LI-COR LI-7700 Instruction Manual
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LI-COR LI-7700 Instruction Manual

Open path ch4 analyzer
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LI-7700
Open Path CH
Analyzer
4
Instruction Manual

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  • Page 1 LI-7700 Open Path CH Analyzer Instruction Manual...
  • Page 2 LI-7700 Open Path CH Analyzer Instruction Manual LI-COR, Inc. 4647 Superior Street P.O. Box 4425 Lincoln, NE 68504-0425 Telephone: (402) 467-3576 FAX: 402-467-2819 Toll Free: 1-800-447-3576 (U.S. & Canada) Email: envsales@licor.com envsupport@licor.com www.licor.com ®...

  • Page 3: Declaration Of Conformity

    Lincoln, Nebraska 68504 USA Phone: 402-467-3576 FAX: 402-467-2819 Information: 1-800-447-3576 (Toll-free U.S. & Canada) E-mail: envsales@env.licor.com Declaration of Conformity Manufacturer’s Name: LI-COR, Inc. Manufacturer’s Address: 4647 Superior Street Lincoln, Nebraska USA 68504 declares that the product Product Name: Open Path CH Gas Analyzer...
  • Page 4 The LI-7700 is covered by U.S. patents, patents pending, foreign equivalents, and Austrailian patent AU2009292601. LI-COR has licensed certain aspects of the LI-7700 that were developed with expertise from Southwest Sciences, Inc. (Santa Fe, NM). This project was funded in part by the US Department of Energy through a Small Business Innovation Research grant (DE-FG02-05ER84283).
  • Page 5 Notes on Safety This LI-COR product was designed to be safe when operated in the manner described in this manual. The safety of the product cannot be guaranteed if the product is used in any other way than is specified in this manual.

  • Page 6: Table Of Contents

    Install the LI-7700 Computer Software ..............1-9 Power On ......................... 1-9 Connect the Ethernet Data Cable ................1-10 Launch the Software and Connect to an LI-7700............. 1-11 Mirrors - Cleaning and Care ................... 1-12 2 Operation Introduction to the LI-7700 Interface Software ............2-1 Main View ........................
  • Page 7 Connecting to the LI-7700 and LI-7550 (Ethernet) ............. 3-6 Getting an LI-7700 to talk to an LI-7550..............3-7 Using an LI-7700 with an LI-7500A or LI-7200 CO O Analyzer......3-9 Connecting to the LI-7700 and LI-7550 (RS-232 Serial) ........... 3-11...
  • Page 8 4 Data Files File Header....................... 4-1 Data ......................... 4-2 Diagnostics Header ....................4-4 Status Columns ......................4-6 5 Making Flux Measurements with the LI-7700 Computing Fluxes..................... 5-2 Example Calculation....................5-5 Full Computation ...................... 5-5 Simplified Computation .................... 5-7 Finding Multipliers....................5-8 Low Resolution Look-up Tables ................
  • Page 9 Manual Line Lock Example ..................7-5 Re-enabling Automatic Line Lock................7-7 Networking ......................7-7 Enabling IPv6 on Windows XP .................. 7-7 The LI-7700 Finder Application ................7-8 Communications Grammar ..................7-14 Introduction ......................7-14 LI-7700 Communications..................7-14 Element Descriptions ....................7-15 Grammar ........................
  • Page 10 Appendix B. Maintenance ..................8-4 Changing the Internal Desiccant Bottle ..............8-4 Changing the Thermocouple..................8-6 Changing the LI-7700 Fuse ..................8-7 Changing the LI-7550 Fuse ..................8-7 Appendix C. Troubleshooting ................... 8-8 Appendix D. Suppliers.................... 8-11 Chemical Sources ....................8-11 Calibration Gases ....................

  • Page 11: Welcome

    Welcome… …and thank you for your purchase of the LI-7700 Open Path CH Analyzer. We welcome your comments, questions, and suggestions. Feel free to contact us at any time. LI-COR, Inc. 4647 Superior Street P.O. Box 4425 Lincoln, Nebraska 68504-0425 Phone: 402-467-3576 ●...
  • Page 12 United States is manda- tory. The label that must be attached to laser products marketed in the United States is located on the side of the lower housing of the LI-7700 Open Path CH Analyzer (Figure 2), indicating compliance with CDRH regulations.

  • Page 14: General Information

    Contact LI-COR if you have questions about the suitability of the LI-7700 in your application. Figure 1-1 shows a schematic of the LI-7700 sensor and the Herriott cell. Except for the desiccant bottle, thermocouple, and fuse, which are accessible externally, there are no user-serviceable parts in the sensor.

  • Page 15: What's What

    General Information What’s What If you have just taken delivery of your LI-7700, check the packaging list to verify that you received everything that was ordered. The standard LI-7700 will include: The LI-7700 Open Path CH Analyzer • LI-7700 Open Path CH Analyzer –...

  • Page 16: Spares Kit And Cables

    Ethernet hub, or the Ethernet port on your computer. • Power Cable (p/n 9975-030) – Used to connect the LI-7700 to a 10.5 to 30 VDC power supply. The power cable has 4 wires: brown and white are tied to a black lead, which connects to the negative (-) power supply terminal;...
  • Page 17 Mounting Hardware – This is the hardware required to mount the LI-7700 on typical platforms. It includes the mounting post and two hex screws that secure the post to the base of the LI-7700 analyzer. The post and screws are affixed to the analyzer prior to shipping.

  • Page 18: 7550-101 Auxiliary Sensor Interface (Optional)

    Gill WindMaster /Pro or a Campbell® Scientific, Inc. CSAT3 directly to the analog input on the LI-7700 and/or LI-7550. These cables terminate with a Gill or Campbell® bulkhead connector on one end and Turck bulkhead connector(s) on the other (for connecting to the LI-7700 and/or LI-7550).

  • Page 19: Li-7550 Analyzer Interface Unit (Optional)

    General Information LI-7550 Analyzer Interface Unit (optional) The LI-7550 enhances the functionality of the LI-7700 by providing onboard data logging of eddy covariance data sets (CH , U, V, W, T , and other variables) to a removable USB data storage device and enabling versatile data output options. Detailed instructions for the LI-7550 are provided in Chapter 3.

  • Page 20: Li-7700 Components And Connections

    Lower Housing – houses the digital signal processing electronics and spin motor (see Figure 1-1). 10. Connection Panel – has indicator LEDs, weather-proof cable connections, and an external network reset button (see Figure 1-7). Figure 1-6. The LI-7700 Open Path CH Analyzer. Instruction Manual Version 2...
  • Page 21 Figure 1-7. The connection panel on the LI-7700. well as three type E thermocouple connections. This data is output with the LI-7700 data stream. Washer Power – supplies power to the external washer unit accessory. Ethernet Connection – port for Ethernet communication.

  • Page 22: Basic Setup

    The LI-7700 powers on immediately after power is supplied. It may take 30 seconds or more to boot up, and the power and status LEDs on the bottom of the LI-7700 will illuminate after instrument completes start-up.

  • Page 23: Connect The Ethernet Data Cable

    RJ45 connector to an Ethernet port on a computer or your computer network. If you are using the LI-7700 with an LI-7550 Analyzer Interface Unit, rather than attaching the 0.3 m cable, attach the vacant terminal of the 5 m cable to one of the LI-7550 ports labeled “Ethernet.”...

  • Page 24: Launch The Software And Connect To An Li-7700

    Basic Setup Launch the Software and Connect to an LI-7700 Start the LI-7700 application: either double click the LI-7700 software icon on your computer’s desktop or launch the software from your computer’s Start menu. Click on the Connect button and a “Connect” dialog box will appear.

  • Page 25: Mirrors - Cleaning And Care

    As a general rule, if the cleaner is safe for automotive finishes, it is probably safe to use in the LI-7700 washer reservoir. The washer should be filled with windshield washer fluid with a temperature rating suitable for the environment in which it will be deployed.

  • Page 26: Operation

    Introduction to the LI-7700 Interface Software Main View After connecting to an LI-7700, the software window should look similar to the image below. The graphs are set to auto-scale the y-axis by default, so do not be alarmed by the appearance of “noisy” signals.

  • Page 27: Tool Bar

    The tool bar buttons activate the following options: Manual Controls are Click the Connect button the basic configuration to establish communication options for the LI-7700, The Help button opens a with an LI-7700. Discon- including settings for menu with “About” and...

  • Page 28: Settings Bar

    Introduction to the LI-7700 Interface Software Settings Bar Four groups of settings and operation parameters are displayed in this portion of the main window: The Charting frame The Status frame indicates the status of operating parameters. Signal Path is Clear: green indicates normal operation; red indicates the provides access to graph settings.
  • Page 29 Operation About the LI-7700 Dialog Boxes The Manual Controls, Charting, Auxiliary Inputs, Outputs, PC Logging, and USB Log- ging dialogs include OK, Cancel, and Apply buttons. In these dialogs, click OK to implement changes and close the dialog, Cancel to close the dialog without implementing changes, or Apply to implement changes and keep the dialog open.
  • Page 30 Introduction to the LI-7700 Interface Software About charting In the Configure Graphs dialog you can turn automatic scaling “on” or “off” with the Auto-scale check box. When automatic scaling is on, the software retains a record of the maximum and minimum values encountered and scales the graph accordingly. If you click the Clear Charts button in the main window the chart scaling will reset.

  • Page 31: Configuring The Li-7700

    The following sections describe PC/Network data logging, operating temperature range settings, mirror cleaner settings, and mirror heater settings. When the LI-7700 settings are changed, they are implemented to whichever LI-7700 is connected to the interface. After changing the configuration, you could unplug the instrument and deploy it in the field.

  • Page 32: Logging Status Columns

    Configuring the LI-7700 Choose a directory that the files will be written to, choose whether to log the “Status” record, and whether it will be part of the data file or a separate log file. Choose how often to split the log files (from 15 minutes to 24 hours). Click Apply.

  • Page 33: Operating Temperature Range

    °C (warm). Select the temperature range setting that reflects the expected temperatures in the environment where you will deploy the LI-7700. If the wrong temperature setting is selected, the instrument may be unable to maintain the required temperature in the internal controls, and thus lose line lock (and it will not record methane data).

  • Page 34: Manual Controls

    Change the settings as desired and then click Apply or OK. Any changes will be implemented immediately to the connected LI-7700. These settings will be saved in the LI-7700 or they can be saved as a configuration file (see page 2-19).

  • Page 35: Configuring Mirror Heater Controls

    Start Time and Stop Time specify when the mirror heaters are on. These are available only when the Control Settings are Automatic. With the settings shown above, the LI-7700 will deliver 7% of the maximum possible heater power, as needed to keep the mirror 2 °C above ambient temperatures between 6:00 pm (18:00) and 6:00 am (06:00) to the upper mirror.
  • Page 36 Configuring the LI-7700 Determining Mirror Heater Settings The mirror heaters serve to remove/prevent the buildup of condensation on the mirrors. Determining what mirror settings are best for your application/environment is best done with some experimentation. The following guidelines should serve as a...

  • Page 37: Configuring The Spin Motor Control

    Spray Duration: can be set from 0 to 110 seconds. A setting of 0 will result in no spray, but the mirror will still spin for 10 seconds if the RSSI is below the signal strength threshold. 2-12 LI-7700 Open Path CH Analyzer...
  • Page 38 Configuring the LI-7700 With the settings shown above, if the signal strength is below 20%, the LI-7700 will initiate a 20 second cleaning cycle starting at 4:00 am (04:00). If the first cleaning cycle fails to raise the signal strength to above 20%, it will repeat every hour until 8:00 pm (20:00) or until the signal strength is above 20%.
  • Page 39 Spray Duration: 20 Sec The LI-7700 will check the signal strength (RSSI) every hour. If the RSSI is below 10%, the analyzer will initiate a 30 second cleaning cycle, which is 20 seconds of spray + spin then 10 seconds of spin only. Disadvantages: If the mirror becomes very dirty and cannot be cleaned, the washer fluid reservoir will become empty after 45 cleaning cycles.

  • Page 40: Instrument Name And Address

    10%), data could be lost until the mirror is cleaned, which will begin at 1:00 am. Instrument Name and Address To rename your LI-7700, simply type the new name of your LI-7700 into the name field and click “OK” or “Apply.” Then reboot the instrument.

  • Page 41: Setting The Time

    Operation Setting the Time The LI-7700 is shipped with the time set at the factory. To set your local time: Connect to the LI-7700. Open the Manual Controls dialog box. Set the PTP: field to “automatic.” Select the desired time zone.
  • Page 42 Best Master Clock algorithm. The LI-7700 should use this setting in most circumstances. Preferred: The LI-7700 uses its own internal clock unless it finds a better clock on the network. The LI-7550 should use this setting in most circumstances.

  • Page 43: Output Rate

    The output rate setting determines the signal averaging done by the digital filter. To avoid aliasing (only a concern for co-spectra, not for fluxes), the LI-7700 output rate should be set at a frequency greater than or equal to 2 times the desired bandwidth, also referred to as the Nyquist frequency (e.g., for a bandwidth of 20 Hz, set the output rate...

  • Page 44: Configuration Files

    Note: when you connect to an LI-7700, at the top of the “Connect” dialog box, there is a “Use Instrument Configuration” check box. Be sure that this is checked in order to avoid overwriting the current LI-7700 configuration.

  • Page 45: Li-7700 Analog Inputs

    • (7550-101 req’d) 5V source (10 mA max.) Figure 2-3. The 7550-101 can function as a weather-proof terminal strip for the LI-7700 Analog In- put (Option 1), the LI-7550 Auxiliary Input (Option 2), or the LI-7550 DAC Output (Option 3).

  • Page 46: Auxiliary Sensor Interface Terminals (Option 1)

    The interior of the interface is shown in Figure 2-4. There is a small jumper located at the LK1 label; when using the 7550-101 with the LI-7700 (Option 1), position the jumper over the 2 pins nearest the LI-7700 label (the lower two pins in Figure 2-4).
  • Page 47 The terminal positions are numbered and configured as follows, reading from left to right: Table 2-1. Terminal assignments for the 7550-101 and wire colors for the Analog Input/Output cable when using the LI-7700 analog inputs (Option 1). Option 1 Analog In/Out...

  • Page 48: Connecting Sensors To The Auxiliary Sensor Interface

    LI-7700 Analog Inputs Connecting Sensors to the Auxiliary Sensor Interface There are 5 “gland” type plugs on the Auxiliary Sensor Interface top cover that secure and seal the wires that are connected to terminals inside the box. To attach your...

  • Page 49: Thermocouple Inputs

    To avoid risk of these issues, shield the auxiliary sensor interface from direct sun and/or thermally insulate the apparatus. A simple solution is to wrap the Auxiliary Sensor Interface with aluminum foil. 2-24 LI-7700 Open Path CH Analyzer...

  • Page 50: Configuring Auxiliary Inputs (Li-7700)

    Configuring Auxiliary Inputs (LI-7700) Analog inputs are configured from the “Configure Auxiliary Inputs” dialog box (click ). Auxiliary inputs 1 through 4 are used with LI-7700 inputs (see Option 1, page 2-21). They are configured with the top four tabs in the Configure Auxiliary Inputs dialog box.
  • Page 51 Using Aux4 to log the speed of sound, the terms a1=340 (offset), a2=6.5536 (slope) are given in the CSAT3 Instruction Manual. This is shown below. Refer to the CSAT3 Instruction Manual for more information. LI-7700 Aux Channel Aux1 Aux2 Aux3...

  • Page 52: Deploying The Li-7700 And Accessories

    The LI-7700 mounting post is designed to fit securely into a 1” crossover fitting, similar to those used in many micrometeorological stations. Crossover fitting suppliers are listed on page 8-14.

  • Page 53: Positioning The Li-7700

    Operation Positioning the LI-7700 There are numerous factors to take into account when deploying the LI-7700 in eddy covariance flux applications. Addressing these concerns appropriately is critical to minimizing required frequency response corrections. Here we address two of these: instrument height above the canopy and High above the plant canopy: proximity to the sonic anemometer.

  • Page 54: Grounding

    Deploying the LI-7700 Grounding The power supply, Ethernet, and analog inputs are all electrically isolated from each other and from the internal circuitry. There also are protection clamps in the form of spark gaps on the isolated circuits to the instrument chassis. For lightning protection, make sure the mounting structure for the instrument is electrically grounded, or run an independent bonding wire from the instrument mount to the earth.

  • Page 55: Attaching The Mirror Cleaner/Washer Assembly

    Attaching the Mirror Cleaner/Washer Assembly Follow the steps below to attach the mirror cleaner. Attach the spray nozzle assembly (p/n 9977-032) to a spar on the LI-7700, as shown below. It snaps into place. Attach the “Quick Connect” hose fitting on the nozzle/hose assembly to the fitting on the washer reservoir (p/n 7700-101).

  • Page 56: Mounting The Washer Reservoir

    The cables and hose are 5 meters long. The washer reservoir must be within 5 meters of the LI-7700. The pump is powerful enough to lift the washer fluid 5 meters, but attempts to lengthen the washer hose will result in reduced fluid pressure, which will affect the performance of the pump and mirror cleaner.
  • Page 57 , ancillary, and diagnostic data) Earth Ground Figure 2-9. A typical field deployment of the LI-7700 and accessories. For eddy covariance flux applications, water vapor flux must also be measured. This can be accomplished with an LI-7500, LI-7500A or LI-7200 CO O Analyzer (not shown).

  • Page 58: Operation With The Li-7550 Analyzer Interface Unit

    Operation with the LI-7550 Analyzer Interface Unit Introduction to the LI-7550 The LI-7550 is available as an accessory for the LI-7700 Open Path CH Analyzer. When used with the LI-7700 it provides: • Logging of eddy covariance data sets to a removable USB storage device.

  • Page 59: What's What

    (0.3m) Ethernet adapter cable (p/n 392-10107). The short cable is terminated with an RJ45 Ethernet connector, which plugs into an Ethernet wall socket or a computer’s Ethernet port. LI-7700 Open Path CH Analyzer...
  • Page 60 Auxiliary Interface Unit (p/n 7550-101) can be used in place of this cable. Use of the 7550-101 with the LI-7700 is described in the previous chapter, and with the LI-7550 is described later in this chapter. Note that only one Analog Input/Output cable is included with the LI-7550.

  • Page 61: Cable Connections

    Inc. (Minneapolis, MN, see page 8-13). If you need longer cables, several custom-length cables can be purchased from Turck, Inc. Table 3-1 below lists both LI-COR part numbers and the corresponding Turck part numbers for each cable. You can also construct your own extension cables.
  • Page 62 PIN 12 VIOLET USB LOGGING - USE INDUSTRIAL GRADE ONLY! SOLID LED - DRIVE MOUNTED, NOT LOGGING LI-COR Biosciences RAPID BLINK - LOGGING 4647 Superior St. Lincoln, NE 68504 SLOW BLINK - ERROR. EJECT AND RETRY 1-800-447-3576 (U.S. & Canada)

  • Page 63: Basic Setup

    Turck® connections on both ends. Attach one terminal to the Ethernet connection on the LI-7700 and the other to either the Ethernet 1 or 2 terminals on the LI-7550 connection panel (see Figure 3-2). You can now connect the LI-7550 to a...

  • Page 64: Getting An Li-7700 To Talk To An Li-7550

    LI-7500A or LI-7200 CO O Analyzer. You can follow the steps below to get the LI-7700 to talk to the LI-7550. Alternatively, you can follow a simplified procedure described in the LI-7500A and LI-7200 instruction manuals. See page 3-9 for more information.
  • Page 65 Operation with the LI-7550 Analyzer Interface Unit In the “Factory Setup” dialog box you should see both the LI-7700 and the LI-7550, similar to the figure below. Click on the LI-7550, then click the Config LI-7550 button. In the resulting dialog box, confirm that the text in the field called “Head:”...

  • Page 66: Using An Li-7700 With An Li-7500A Or Li-7200 Coo

    LI-7550 Analyzer Interface Unit. One version is specifically for using the LI-7550 with an LI-7700. If you ordered an LI-7700 with an LI-7550 (but not an LI-7500A or LI-7200), the LI-7550 will have the LI-7700 software installed.
  • Page 67 Auxiliary Inputs, opening the “Configure LI-7550 Outputs” dialog, or opening the USB… dialog from the LI-7700 application. Conversely, if the LI-7550 is formatted to operate with an LI-7700, you will have access to all functions in the software, but it will be unable to communicate with an LI-7500A/7200.

  • Page 68: Connecting To The Li-7700 And Li-7550 (Rs-232 Serial)

    392-10268 Connector Figure 3-5. RS-232 Cable configuration for the LI-7700 and LI-7550. The Ethernet data cable is still used to connect the LI-7700 to the LI-7550, while the RS-232 cable connects the LI-7550 to the computer. Instruction Manual Version 2...

  • Page 69: Using The Li-7550

    Using the LI-7550 The LI-7550 is configured through the LI-7700 software. When settings are configured in the LI-7700 software, this information is stored in the LI-7700. Then the LI-7550 pulls this information from the LI-7700 when the two components are connected and powered up.
  • Page 70 Using the LI-7550 In the “Configure USB Log Data” dialog box, select the variables that you would like to log and click Apply. Auxiliary Inputs 1-4 and Thermocouple Inputs 1-3 are described on page 2-21 (Option 1), and Auxiliary Inputs 5-8 are described on page 3-16 (Option 2).

  • Page 71: About Usb Devices

    Table 3-2 shows approximately how long the LI-7700 can store data before a 4 GB USB drive becomes full. Table 3-2. Approximate number of days that the LI-7700 can record data before a 4 GB flash drive becomes full.

  • Page 72: Analog Inputs (Li-7550)

    LK1 jumper is positioned over the two pins nearest the LI-7550 label. Refer to page 2- 21 for information on the LI-7700 analog inputs (Option 1). Below we describe how to configure the 7550-101 and the corresponding wires/pins in the Analog Input/Output Cable for LI-7550 analog inputs.

  • Page 73: Auxiliary Sensor Interface Terminals (Option 2)

    (near the LI-7700 LI-7550 LI-7550 label) for the 360-09333 Rev 2 LI-7550 analog inputs Made in USA or outputs. www.licor.com Figure 3-7. Schematic of the Auxiliary Interface Unit interior. 3-16 LI-7700 Open Path CH Analyzer...
  • Page 74 Using the LI-7550 The terminal strips connections are shown below: When Used for Analog Inputs (LI-7550) Figure 3-8. Terminal connections for analog inputs (Option 2). Table 3-3 shows Auxiliary Sensor Interface input assignments and corresponding wire colors for the input cable. Table 3-3.

  • Page 75: Electrical Connections

    LI-7550 analog outputs are electrically isolated from the LI-7550 power input and isolated from the analog inputs. For additional 7550-101 & Analog Input/Output usage instructions, refer to the follow- ing pages: • LI-7700 Inputs (Option 1) instructions: page 2-21 • Wiring instructions: page 2-23 • Mounting instructions: page 2-29 •...

  • Page 76: Analog Input Time Delays

    Data from Auxiliary Inputs 5-8 (available only on the LI-7550) have a fixed time delay of 1 second. These values are shifted together in the data files by 1 second from data acquired with the LI-7700, Auxiliary Inputs 1-4, and the thermocouple inputs. Instruction Manual Version 2...

  • Page 77: Li-7550 Clock

    Operation with the LI-7550 Analyzer Interface Unit LI-7550 Clock The LI-7550 clock is separate from the LI-7700 clock, but it also uses Unix (POSIX) time and the Precision Time Protocol (see page 2-16) unless the LI-7550 is configured for an LI-7500A or LI-7200. When the two components are used together, set the LI-7700 clock to “automatic”...

  • Page 78: Li-7550 Outputs

    Campbell® Scientific, Inc datalogger. To log the SDM output from the LI-7700, first set up the LI-7700 using the Windows® software, then program the datalogger to poll the LI-7700 for data. The blue wire (SDM_DATA) should be connected to datalogger terminal C1, white (SDM_CLK) to terminal C2, and brown (SDM_EN) to C3.
  • Page 79 SDM Address specifies the SDM address of the LI-7700 and needs to match the address set in the LI-7700 software, and Mode refers to the data that will be retrieved from the LI-7700. Seven data modes are available (Table 3-4.).
  • Page 80 LI-7550 Outputs CH4D (mmol/m Methane number density Data-normal PRESSURE (kPa) Pressure measured by the LI-7700 with fast TEMP (°C) Temperature measured by the LI-7700 thermocouple auxiliaries DIAG Diagnostic value, an integer RSSI Signal strength (Residual Signal Strength Indicator (0- AUX1 100%)
  • Page 81 Percentage of 1000 Hz scans dropped (0-100%) LCTSETPT Laser cooler temperature, measured (°C) BCTACTUAL Laser cooler temperature, set point (°C) BCTSETPT Block cooler temperature, measured (°C) OPTICSRH Block cooler temperature, set point (°C) Relative humidity in the upper dome (0-100%) 3-24 LI-7700 Open Path CH Analyzer...

  • Page 82: Rs-232

    Click the Configure LI-7550 Outputs button ( ) for access to the outputs dialog. The RS-232 tab is used to set the LI-7700 RS-232 port configuration for serial data output. After selecting the desired variables click Apply; the LI-7700 will begin to send data out the RS-232 port according to these parameters.

  • Page 83: Analog

    (in the Manual Controls window, see page 2-9). Configure your data storage device to sample at a rate that is equal to or greater than the LI-7700 output rate. Note: The LI-7700 analog output signals update at 300 Hz to minimize jitter.

  • Page 84: Analog Output Time Delays

    LI-7550 Outputs Analog Output Time Delays The analog outputs on the LI-7550 are delayed by 1 second to account for network latencies. The total delay at a particular output rate is increased by the averaging filter according to the expression: −...
  • Page 85 DAC channel 6 positive Pink Pin 6 READY Analyzer Ready Blue Pin 7 Ground Black Pin 11 No connection Pin 8 Ground Violet Pin 12 No connection Orange Pin 9 Ground Pin 10 Analog Outputs 0-5V 3-28 LI-7700 Open Path CH Analyzer...

  • Page 86: Mounting The Li-7550 Analyzer Interface Unit

    Mounting the LI-7550 Mounting the LI-7550 Analyzer Interface Unit Two brackets (p/n 6575-033) are included with the LI-7550 that can be used to mount it to a tripod or other post, using bolts or U-bolts. There are holes in the four corners of the box, as well, that can be used to attach the box directly to a flat surface.
  • Page 87 Washer Reservoir Earth Ground Figure 3-11. A typical field deployment of the LI-7700 and accessories. For eddy covariance flux applications, water vapor must also be measured. This can be accomplished with an LI-7500, LI-7500A or LI-7200 CO O Analyzer (not shown).

  • Page 88: Data Files

    … … … … … … … File Header The header is part of every data file produced by the LI-7700. It includes the following fields: Table 4-1. Data file header. Header Label Description Model: Analyzer File Type: Header content descriptor (usually 2)

  • Page 89: Data

    Therefore, it is not necessary to output date and time unless you wish to have the local time stored with the file. The following list of items may be visible in the data header row, depending on which values are logged: LI-7700 Open Path CH Analyzer...
  • Page 90 Methane mole fraction ( mol/mol) µ CH4D Methane number density (mmol/m TEMP Temperature measured with the LI-7700 thermocouple (°C) PRESSURE Pressure measured near the optical path (kPa) RSSI Signal strength (Residual Signal Strength Indicator, 0-100%) DROPRATE Percentage of 1000Hz scans that were dropped at an output rate of 40 Hz (0-100%).

  • Page 91: Diagnostics Header

    Each value is an integer between 0 and 65535, which can indicate up to 16 diagnostics. The following guide and example can help interpret this diagnostic information. Table 4-3. Diagnostic codes output with the LI-7700 data record. Diagnostics Header Integer...
  • Page 92 Repeating the steps above, it is determined that three thermocouples were not at- tached or were dysfunctional, and the LI-7700 is connected to an LI-7550. In summary, if there is a diagnostic value of 17231, the instrument was in the midst of a cleaning cycle while heating the lower mirror.

  • Page 93: Status Columns

    Device present USBCAPACITY USB device capacity USBFREESPACE USB device free space A diagnostic value used in technical support OPTICSDELTA Temperature difference between air and upper mirror A checksum feature to check the integrity of data LI-7700 Open Path CH Analyzer...

  • Page 94: Making Flux Measurements With The Li-7700

    Important: Temperature measurements used in the methane flux calculations should always come from the sonic anemometer. There is a small thermocouple on the LI-7700 but it should not be used for flux measurements because its frequency response varies between 1 Hz and about 10 Hz, depending upon wind speed.

  • Page 95: Computing Fluxes

    Making Flux Measurements with the LI-7700 Important: Water vapor flux measurements are required to compute methane fluxes with the LI-7700. These data should be acquired with an LI-7500A, LI-7500, LI-7200, or other H O analyzer. Computing Fluxes Important: Use the uncorrected methane number density channel (CH4D, mmol/m for flux measurements.
  • Page 96 , and Water vapor broadening factor, dimensionless. α − 1 = 0.46 Specific to the is the foreign gas broadening coefficient for water vapor on α LI-7700. See page 6- methane, = 1.46 ∂ κ κ κ . Rate of change in κ...
  • Page 97 Making Flux Measurements with the LI-7700 Table 5-2. Variables used in Equation 5-2 and to compute values for A, B, and C. Numerical values given below are used in the example calculation. Variable Description Source correct methane flux computed = mg CH...

  • Page 98: Example Calculation

    Computing Fluxes Example Calculation We present the example in two steps. First, we compute A, B, and C using the individual factors shown in Table 5-2 to illustrate the magnitudes of all the factors entering into the calculation. In a second step we show a somewhat simpler approach. Full Computation In this example we calculate average CH flux for a one-hour period over a maize field...
  • Page 99 Making Flux Measurements with the LI-7700 For comparison, note that the raw uncorrected flux was -0.468 (-0.47) mg CH and the flux computed according to the traditional WPL equation, but not corrected for spectroscopic effects, was -0.11 mg CH LI-7700 Open Path CH...

  • Page 100: Simplified Computation

    Computing Fluxes Simplified Computation Now, as the second step, we note that the calculations can be simplified by tabulating κ κ two collections of coefficients: α and T . Table 5-6 gives a subset of values κ κ κ κ for α...

  • Page 101: Finding Multipliers

    , and T κ κ Low Resolution Look-up Tables (Tables 5-8, 5-9, and 5-10); Parametric Equations (Equations 5-3, 5-4, and 5-5); or High Resolution Digital Tables (provided with the LI-7700 software CD). Low Resolution Look-up Tables κ κ , α...
  • Page 102 Computing Fluxes κ Interpolate to find α κ κ =22.25 °C, first find the value for α With P = 98.6 kPa and at 22.25 °C and κ pressure of 95 kPa, which is ⎡ ⎤ 0.4102 − 0.4196 0.4196 + 22.25 −...
  • Page 103 Making Flux Measurements with the LI-7700 κ Interpolate to find κ With P = 98.6 kPa and =22.25 °C, first find the value at 22.25 °C and 95 kPa, which ⎡ ⎤ 0.3870 − 0.3459 0.3459 + 22.25 − 20 = 0.3551...

  • Page 104: Parametric Equations

    . Using the formulas, these values can be approximated with reasonably good κ precision. The formulas were derived empirically from high-resolution tables. They are presented in a Microsoft® Excel file on the LI-7700 Software CD. The file is called LI_7700_Flux_Multipliers and the formulas are under the “Parametric Equations” tab. Computing κ...
  • Page 105 Making Flux Measurements with the LI-7700 κ Computing α κ κ To compute α as a function of temperature and pressure, first compute κ = P 1 + 0.46x equivalent pressure, , then κ α = a × T + b ×...
  • Page 106 Computing Fluxes κ Computing κ κ To compute T as a function of temperature and pressure, first compute equivalent κ = P 1 + 0.46x pressure, , then κ = a × T + b × T + c × P + d ×...

  • Page 107: High Resolution Digital Tables

    Making Flux Measurements with the LI-7700 High Resolution Digital Tables The LI-7700 software CD includes tab delimited text files and a Microsoft® Excel file called “LI_7700_Flux_Multipliers.” These files contain high-resolution tables of κ κ κ α , and T , covering temperatures of -50 to 55 °C and pressures of 50 to κ...
  • Page 108 1 °C and 1 kPa increments over the range -50 to 55°C and 50 to 115 kPa (See Chapter 6 for details). This is a subset of the high-resolution table stored in the instrument and provided as a digital resource from LI-COR. The value at 22.25 °C and 98.6 kPa (equivalent pressure) was determined by linear interpolation.
  • Page 109 Making Flux Measurements with the LI-7700 ∂ κ κ Table 5-5. Rate of change of κ with temperature at constant Pe, . The derivatives are computed from Table 5- ∂T 3. The value at 22.25 °C and 98.6 kPa was determined by linear interpolation. Compute equivalent pressure, = P 1 + 0.46x...
  • Page 110 Computing Fluxes κ = P 1 + 0.46x . Compute equivalent pressure, P Table 5-7. Computed values for T , before entering the table. κ Equivalent Temperature (°C) Pressure (kPa) 22.25 0.3395 0.3437 0.3479 0.3520 0.3561 0.3603 0.3332 0.3374 0.3415 0.3457 0.3498 0.3540...
  • Page 111 Making Flux Measurements with the LI-7700 κ Table 5-9. Values for α from -30 °C to 50 °C and 50 kPa to 110 kPa. Values in this table can be κ = P 1 + 0.46x approximated with equation 5-5. Compute equivalent pressure, , before entering the table and interpolate between temperature and pressure values to find the value with reasonably good precision.

  • Page 112: Zero Flux Validation

    Zero Flux Validation As a test of performance of the LI-7700 and the procedures described above, LI-COR deployed the LI-7700 in an agricultural field near Lincoln, NE. This research site has a year-round history of chamber-based methane measurements, which show methane flux ranging from -0.12 to 0.13 mg m...

  • Page 113: References

    Making Flux Measurements with the LI-7700 Flux (with WPL and Spectroscopic Effects Corrections) Raw CH Flux -0.5 -1.0 Chamber Maximum -1.5 Chamber Minimum -2.0 -2.5 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Hour of the Day Figure 5-2.

  • Page 114: Theory And Equation Summary

    − I ΔI ≅ α Using Wavelength Modulation Spectroscopy (WMS), the LI-7700 laser scans across a single feature in the 2ν absorption band of methane near 1.6 microns with high resolution and at a high repetition rate. The wavelength is modulated at sub-MHz...

  • Page 115: Temperature Dependence Of Absorption Line Strength

    = ln 2 where k is the Boltzmann constant, m is molecular mass, and T is temperature (K). Pressure broadening is described by the Lorentzian lineshape: Δv v; Δv π v − v + Δv LI-7700 Open Path CH Analyzer...
  • Page 116 Absorption of Infrared Radiation by a Gas where is is Lorentzian half width and can be calculated using empirically Δv determined parameters from HITRAN database: ⎡ ⎤ ⎡ ⎤ Δv = γ T P , T ⎢ ⎥ ⎢ ⎥ ⎣...

  • Page 117: Wavelength Modulation Spectroscopy

    Because very strong amplitude modulation is also present at carrier frequency f, higher order harmonics are preferable for detecting a small absorption feature. The LI-7700 uses phase-sensitive demodulation by a digital lock-in amplifier at 2f to obtain a background-free signal with excellent noise rejection.

  • Page 118: Compensating For Temperature And Pressure Changes

    T is temperature (°C), and P is atmospheric pressure (kPa). Atmospheric pressure and air temperature are measured by the LI-7700 using an on-board pressure sensor and thermocouple, and are output with the data stream; however, because the LI-7700 temperature measurements are relatively slow, κ(T,P) is not applied to the CH...
  • Page 119 As described in the previous section, only the ρ channel (methane density, mmol m which is uncorrected for T and P, should be used for flux measurements. Temperature LI-7700 Open Path CH Analyzer...

  • Page 120: Compensating For Water Vapor: Equivalent Pressure, P

    α – 1, and x /P is water vapor mole fraction. For the LI-7700, a found experimentally to have a value of 1.46 (Figure 6-4), but this value may vary for other instruments depending upon the gas species, the absorption line or lines being measured, and the instrument design.
  • Page 121 P in κ (T,P ). The water broadening coefficient used here is specific to the LI-7700 but is consistent with water vapor broadening parameters extrapolated from Gharavi and Buckley (2005) over much higher temperatures and water vapor mole densities.

  • Page 122: Derivation Of Multipliers For Flux Measurements

    µ reported by the LI-7700 is compensated for pressure in real time and for temperature using a relatively slow thermocouple, but not water vapor, so it is not suitable for flux calculations. The methane mole fraction output can be used for calibration and diagnostic purposes but we do not recommend its use for flux calculations.
  • Page 123 δ T . If barometric pressure P were considered to vary its effect would enter the derivation here; but at constant P, and substituting primes for deltas, = α RT ρ '+ α R ρ 6-25 6-10 LI-7700 Open Path CH Analyzer...
  • Page 124 Derivation of Multipliers for Flux Measurements w ' ρ ' = κ w ' ρ ' + κ ρ w 'T ' + κ ρ α RT w ' ρ ' + α R ρ w 'T ' 6-26 Substituting RT = 1 −...
  • Page 125 κ ⎡ ⎤ α 1 + 1 − x 1 − x ⎢ ⎥ is the sensible heat multiplier. Both κ κ ⎣ ⎦ κ multipliers involve the term 1 − x α κ 6-12 LI-7700 Open Path CH Analyzer...
  • Page 126 Step-by-step instructions are given in Chapter 5 for applying these corrections. Software utilities and digital copies of the tables are also available from LI-COR. The last term in multiplier C is multiplied by the mole fraction of water vapor, which is often near 0.02.

  • Page 127: References

    Boundary Layer Meteorology, 121: 221-227. Webb E.K., G. Pearman, and R. Leuning. 1980. Correction of flux measurements for density effects due to heat and water vapor transfer, Quarterly Journal of the Royal Meteorological Society, 106: 85-100. 6-14 LI-7700 Open Path CH Analyzer...

  • Page 128: Advanced Operation

    After the software completes the zero operation choose either to apply the new calibration value or revert to the previous calibration value. If the application is closed or if the LI-7700 is powered off before a confirmation command is received the new calibration will not be applied.
  • Page 129 Use this only if you attempt to set the zero and span, but are unable to complete the procedure for some reason or another, or if you complete an attempted calibration, but prefer to use the factory zero and span settings. LI-7700 Open Path CH Analyzer...

  • Page 130: Diagnostics

    In the LI-7700, the laser scans a sealed vessel of methane along with the open path cavity. The results of the cavity scan (reference) and...

  • Page 131: Opening The Laser Temperature Control Dialog

    As the dialog indicates, there are two temperature parameters that may be manipulated. Laser Cooler temperature is the primary one and should be altered first. In order to change the value, the Line Lock setting must be changed from “Automatic” to “Manual”, as shown below. LI-7700 Open Path CH Analyzer...

  • Page 132: Manual Line Lock Example

    Diagnostics This will allow you to set the temperature manually. When you are changing the laser cooler temperature, watch the diagnostics page and see how the waveform changes as the temperature setting is increased or decreased. Manual Line Lock Example In this example, the automatic line lock was disabled and the laser temperature was manually driven from a value of 10.0 to 16.0.
  • Page 133 Advanced Operation LI-7700 Open Path CH Analyzer...

  • Page 134: Re-Enabling Automatic Line Lock

    Networking The LI-7700 supports IPv4 and IPv6. IPv4 is the first Internet Protocol to be widely used. It is nearly 20 years old and will be superseded by IPv6. IPv6 provides many advantages, one of which is that is allows for substantially more IP address. This will help accommodate the growing number of devices that are connected to the Internet.

  • Page 135: The Li-7700 Finder Application

    Upon launching the application, you will see a list of all LI-7700s and LI-7550s on your local network. When you select an LI-7700, you can select Watch LI-7700, or when you select an LI-7550 you can choose Config LI-7550. LI-7700 Open Path CH...
  • Page 136 The LI-7700 Finder Application Selecting Watch LI-7700 opens a variables window: This displays numerous parameters used by the LI-7700. Along the bottom of the window are nine buttons, which are described below: Click the Wave button: The window above shows the waveform. It is identical to the waveform displayed in the Diagnostic Page 1 tab on the Main View.
  • Page 137 “Rollback” in the Factory Settings dialog or restart the instrument to restore normal operation. Click the Laser Temp… button: The laser temperature control dialog is similar to the Laser Temperature control described above in the Manual Line Lock example (page 7-5). 7-10 LI-7700 Open Path CH Analyzer...
  • Page 138 Main View. Click the Factory… button: The window above is used to perform diagnostic checks. Do not change any settings in this window unless in consultation with LI-COR Biosciences technical support. Click the Heaters… button: Instruction Manual Version 2...
  • Page 139 Advanced Operation Provides access to mirror heater controls. Click the Clock… button: Here you can set the LI-7700 clock. 7-12 LI-7700 Open Path CH Analyzer...
  • Page 140 The LI-7700 Finder Application Click the Network… button: This window allows you to change the instrument name and network settings. Instruction Manual Version 2 7-13...

  • Page 141: Communications Grammar

    This section describes the protocol used by the LI-7700 to communicate via RS-232 and Ethernet for both configuration and data output purposes. Commands sent to the LI-7700 have a certain structure that must be followed, and data sent by the LI-7700 comes packaged in a particular way.

  • Page 142: Element Descriptions

    “or”. {bool} Boolean values, TRUE | FALSE. {float} Floating point values in decimal or exponential notation. {int} Integer {string} String Grammar A full LI-7700 XML file will resemble the following: <licor> <li7700> <ver>{string}</ver> <name>{string}</name> <serialnumber>{string}</serialnumber> <ipaddress>{string}</ipaddress> <output> <rate>{0|1|2|5|10|20|40}</rate> <waveforms>{true|false}</waveforms> <status>{true|false}</status>...
  • Page 143 <aux7>{true|false}</aux7> <aux8>{true|false}</aux8> <auxtc1>{true|false}</auxtc1> <auxtc2>{true|false}</auxtc2> <auxtc3>{true|false}</auxtc3> <chk>{true|false}</chk> <date>{true|false}</date> <time>{true|false}</time> </data> <status>{same_file|separate_file|off}</status> <split>{0|15|30|60|90|120|180|240|1440}</split> </usb> </box> <cfg> <temprange>{low|high}</temprange> <clock> <time>{string:00:00:00}</time> <date>{string:1970-01-01}</date> <zone>{enter your time zone}</zone> <ptp>{auto|slaveonly|preferred}</ptp> </clock> <network> <name>{string:ch4-xxxx}</name> <configuration>{auto|manual}</configuration> <ipaddress>{int.int.int.int}</ipaddress> <netmask>{int.int.int.int}</netmask> <gateway>{int.int.int.int}</gateway> </network> <aux1> <type>{poly|steinhart|linear-rt}</type> <a0>{float:0}</a0> 7-16 LI-7700 Open Path CH Analyzer...
  • Page 144 Communications Grammar <a1>{float:1}</a1> <a2>{float:0}</a2> <a3>{float:0}</a3> </aux1> <aux2> <type>{poly|steinhart|linear-rt}</type> <a0>{float:0}</a0> <a1>{float:1}</a1> <a2>{float:0}</a2> <a3>{float:0}</a3> </aux2> <aux3> <type>{poly|steinhart|linear-rt}</type> <a0>{float:0}</a0> <a1>{float:1}</a1> <a2>{float:0}</a2> <a3>{float:0}</a3> </aux3> <aux4> <type>{poly|steinhart|linear-rt}</type> <a0>{float:0}</a0> <a1>{float:1}</a1> <a2>{float:0}</a2> <a3>{float:0}</a3> </aux4> <aux5> <type>{poly|steinhart|linear-rt}</type> <a0>{float:0}</a0> <a1>{float:1}</a1> <a2>{float:0}</a2> <a3>{float:0}</a3> </aux5> <aux6> <type>{poly|steinhart|linear-rt}</type> <a0>{float:0}</a0> <a1>{float:1}</a1> <a2>{float:0}</a2> <a3>{float:0}</a3> </aux6>...
  • Page 145 <low>{float:0}</low> <high>{float:0}</high> </dac3> <dac4> <set>{float:0;-5...5}</set> <src>{set|ch4d|ch4|temp|pressure|rssi|droprate|aux1|aux2|aux3|aux4|aux5|aux6|aux7|aux8 |auxtc1|auxtc2|auxtc3}</src> <low>{float:0}</low> <high>{float:0}</high> </dac4> <dac5> <set>{float:0;-5...5}</set> <src>{set|ch4d|ch4|temp|pressure|rssi|droprate|aux1|aux2|aux3|aux4|aux5|aux6|aux7|aux8 |auxtc1|auxtc2|auxtc3}</src> <low>{float:0}</low> <high>{float:0}</high> </dac5> <dac6> <set>{float:0;-5...5}</set> <src>{set|ch4d|ch4|temp|pressure|rssi|droprate|aux1|aux2|aux3|aux4|aux5|aux6|aux7|aux8 |auxtc1|auxtc2|auxtc3}</src> <low>{float:0}</low> <high>{float:0}</high> </dac6> <heater> <top> <heaterpower>{integer:100;0...100}</heaterpower> <control>{auto|on|off}</control> <ontime>{HH:MM}</ontime> <offtime>{HH:MM}</offtime> <deltat>{float:0;-5...5}</deltat> </top> <bottom> <heaterpower>{integer:100;0...100}</heaterpower> 7-18 LI-7700 Open Path CH Analyzer...
  • Page 146 Communications Grammar <control>{auto|on|off}</control> <ontime>{HH:MM}</ontime> <offtime>{HH:MM}</offtime> <signalstrengthlevel>{integer:40;0...100}</signalstrengthlevel> </bottom> </heater> <linelock> <lasercooler> <control>{auto|manual|daccount}</control> <temp>{float:25;0...50}</temp> <daccount>{integer:0;0...65535}</daccount> </lasercooler> <laserblock> <control>{off|on|daccount}</control> <temp>{float:22;0...50}</temp> <daccount>{integer:0;0...65535}</daccount> </laserblock> </linelock> <spinmirror> <control>{auto|on|off}</control> <ontime>{HH:MM}</ontime> <offtime>{HH:MM}</offtime> <duration>{integer:30;0...300}</duration> <repeatinterval>{HH:MM}</repeatinterval> <signalstrengthlevel>{integer:40;0...100}</signalstrengthlevel> </spinmirror> <sdmaddress>{integer:0;0...15}</sdmaddress> </cfg> <cal> <ch4zero>{float:0}</ch4zero> <ch4span>{float:1}</ch4span> <ch4spanconc>{float:2}</ch4spanconc> <ch4lastzero>{YYYY-MM-DD HH:MM:SS.SS}</ch4lastzero> <ch4lastspan>{YYYY-MM-DD HH:MM:SS.SS}</ch4lastspan> <history> <record> <time>{YYYY-MM-DD HH:MM:SS.SS}</time>...
  • Page 147 </cal> <cmd> <poll>{true|false}</poll> <ch4zero>{true|false}</ch4zero> <ch4span>{true|false}</ch4span> <calcommit>{true|false}</calcommit> <calrollback>{true|false}</calrollback> <calabort>{true|false}</calabort> <logusbstart>{true|false}</logusbstart> <logusbstop>{true|false}</logusbstop> <reboot>{true|false}</reboot> <polltest>{true|false}</polltest> <linelock>{true|false}</linelock> </cmd> <cpld> <ver>{string}</ver> <motor> <control>{integer:0}</control> <desired_pos>{integer:0}</desired_pos> <actual_pos>{integer:0}</actual_pos> </motor> </cpld> <factory> <serialnumber>{string:ch4-XXXX}</serialnumber> <lasermoddepth>{integer:7000}</lasermoddepth> <laserstarttemp>{float:22;0...50}</laserstarttemp> <blockstarttemp>{float:30;0...50}</blockstarttemp> <blockstarttemplowrange>{float:5;0...50}</blockstarttemplowrange> <rssidropthresh>{float:1;0...100}</rssidropthresh> <pzero>{float:0}</pzero> <pspan>{float:1}</pspan> <samplegain>{integer:0;0...2147483647}</samplegain> <refgain>{integer:0;0...2147483647}</refgain> <mirrorpos>{integer:0;0...1023}</mirrorpos> 7-20 LI-7700 Open Path CH Analyzer...

  • Page 148: Configuration File Grammar

    Communications Grammar <offset1>{integer:0;0...65535}</offset1> <delta1>{integer:0;0...65535}</delta1> <offset2>{integer:0;0...65535}</offset2> <delta2>{integer:0;0...65535}</delta2> <dither>{integer:0;0...65535}</dither> <sampledcoffset>{integer:0;0...65535}</sampledcoffset> <sampleacoffset>{integer:0;-32768...32767}</sampleacoffset> <sampleopticaloffset>{integer:0;-32768...32767}</sampleopticaloffset> <cmd> <commit>{true|false}</commit> <rollback>{true|false}</rollback> </cmd> </factory> </li7700> </licor> Configuration File Grammar Configuration files are constructed when you save an instrument configuration (see page 2-19). You can view or edit the configuration grammar by opening the configuration file in an HTML editor or text editor.
  • Page 149 <a3>0</a3> </aux7> <aux8> <type>poly</type> <a0>0</a0> <a1>1</a1> <a2>0</a2> <a3>0</a3> </aux8> <heater> <top> <heaterpower>25</heaterpower> <control>off</control> <deltat>5</deltat> <ontime>03:00</ontime> <offtime>22:00</offtime> </top> <bottom> <heaterpower>25</heaterpower> <control>off</control> <signalstrengthlevel>35</signalstrengthlevel> <ontime>01:00</ontime> <offtime>22:00</offtime> </bottom> </heater> <linelock> <lasercooler> <control>auto</control> <temp>16.3</temp> </lasercooler> <laserblock> <control>on</control> <temp>30</temp> </laserblock> 7-22 LI-7700 Open Path CH Analyzer...
  • Page 150 Communications Grammar </linelock> <spinmirror> <control>off</control> <ontime>00:00</ontime> <offtime>00:00</offtime> <duration>70</duration> <repeatinterval>00:03</repeatinterval> <signalstrengthlevel>100</signalstrengthlevel> </spinmirror> <dac1> <set>0</set> <src>ch4</src> <low>0</low> <high>5</high> </dac1> <dac2> <set>0</set> <src>temp</src> <low>0</low> <high>0</high> </dac2> <dac3> <set>0</set> <src>pressure</src> <low>0</low> <high>0</high> </dac3> <dac4> <set>0</set> <src>rssi</src> <low>0</low> <high>0</high> </dac4> <dac5> <set>0</set> <src>rssi</src> <low>0</low> <high>0</high> </dac5>...

  • Page 151: Sending Commands

    This would change the mirror heater settings to whichever values you specify. To set the temperature range to the 0C...50C range: <licor><li7700><cfg><temprange>high</temprange></cfg></li7700></licor> To set the temperature range to the -25C...25C range: <licor><li7700><cfg><temprange>low</temprange></cfg></li7700></licor> To force the instrument to re-linelock: <licor><li7700><cmd><linelock>true</linelock></cmd></li7700></licor> 7-24 LI-7700 Open Path CH Analyzer...

  • Page 152: Appendices

    Appendices Appendix A. Specifications LI-7700 Open Path CH Analyzer Calibration Range: 0-40 ppm @ 25 °C 0-25 ppm @ -25 °C 0-50 ppm total Bandwidth: 0, 1, 2, 5, 10, or 20 Hz Linearity: Within 1% of reading across full calibration range...

  • Page 153: 7700-101 Washer Assembly

    5 m (16.4 ft) 7550-101 Auxiliary Sensor Interface (optional) 11.5 × 6.5 × 4.2 cm (4.5 × 2.6 × 1.7 in.) Size: Weight: 0.39 kg (0.85 lbs) including mounting bracket Cable Length: 0.75 m (2.5 ft) LI-7700 Open Path CH Analyzer...

  • Page 154: Power Requirements Summary

    Appendix A - Specifications Power Requirements Summary The LI-7700 uses about 8 watts during normal operation, but when accessories and mirror heaters are used, power requirements could be up to or greater than 41 watts. Table 8-1 can be used to determine how much power is required in a variety of configurations: Table 8-1.

  • Page 155: Appendix B. Maintenance

    Appendix B. Maintenance Changing the Internal Desiccant Bottle There is one internal desiccant bottle in the LI-7700. The desiccant cap is above the cir- cular plug located on the bottom of the top dome of the analyzer between two spars (see below).
  • Page 156 Appendix B - Maintenance Remove the seal from the top of the replacement desiccant bottle. Insert the bottle cap first and replace the cover. Press firmly to secure the desiccant cover and replace the setscrew. Over time, the “Optics RH:” should approach zero. This may take several minutes to several hours, depending on the humidity level.

  • Page 157: Changing The Thermocouple

    The fine wire thermocouple should be replaced if the wire is broken or if it reads incor- rectly. One spare thermocouple is included in the spares kit, and others can be purchased from LI-COR Biosciences (p/n 9977-038). To replace the thermocouple: Disconnect the power supply to turn the LI-7700 off.

  • Page 158: Changing The Li-7700 Fuse

    If the LI-7700 fails to power up when connected to a suitable power supply, check to see if the fuse has blown. The LI-7700 fuse is enclosed within the knurled fuse cover on the connection panel. One extra 250V type F 5.0 Amp fuse (p/n 438-09800) is included in the spares kit.

  • Page 159: Appendix C. Troubleshooting

    Power supply inadequate – be sure the power supply is 10.5 to 30 VCD, 3 Amps. Temperature readings are unreasonable: Thermocouple damaged – replace the optical path thermocouple. LI-7700 not visible on the network: Check the Ethernet data cable connections. Pressure measurements noisy: The mirror washer causes perturbations in the pressure measurement due to the proximity of the pressure sensor to the lower mirror.
  • Page 160 Check the zero and span using the procedure described on page 7-1. If these do not work, contact LI-COR Biosciences. Instrument does not keep time when disconnected from power supply: The internal battery needs to be replaced. Contact LI-COR for details. Instruction Manual Version 2...

  • Page 162: Appendix D. Suppliers

    The company names and contact information given below are the most current we have at the time of this printing. In some cases, the information may change without notice. Chemical Sources Desiccant LI-COR Part Number Scrub Bottle Kit (1 pre-charged scrub bottle) 7700-950...

  • Page 163: Calibration Gases

    Plumsteadville, PA 18949 Phone: 800-217-2688 FAX: 215-766-2476 solutions.center@airliquide.com www.alspecialtygases.com www.scottgas.com Check for local distributors Canada Air Liquide Canada Inc. 1250 Rene-Levesque Boulevard West Suite 1700 Montreal, PQ H38 5E6 Phone: 800-217-2688 FAX: 514-846-7700 Email: info.alc@airliquide.com www.specialtygas.ca 8-12 LI-7700 Open Path CH Analyzer...

  • Page 164: Turck® Cables

    PKGV4M/S90 * refers to cable length † when ordering a power cable from LI-COR, request p/n 9975-030. Power cables pro- vided by Turck may have bare leads; the brown and white leads connect to the negative terminal, and the blue and black connect to the positive terminal.

  • Page 165: Industrial Rated Usb Flash Drives

    Nurail Metropolitan Pipe & Supply Co. 303 Binney St. Cambridge, MA 02142 USA Phone: 1-800-638-7473 Fax: 617-354-3869 www.nurail.com Diamond Aluminum Company 119 E. Galbraith Road Cincinnati, OH 45216 Phone: 513-821-1080 Fax: 513-821-0121 info@diamond-aluminum.com www.diamond-aluminum.com 8-14 LI-7700 Open Path CH Analyzer...

  • Page 166: Warranty

    LI-COR, Inc.'s examination discloses to have been defective in material or work- manship without charge and only under the following conditions, which are: 1. 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 167 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.

  • Page 168: Index

    Index Cancel button, 2-4 charts, 2-4 clock. see time About LI-7700 PC Application icon, 2-2 O Analyzer, using the LI-7700 with, Analog Input/Output Cable, 3-3 analog inputs configuration file Analyzer Interface Unit creating, 2-19 implementing, 2-19 Configure Auxiliary Inputs icon, 2-25, 3-15...
  • Page 169 7-4 factory reset, 7-2 LI-7200. see CO O Analyzer files. see data LI-7500A. see CO O Analyzer Finder Application, LI-7700, 7-8 LI-7550. see Analyzer Interface Unit flash drive. See USB line broadening mechanisms, 6-2 flux computation line lock about, 5-2...
  • Page 170 Analyzer Interface Unit, 3-5 Spin Motor Control polynomials, 2-25 about, 2-12 power cable examples, 2-14 LI-7550 Analyzer Interface Unit, 3-2 indicator, 2-3 LI-7700 Methane Analyzer, 1-3 splitting files, 2-7 power connection, 1-9 status columns power on header, 4-6 LI-7550, 3-6 logging, 2-7...
  • Page 171 about, 3-14 cleaning solution, 1-12 ejecting, 3-13 waveforms, 7-3 formatting, 3-14 Waveforms icon, 2-2 storage capacity, 3-14 wavelength modulation spectroscopy, 6-4 suppliers, 8-14 zero. see calibration vibrations, 2-27 zero flux, 5-19 washer about, 1-4...
  • Page 172 Measuring Change in a Changing World ® LI-COR, Inc. • Environmental 4647 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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