition device to the LI-6262 to measure the linear output of channel #1. Connect the positive input of the data logger to the terminal labeled DAC1 5V (or DAC1 100mV).
  • Page 91 Terminal Connections -Current Figure 6-2 shows the proper connection of a data acquisition device to the LI-6262 terminal block. Connect the positive input of the data logger to the terminal labeled DAC1 20mA for channel one, or DAC2 20mA for channel two.
  • Page 92 Section 6 Measuring Raw (Non-Linear) Analyzer Output To measure the non-linearized voltage output of the CO or H O analyzer (0.1 second response time) with a meter or data logger: Connect the positive input of the data logger to the terminal labeled 0.1S or H O 0.1S (see Figure 6-3).

  • Page 93: Auxiliary Channel Inputs

    Use FCT 73 to designate which channel (29, 39, or 43) the analog signal will be sent to. Figure 6-4 shows how to connect a sensor to the terminal strip on the back panel of the LI-6262. NOTE: If the 6262-03 Pressure Transducer is installed in your analyzer, the auxiliary channel input is no longer available;...

  • Page 94: Temperature Output

    Section 6 The calibration equation is of the form Y = A + BX + CX , where A, B, and C are FCTs 71, 72, and 75, and X is the actual mV output of the sensor. See Section 5.3, FCT 70. 6.5 Temperature Output The analyzer temperature can be recorded by connecting a logging device to the terminal strip on the analyzer back panel.

  • Page 95: Using The 6262-03 Pressure Transducer

    Section 6 6.6 Using the 6262-03 Pressure Transducer The 6262-03 is located inside the LI-6262 case, and senses pressure from a manifold on the optical cell. Because the calibration function used in LI-COR gas analyzers will correct for pressure changes if the pressure in the optical cell is known, the 6262-03 allows for automatic pressure corrections to be performed.
  • Page 96 Section 6 as channel (Pressure). Specifying the Auxiliary Destination as channel 43 causes any constant pressure entered in FCT 77 to be ignored. The response curve for the pressure sensor is given by the equation Y = A + BX + CX where Y is the sensor output (in kPa), X is the mV output of the sensor, A is the Y-axis intercept, and B is the calibration multiplier, which is equal to the slope of the line representing the sensor’s response (Figure 6-7).
  • Page 97 Section 6 Aux A = FCT 71 NEW = 58.239 Aux B = FCT 72 NEW = 0.01510 Aux Dest FCT 73 NEW = 43 Aux C = FCT 75 NEW = 0 You can view the pressure value at FCT 43, and mV output at FCT 44. Both of these values can be viewed on a custom display, or sent via the RS-232C output to a printer and/or computer terminal.

  • Page 98: Section Vii. Maintenance

    Battery charging circuitry for the 6000B and 6200B batteries is built into the LI-6262, and requires only that the AC line cord be connected. If you are charging one 6000B battery, it will take 1 1/2 - 2 hours (3 - 4 hours for the 6200B) to recharge the battery to 80-90% of full capacity (with the LI-6262 power switch off).

  • Page 99: Internal Soda Lime/Desiccant

    Peltier coolers controlling the detector temperature are powered up. There is a small plastic bottle inside the LI-6262 that contains a mixture of soda lime and anhydrous Mg(ClO (magnesium perchlorate).
  • Page 100 Section 7 The spare soda lime/desiccant Viton gasket in lid bottle (in the spare parts kit) is shipped without chemicals. You will need to procure chemicals Polyester fiber in bottle locally. When handling chem- WARNING icals, observe all manufacturer’s safety warnings. Fill the bottle slightly more than half full with soda lime.

  • Page 101: External Soda Lime/Desiccant

    H O in absolute mode, the external soda lime/desiccant will need to be changed every 24-48 hours of operation. For additional information on operating the LI-6262 in this mode, refer to Section 4.4, H O Absolute Mode Caution. Maintenance...
  • Page 102 Make sure that the filter paper discs on either end cap are not clogged (reduces flow rate) or torn. Adhesive-ringed replacement discs are included in the spare parts kit (LI-COR part # 9960-040). Magnesium perchlorate cannot be regenerated after use. Dispose of properly.

  • Page 103: Fan Filter

    The 2 amp fast blow fuse is for the external batteries. If the LI-6262 fails to turn on, check the fuse for the power source you are using (battery or AC). If the analyzer continually blows fuses it is in need of repair.

  • Page 104: Section Viii. Troubleshooting

    Trouble- O A N A L Y Z SP AN ZE RO ↑ EE X, ↓ shooting SP AN ZE RO This section summarizes some things that might go wrong, and suggests what to do about these problems should they happen. Power ON Problems.
  • Page 105 Section 8 Zero and/or Span Adjustments Difficult to Set. If the zero and/or span adjustments are difficult to set, check to see that the analyzer is configured correctly (jumper tubes, soda lime/desiccant, etc.). Also check to make sure that the flow through the analyzer is first entering the portion of the scrubber tube assembly containing the soda lime, not the magnesium perchlorate.
  • Page 106 O A N A L Y Z Specifications SP AN ZE RO ↑ EE X, ↓ SP AN ZE RO Type: Differential, non-dispersive infrared gas analyzer. H O or CO channels can be independently configured for operation in either differential or absolute mode.
  • Page 107 Keypad: 16-key keypad for selecting software functions and entering numbers. Hose Connections: Rapid connect hose fittings for 4 mm ID × 6 mm OD plastic tubing. Temperature Range: 0-50 °C ambient, 0-50 °C optical bench temperature. Power Requirements: 100-130 VAC or 200-260 VAC (47-65 hertz), or 10.5 - 16 VDC, 1.5 amp maximum.
  • Page 108 6262-03 Pressure Transducer Specifications Pressure Range: 0 to 115 kPa absolute. Accuracy (with software correction): ± 0.1% full scale. Resolution: 0.002 kPa. Signal noise (peak-to-peak): 0.002 kPa typical. Power consumption: 50 mA (steady state). Weight: 0.88 oz. (25 g). Specifications...
  • Page 109 FAX: 614-881-5989 <8% water) Toll free: 800-858-9682 Fisher Scientific 711 Forbes Avenue Soda Lime: Part #S201-212 Pittsburgh, PA 15219-4785 (LI-COR Part #9960-071) Phone: 201-467-6400 FAX: 201-379-7415 : Part #M54-500 (500g) Mg(ClO Toll free: 800-776-7000 Toll free FAX: 800-926-1166 Thomas Scientific P.O.
  • Page 110 Software O A N A L Y Z SP AN ZE RO ↑ EE X, Commands ↓ SP AN ZE RO Function Code Description Page **SETUP** Set CO Calibration Set H O Calibration Set Miscellaneous Set Displays Set D/A Conversion #1 Set D/A Conversion #2 Backlight ON/OFF Test Menu...
  • Page 111 Function Code Description Page **H2O** 5-21 O raw mV 5-21 O mmol/mol absolute 5-21 O mmol/mol differential 5-21 O kPa absolute 5-21 O kPa differential 5-21 O mg/g absolute 5-21 O mg/g differential 5-21 O dewpoint °C 5-21 O mmol/mol reference 5-21 **MISCELLANEOUS** 5-22...
  • Page 112 Function Code Description Page **MISCELLANEOUS** 5-26 Auxiliary A (Offset) 5-26 Auxiliary B 5-27 Auxiliary Destination 5-27 Average Time 5-28 Auxiliary C 5-27 Vapor Flag 5-29 Pressure 5-30 Vapor Correction a 5-30 **DAC** 5-31 D/A Conversion Code #1 5-33 D/A Conversion Code #1 Min. 5-33 D/A Conversion Code #1 Max.
  • Page 113 EE X, Headers ↓ SP AN ZE RO The following table shows the way in which channel code headers will appear when sent from the LI-6262 to a terminal or printer through the RS-232C port. Header Description Channel Code C2 mV raw mV C2 µm/m...
  • Page 114 Console O A N A L Y Z SP AN ZE RO ↑ EE X, Commands ↓ SP AN ZE RO Setup Commands 00 **SETUP** 10 **PRINT** 01 Set CO Calibration 11 Print Header 02 Set H O Calibration 12 Print Data 03 Set Miscellaneous 13 Set Print List 04 Set Displays...
  • Page 115 Calibration and Configuration Stacks 50 **CO2 CAL** 60 **H2O CAL** 51 CO Calibration T 61 H O Calibration T 52 CO Calibration K 62 H O Calibration K 53 CO Calibration A 63 H O Calibration A 54 CO Calibration B 64 H O Calibration B 55 CO...
  • Page 116 Remote Commands Function Type the following on a computer or terminal (comments). 01 Set CO Calibration *01T,K,A,B,C,D,E,REF,VAPOR FLAG 02 Set H O Calibration *02T,K,A,B,C,REF 05 Set D/A Conversion Code #1 *05x,low,high (x is channel code 22-27, 32-38, 06 Set D/A Conversion Code #2 *06x,low,high (same as 05) 07 Backlight *07Y (Yes) or *07N (No) to turn backlight...
  • Page 117 Saturation Vapor O A N A L Y Z SP AN ZE RO ↑ EE X, ↓ Pressure Table SP AN ZE RO Temp.°C 6.11 6.12 6.20 6.24 6.29 6.34 6.38 6.43 6.48 6.52 6.57 6.62 6.66 6.71 6.76 6.81 6.86 6.91 6.96...
  • Page 118 Connector O A N A L Y Z SP AN ZE RO ↑ EE X, ↓ Descriptions SP AN ZE RO 25 Pin RS-232C DCE Port Pin # Name Frame ground Received data Transmitted data Request to Send Clear to Send Data Set Ready Signal Ground Carrier Detect...
  • Page 119 H O concentrations. The CO calculations use the water correction equations described in Section 3. gascomp.c - Implements LI-COR IRGA equations #include <stdio.h> #include <math.h> static double ppm(double mV, double Cr, double Tirga, double vp_r, double vp_s, double kPa);...
  • Page 120 vp_r - reference cell vapor pressure (kPa) vp_s - sample cell vapor pressure (kPa) kPa - total pressure (kPa) double Vref, gain, chi_ws, chi_wr, eff_cr, tc, eff_mv, result, inv_cal; tc = temp_correction(Tirga); if (Cr == 0.0) { /* absolute mode chi_ws = chi(vp_s/kPa);...
  • Page 121 static double temp_correction(double t) return (t + 273)/(T_cal + 273); /* ------------------------------------------------------------------------- */ static double inverse_cal(double cppm) /* returns the mV that would be generated if in absolute mode with cppm in the sample cell double mv_old = 0, mv, c; /* crude first guess if (water_flag) mv = cppm/75 * 5000;...
  • Page 122 1 + (Water_A -1) * mfw; /* ------------------------------------------------------------------------- */ static double p0_over_p(double kPa) if (water_flag) /* return (101.3 / kPa) * 0.88451 + 0.10889; */ /* The LI-6262 approx. */ return pow(101.3 / kPa, 0.9); else return 101.3 / kPa;...
  • Page 123 water_flag = 0; T_cal = Cal_temp; K_cal = Cal_k; A_cal = coeffs[0]; B_cal = coeffs[1]; C_cal = coeffs[2]; D_cal = coeffs[3]; E_cal = coeffs[4]; Water_A = water_corr_a; if (vapor_correct_flag == 0) { vap_ref = 0; vap_samp = 0; Cs = ppm(mv, ref, temp, vap_ref/1000.0*pressure, vap_samp/1000.0*pressure, pressure);...
  • Page 124 Returns water vapor concentration in mmol/mol double Ws; water_flag = 1; T_cal = Cal_temp; K_cal = Cal_k; A_cal = coeffs[0]; B_cal = coeffs[1]; C_cal = coeffs[2]; D_cal = 0; E_cal = 0; Ws = ppm(mv, ref, temp, 0, 0, pressure); return Ws;...
  • Page 125 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...
  • Page 126 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.
  • Page 127 ® 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) E-mail: envsales@env.licor.com Internet: http://www.licor.com...

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