LI-COR LI-820 Instruction Manual
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LI-COR LI-820 Instruction Manual

Co2 analyzer
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Summary of Contents for LI-COR LI-820

  • Page 1 Instruction Manual...
  • Page 2 LI-820 Analyzer Instruction Manual...
  • Page 3 CE Marking: This product (model number LI-820) is a CE-marked product. For conformity information, contact LI-COR support at http://www.licor.com/env/support. Outside of the U.S., contact your local sales office or distributor.
  • Page 4 SJ/T 11363-2006 Industry Standard. X: this component does contain this hazardous substance above the maximum concentration values in homogeneous materials specified in the SJ/T 11363-2006 Industry Standard (Company can explain the technical reasons for the "X") 分析仪 LI-820 CO 有毒有害物质或元素 多溴二苯醚 部件名称...
  • Page 5 The information contained in this document is subject to change without notice. LI-COR MAKES NO WARRANTY OF ANY KIND WITH REGARD TO THIS MATERIAL, INCLUDING, BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. LI-COR shall not be liable for errors contained herein or for incidental or consequential damages in connection with the furnishing, performance, or use of this material.

  • Page 6: Table Of Contents

    Table of Contents Section 1. General Description What’s What ......................................Features ........................................ Precautions ......................................Getting Started Tutorial..................................Section 2. Power On Power On......................................Low Battery Indicator..................................Alarms ........................................Section 3. Operation Installing the PC Communications Software on Your Computer ....................Setting the Communication Parameters .............................
  • Page 7 Diagnostics Window .................................... 3-17 Logging Data ......................................3-18 Calibration Window - Setting the Zero and Span ..........................3-22 Advanced Calibration (Manual Tab)............................3-23 Two Point Span (Advanced Tab) ..............................3-25 Connecting the LI-820 to the LI-1400 Data Logger .......................... 3-28...
  • Page 8 Two Point Scanning (Set S and S ) ..............................4-13 Section 5. Maintenance Cleaning the Optical Bench ................................Changing the Fuse ....................................Storing the LI-820....................................Appendix A. Specifications Appendix B. Pin Assignments Appendix C. List of Suppliers Appendix D. Configuration Grammar Warranty...

  • Page 9: Section 1. General Description

    General Description What's What This procedure should be followed if you have just taken delivery of your LI-820. Check the packing list to verify that you have received everything that was ordered and that you have also received the following items: RS-232 Cable - (Part #392-04993), used to connect the LI-820 to your computer.
  • Page 10 Standard Spare Parts Kit (9980-012) - This kit contains replacement parts for your LI-820. As you become familiar with the analyzer you will learn which items to keep close at hand and which items can be stored away. Some of the items in the spare parts...

  • Page 11: Features

    Features The LI-820 is an economical high performance, non-dispersive infrared gas analyzer designed to be used for a wide variety of applications. Some of the LI-820's important features include: The 14 cm (5.5") optical bench is used to measure CO concentrations over a range of 0- 20000 ppm.

  • Page 12: Getting Started Tutorial

    Install the 820-500 PC Communications Software. This software is used to set the zero and span of the LI-820 and to set up data communication and data transfer parameters. Installation instructions can be found in Section 3, Installing the Software on Your Computer.
  • Page 13 Determine your jumper settings for high and low alarm output, if required. There are 2 jumpers inside the LI-820 case (on the main circuit board) which toggle the high and low alarm output between 0-5V (TTL levels) and an open drain condition (see Section 2, Alarms).
  • Page 14 Connect the RS-232 cable. Connect one end of the serial cable to the 9-pin Serial I/O port on the LI-820 front panel, and the other end to a serial port on your computer. If you want to interface to a device with a 25- pin serial port, a 9-pin to 25-pin adapter must be used;...
  • Page 15 0.25 and 1.0 liters per minute. LI-COR offers a Diaphragm Pump under part number 286-04198 that is suitable for use with the LI-820. One pump plumbing option is shown below.
  • Page 16 Quick Connect ‘Y’ NOTE: More information about plumbing options and parts available from LI-COR can be found in Application Note #IRG4-105, entitled ‘Air Pumps and Accessories for LI-COR Gas Analyzers - Suggested Parts and Vendors’, which can be down- loaded at: https://www.licor.com/documents/dmhq6ow23w2qgy3dsb8v...
  • Page 17 FLOW IN IMPORTANT: Always install the external air filter before operating the LI-820. Insert filter into the input airstream before it enters the LI-820. Failure to do this will lead to contamination of the optical path. There are some quick connect fittings in the spare parts kit that can be used on either side of the Balston filter to aid in changing the filter out.
  • Page 18 Click on the program icon to start the 820-500 program. The 820-500 Main window appears. Select from the File menu. Choose the serial port to which the LI-820 is connected, Connect and the data output interval. Select the COM port and the data output interval, if desired, and click the button.
  • Page 19 Section 1 Configure the analyzer. Select from the View menu. The Settings window appears. Choose a value for Settings signal averaging (the Filter field), between 0 and 20 seconds. Set values for high and low alarms and corresponding dead bands, if desired. See Section 2 for a complete description of the alarms.
  • Page 20 Section 1 Set up the logging parameters. Select from the Logging menu. Choose the File Headings to be output with the data, Options the values to be logged, the field delimiter, and log frequency. Click . Choose from Start the Logging menu. Enter a file name for the data file. Click Save Set up the charting parameters, if desired.

  • Page 21: Section 2. Power On

    Power On Power On The LI-820 can be connected to a constant source of AC power using a transformer that provides 12-30VDC (12W minimum) to the LI-820. If the LI-820 is powered On with a battery below 10.5 volts, the analyzer will not power up, and the Low Battery LED on the top panel will illuminate.

  • Page 22: Alarms

    Section 2 Alarms The LI-820 is equipped with high and low alarms, which can be configured as open drain (open collector) or 0-5V output (TTL levels) using jumpers on the main PC board (Figure 2- 1). Figure 2-2 shows the position of the jumpers for each of the two alarm conditions.
  • Page 23 Section 2 Alarm Jumpers Figure 2-1. Location of alarm jumpers LK1 and LK2. Power On...
  • Page 24 Section 2 Open Drain TTL (Digital, 0-5V) Figure 2-2. Position of jumpers for open drain and TTL (0-5V) output. Power On...
  • Page 25 Section 2 In addition, a "dead band" value can be set in software for both high and low alarms. To understand how the alarms and dead band values work, look at the diagram below. High Alarm activated 1000 High Alarm = 1000 Dead Band = 100 ppm High Alarm deactivated Low Alarm...
  • Page 26 Filter in Section 3) can help reduce fluctuations in readings. Alarm LEDs can be viewed on the top panel of the LI-820. Terminals 3 and 5 on the terminal strip are connected to the High and Low alarms, respectively. This is useful in cases where...
  • Page 27 Section 2 Air Inlet LI-820 1 2 3 Mains 120VAC Exhaust Input 3 - 30V 12VDC Output A list of suppliers of electronic relay switches can be found in Appendix C. NOTE: Consult your local electrical codes before wiring, and/or have a professional electrician wire your application.

  • Page 28: Section 3. Operation

    Operation Installing the PC Communications Software on Your Computer The 820-500 software is shipped on CD. It requires that your computer have a USB or RS- 232 serial (COM) interface, and Windows® XP/Vista. An installation menu starts when you insert the CD into your CD-ROM drive. Select Install Software from the menu and follow the instructions.

  • Page 29: Setting The Communication Parameters

    The serial cable included has 9-pin connectors on both ends; either end plugs into the 9-pin connector (Serial I/O) on the front panel of the LI-820. Use this cable to interface with your computer's 9-pin serial port. If you want to interface to a computer with a 25-pin serial port, a 9-pin to 25-pin adapter must be used.

  • Page 30: Initial Setup

    Section 3 The 820-500 PC Communication Software that comes with the LI-820 is used to transfer data and setup files between the analyzer and the PC. Initial Setup Click on the LI-820 program icon to start the program. The LI-820 Main Window appears.
  • Page 31 Section 3 Operation...
  • Page 32 (ppm), as well as the status of various LI- 820 parameters. There are also three menus used to configure the LI-820, perform zero and span calibrations, and set up the parameters for recording data. The LI-820 parameters in this...

  • Page 33: Using The Toolbar

    20 seconds. Path Length Shows the size of the optical bench installed in the LI-820, either 5.5 inches (14 cm), or 2 inches (5 cm). The 2 inch bench is no longer available, but may be present in older instruments.

  • Page 34: Settings Window - Setting Operational Parameters

    Section 3 Settings Window - Setting Operational Parameters The Settings window contains parameters related to initial setup of the LI-820, including signal filtering, high and low alarm setup, heater and pressure compensation options, and DAC output sources. Choose Settings from the View menu (or click on the toolbar icon) to...
  • Page 35 Section 3 The heater should DAC output be enabled to range. Choose maintain the source to be optical bench at a output to DAC 1 constant 50 °C. (terminal strip Pressure connector #9), compensation is and/or DAC 2 an optional (terminal strip parameter.

  • Page 36: Options

    Section 3 Options Enable Heater The Heater should be enabled to maintain the optical bench at a constant 50 °C. Pressure Compensation Enable the Pressure Compensation check box to automatically correct gas concentration values for changes in cell pressure. In most cases this should be turned on; disabling this feature means that no pressure correction is desired in the gas concentration calculations, which can lead to erroneous measurements.
  • Page 37 Voltage output is measured by attaching the positive lead from the logging device to terminal 9 (V Out 1), or terminal 7 (V Out 2) on the LI-820 terminal strip. Connect the negative lead to position 10, (GND), or position 8.

  • Page 38: Converting Voltage Output To Cell Temperature

    Section 3 2000 = 1160 ppm. Example 2: The DAC output range selected is 0-5V (V ), the zero CO value entered is 1000 ppm (X ), the full scale CO value entered is 2000 ppm (X ), and the measured output voltage (V) is 2.9V.

  • Page 39: Converting Voltage Output To Cell Pressure

    Section 3 Converting Voltage Output to Cell Pressure Cell pressure can be calculated from the DAC output voltage as follows: essure kPa − where V is the measured voltage, X is the full scale value for cell pressure output (entered in the Settings Window as the 2.5 or 5V value, up to 115 kPa), X is the zero value entered, and is the full scale DAC output voltage selected (5V or 2.5V).

  • Page 40: Using The Terminal Strip

    = 1531.25 ppm. Using the Terminal Strip The terminal strip is located on the front panel of the LI-820. To connect the wires, insert the bare wire end into the appropriate terminal and tighten the screw above that terminal using the small flat head screwdriver in the spare parts kit.
  • Page 41 Section 3 The terminal positions are as follows, reading left to right: Terminal Label Description 12-30 VDC Voltage In, 12-30 VDC Ground High Alarm High Alarm Ground Low Alarm Low Alarm Ground V OUT 2 Voltage output channel 2 Ground V OUT 1 Voltage output channel 1 Ground...

  • Page 42: Charting Window

    Section 3 Charting Window Select Charting from the View menu to open the Charting window (below). This is the window in which you can set up the parameters for plotting your data. Operation 3-15...
  • Page 43 Section 3 X-Axis Max Sets the maximum value for the X axis (Time). The units for the X axis can be seconds or minutes. Y-Axis Max/Min Sets the maximum and minimum values for the Y axis (CO Press to send the current chart to your printer. Press to save the chart Print Chart Save Chart...

  • Page 44: Diagnostics Window

    Section 3 Diagnostics Window Select Diagnostics from the View menu to open the Diagnostics window (below). This window displays the current LI-820 internal software version number, the input voltage, and raw absorption value. Operation 3-17...

  • Page 45: Logging Data

    Section 3 Logging Data Start Logging Opens the Log File Destination dialog, where you enter a file name for the data file. The file extension .txt is added automatically. 3-18 Operation...
  • Page 46 Section 3 Stop Logging Stops data logging. Pause Logging Pauses logging of data until is chosen from the Logging menu again, or the Start button Start on the toolbar is pressed. Options Opens the Logging Options window, where you can configure the data output options. Operation 3-19...
  • Page 47 Section 3 3-20 Operation...
  • Page 48 Section 3 As configured above, the data output would appear similar to that shown below. File Headings Log Values System Cell Cell Temp. Pres. Time (1s log rate) Operation 3-21...

  • Page 49: Calibration Window - Setting The Zero And Span

    Section 3 Calibration Window - Setting the Zero and Span Select Calibration from the View menu to open the Calibration window. This is the area in which you set the zero and span of the LI-820. 3-22 Operation...

  • Page 50: Advanced Calibration (Manual Tab)

    Section 3 The calibration window shows the date and time at which the LI-820 was last zeroed and/or spanned. When spanning the instrument, you can enter the value of your span gas in the “Span gas concentration (ppm)” field. The Manual and Advanced tabs offer additional calibration options, discussed below under Two Point Span.
  • Page 51 Section 3 3-24 Operation...

  • Page 52: Two Point Span (Advanced Tab)

    If your LI-820 is exhibiting erratic behavior such as no response to CO , or erratic readings, check the span offset and span slope values. As an example, if the span is inadvertently set at...
  • Page 53 Section 3 The two point span function sets the span zero and span slope parameters. The two gas concentrations used to do this should be fairly well separated. One gas concentration should 3-26 Operation...
  • Page 54 Section 3 be fairly low – 600 ppm or less. The second gas concentration should be fairly high, and ideally, close to the upper range of concentration that you are interested in (e.g. 1500, 3000, 10000, etc.). If you are interested in a narrow range of concentrations, such as 300 to 500 ppm, then we do not recommend using 300 and 500 for a two point span;...

  • Page 55: Connecting The Li-820 To The Li-1400 Datalogger

    Section 3 Connecting the LI-820 to the LI-1400 Datalogger The following example shows how you can connect the LI-820 to a datalogging device such as the LI-COR Model LI-1400 DataLogger to collect analog data and convert to meaningful values. The CO concentration is calculated from the DAC output voltage as follows: −...
  • Page 56 Table 3- 1 lists some examples of values for this multiplier; simply choose the DAC output range in the second row, and then select the LI-820 CO range in the first column (the full scale value minus the zero value); follow across to find the appropriate multiplier. Note that this table assumes that the zero value (X ) is zero;...
  • Page 57 The following example shows how you can set up the LI-1400 Data Logger to collect raw voltage output from the LI-820 and convert to CO values. Set the voltage output of the LI-820 for 2.5V output as described in Section 3, Analog Output. In the LI-1400, configure V1 channel as General for CO Enter a description, such as CO2.
  • Page 58 Section 3 Set Oper(ator) = none. Enter a Label such as ppm for the units. Set Average=1 sec or as desired. CO will now be displayed on channel V1. To log CO automatically, follow the remaining steps: Set Log Routine to the desired log routine. Set Calc=Mean.

  • Page 59: Section 4. Theory Of Operation

    Theory of Operation System Overview The LI-820 CO Gas Analyzer is an absolute, non-dispersive, infrared (NDIR) gas analyzer based upon a single path, dual wavelength, infrared detection system. The CO measurement is a function of the absorption of IR energy as it travels through the optical path.

  • Page 60: Optical Bench System

    Analog signals are available through a terminal block for collection by a data logger or similar means. Optical Bench System The LI-820 CO Gas Analyzer optical path is a thermostatically controlled IR detection system. The optical bench operation is based upon a broad band IR source and two pyroelectric detectors.
  • Page 61 Parabolic Reflector Gold Plated Filters 3.95 & 4.26 μm Optical Path Detectors Source Broad Band IR Source Thermistor Thermistor Gas Outlet Gas Inlet Heating Element Heating Element Ribbon Cable Connector Figure 4-1. Schematic diagram of LI-820 optical bench. Theory of Operation...
  • Page 62 Section 4 The optical bench has a thermostat that maintains a constant operating temperature of 50 °C. A feedback loop is used to regulate the optical bench temperature. As shown in Figure 4-1, two thermistors, located in the source and detector housings, measure the present temperature. The thermistors are monitored as part of the control loop to determine corrections necessary in the thermal balance.

  • Page 63: Equation Summary

    This achieves the mechanical isolation desired for the optical bench. Equation Summary Measuring CO Absorptance absorptance is measured by the LI-820 by comparing the output of two detectors; one (W) filtered to a CO absorption band, and the other (W ) filtered to a non-absorption band. ⎛...
  • Page 64 ⎜ ⎟ ⎜ ⎟ ⎝ ⎠ ⎝ ⎠ The absorptance that is reported by the LI-820 is pressure corrected. Where g ,P) is an empirically-determined pressure correction function (Figure 4-2). ⎛ ⎞ for P < P ⎜ ⎟ ⎜ ⎟...
  • Page 65 Section 4 ⎛ ⎞ − ⎜ ⎟ − α ⎝ ⎠ − , whichever is > 1. The remaining coefficients are = 1.10158 = -6.12178 = -0.266278, = 3.69895, = 0.49609938 Theory of Operation...
  • Page 66 Section 4 α = 0 α = 0.05 α = 0.10 α = 0.15 α = 0.20 α P , α = 0.25 α = 0.30 Figure 4-2. The pressure correction function for CO . For comparison, the typical correction method for focused-optics IRGAs, such as the LI-6262, is also shown (P /P line).

  • Page 67: Computing Co Mole Fraction

    −1 α This relation, suggested to LI-COR by Agu Laisk (Research Professor of Estonian Acad. Sci., University of Tartu, Estonia), fits measurements of mole fraction and absorptance very well over a wide range of CO concentrations with only four parameters.
  • Page 68 Section 4 = 0.3989974 = 5897.2804 = 0.097101982 = 596.49981 The b parameter in the pressure correction equation (Equation 6) comes from the asymptote of this relation, = 0.49609938 4-10 Theory of Operation...

  • Page 69: Zeroing (Set Z)

    4-11 D = a Zeroing (Set Z) Zeroing the LI-820 consists of flowing CO -free air through the cell, and sending the zero command to the instrument. When it receives this command, it averages readings of W and for about 30 seconds, then computes Z such that...

  • Page 70: Single Point Scanning (Set S )

    Section 4 Single Point Spanning (Set S To set the span, flow a known CO concentration through the cell, and send the span command to the instrument. When it receives this command, it averages readings of W and for 30 seconds, and computes α...

  • Page 71: Two Point Scanning

    Section 4 This is done by iterating Equation 4-15, starting with , until the value of stops changing. (If the pressure correction is off, then no iteration is needed). is computed from α − α α 4-16 Two Point Spanning (Set S and S The two point span will not normally be required (after having been done initially at the factory), unless the source or detector has been changed.
  • Page 72 Section 4 Set Span 2 Readings are averaged for 30 seconds to compute α α = − 4-18 Equations 4-14 and 4-15 are performed, and the value retained as a . The S comes from α α − α α α...

  • Page 73: Section 5. Maintenance

    Follow these steps to clean the optical bench: Turn the LI-820 off. Remove the six screws on the LI-820 top panel and remove the cover. Note that these screws are not molded into the case and may fall out.
  • Page 74 Section 5 Detector Source Optical Bench Hose Barb Ribbon Cable Bev-a-line Tubing Connector Air In Air Out There are four screws on the source and detector circuit boards that must be removed. Remove the four screws in the corners of the boards, as shown below (they are slightly larger than the other four screws).
  • Page 75 Section 5 Remove these 4 screws The source and detector housings (with attached circuit boards) can now be removed. The bench will appear as shown below. It is a good practice to replace the O-rings when cleaning or replacing the optical path. Top View End View O-ring...
  • Page 76 Note that the orientation of the cylinder is not important; either end can be inserted into the source or detector housing. Re-assemble the LI-820 case. Make sure that the foam insulation on the inside top cover is positioned over the optical bench; it is required for thermal stability.

  • Page 77: Changing The Fuse

    To check the fuse, remove the six screws on the top of the LI-820. The fuse is located on the main circuit board, near the Flow In port, as shown in Figure 2-1. Replacement fuses (part #439-03952, in the spares kit) plug into the fuse holder;...
  • Page 78 Section 5 heaters on) for several hours to several days. If the instrument has not fully recovered after several days, you may need to disassemble the optical bench and heat the detector in an oven at 65 °C (150 °F) for several hours. Reassemble the instrument and check the measurements. Maintenance...

  • Page 79: Appendix A. Specifications

    Specifications* Measurement Range: 0 – 20000 ppm Measurement Principle: Non-Dispersive Infrared Accuracy: Measurement range 0 - 20000 ppm: <3% of reading Zero Drift: < .15 ppm/°C Span Drift at 370 ppm: <0.03%/°C Total Drift at 370 ppm: <0.4 ppm/°C RMS Noise at 370 ppm with 1 second signal filtering: < 1 ppm Span Drift: <...
  • Page 80 Appendix A Internal Optical Bench Volume: 14.5 mL. Signal Averaging: 0-20 seconds (user-selectable) Source Life: Approximately 18,000 hours. Output Signals: 0 – 5V, 0 – 2.5V, 4 – 20 mA DAC Resolution: 14-bits across specified range Power Requirements: Input Voltage 12-30 VDC (low power light comes on at approximately 10 VDC) 1.2A @ 12V (14W) maximum during warm-up with heaters on.

  • Page 81: Appendix B. Pin Assignments

    Pin Assignments DB-9 Connector Data (RXD) Data (TXD) Signal Ground (SG) Appendix B...
  • Page 82 Suppliers The company names, addresses, and phone numbers are the most current we have at the time of this printing. In some cases the information may change without notice. Soda Lime (6-12 mesh) and Magnesium Perchlorate (Anhydrous) Mg(ClO GFS Chemicals P.O.
  • Page 83 Appendix C 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 Mg(ClO : Part #M54-500 (500g) Toll free: 800-776-7000 Toll free FAX: 800-926-1166 Thomas Scientific P.O. Box 99 Soda Lime: Part #C703-B76...

  • Page 84: Appendix D. Configuration Grammar

    LI-820 Communications and XML The configuration grammar used to communicate with the LI-820 is based upon a subset of the eXtensible Markup Language (XML). XML relies on the use of tags to "Markup", or give structural rules to a set of data.
  • Page 85 Appendix D Elements are the basic unit of XML content. An element consists of a start tag and an end tag, and everything in between. For example, consider the following element: <NAME>George</NAME>. In this example, (start tag) and (end tag) comprise the markup, and <NAME>...
  • Page 86 Appendix D Connecting and Configuring Data Output The LI-820 communicates through a serial port on the front of the instrument. This port is configured as follows: Baud Rate: 9600 bps Data Bits: 8 Parity: None Stop Bits: 1 Flow Control: None After a serial connection is established, the LI-820 will immediately send data out the serial port in the manner in which it was configured previously.
  • Page 87 </LI820> Sending Data to the LI-820 To send data to the LI-820, each string must end with a '\n' to ensure that the LI-820 can parse consecutive commands. After data have been sent to the LI-820, the instrument replies with: <LI820><ACK>TRUE</ACK></LI820>...
  • Page 88 Polling the Current State of the LI-820 The LI-820 can be polled for individual sets of data by sending an XML document with a '?' in place of the set of elements requested. The element sets that can be requested include the data set, the current configuration, and the entire state of the instrument.
  • Page 89 To receive the entire state of the instrument as an XML document, send this command: <LI820>?</LI820>. Calibration The LI-820 calibration (zero and span) can be performed using XML grammar. This is accomplished in three steps: Send the calibration command to the LI-820.
  • Page 90 Appendix D An acknowledgement is returned from the LI-820 if the command was accepted. <LI820><ACK>TRUE</ACK></LI820> After about a minute, all of the calibration information is returned from the LI-820, indicating that it has finished the zero and/or span. <LI820> <CAL>...
  • Page 91 Wait for the acknowledgement. Wait for the date to be returned to verify the zero operation succeeded. If the operation fails an <ERROR> will be sent. To Span the LI-820 Send the XML command to initiate the span. <LI820> <CAL>...
  • Page 92 Appendix D To Perform a Two Point Span Send the XML command to initiate the first span. <LI820> <CAL> <DATE>YYYY-MM-DD</DATE> <CO2SPAN_A>Gas Concentration</CO2SPAN_A> </CAL> </LI820> Wait for the acknowledgement. Wait for the date to be returned to verify the span operation succeeded. If the operation fails an <ERROR>...
  • Page 93 Appendix D Wait for the date to be returned to verify the span operation succeeded. If the operation fails an <ERROR> will be sent. LI-820 XML Grammar and Element Description Data Types in the XML Grammar {val | val |...} The value will be a member of the specified set.
  • Page 94 Appendix D <CO2ABS>{float}</CO2ABS> <CELLTEMP>{float}</CELLTEMP> <CELLPRES>{float}</CELLPRES> <IVOLT>{float}</IVOLT> <RAW>{integer}</RAW> </DATA> <RS232> <CO2>{bool}</CO2> <CO2ABS>{bool}</CO2ABS> <CELLTEMP>{bool}</CELLTEMP> <CELLPRES>{bool}</CELLPRES> <IVOLT>{bool}</IVOLT> <STRIP>{bool}</STRIP> <ECHO>{bool}</ECHO> <RAW>{bool}</RAW> </RS232> <CFG> <OUTRATE>{float}</OUTRATE> <HEATER>{bool}</HEATER> <PCOMP>{bool}</PCOMP> <FILTER>{int}</FILTER> <ALARMS> <ENABLED>{bool}</ENABLED> <HIGH>{int}</HIGH> <HDEAD>{int}</HDEAD> <LOW>{int}</LOW> <LDEAD>{int}</LDEAD> </ALARMS> <BENCH>{5|14}</BENCH> Appendix D D-11...
  • Page 95 Appendix D <DACS> <RANGE>{2.5 | 5.0}</RANGE> <D1>{NONE | CO2 | CELLTEMP | CELLPRES}</D1> <D1_0>{float}</D1_0> <D1_F>{float}</D1_F> <D2>{NONE | CO2 | CELLTEMP | CELLPRES}</D2> <D2_0>{float}</D2_0> <D2_F>{float}</D2_F> </DACS> </CFG> <CAL> <DATE>{iso date}</DATE> <CO2ZERO>{bool}</CO2ZERO> <CO2SPAN>{int}</CO2SPAN> <CO2SPAN_A>{int}</CO2SPAN_A> <CO2SPAN_B>{int}</CO2SPAN_B> <CO2LASTZERO>{iso date}</CO2LASTZERO> <CO2LASTSPAN>{iso date}</CO2LASTSPAN> </CAL> <ERROR>{string}</ERROR> </LI820> D-12 Appendix D...
  • Page 96 Appendix D Element Description Parent Value(s) Comments <LI820> N/A (root) <DATA> <LI820> is the root tag for <RS232> all XML statements. <CFG> LI-820 outputs entire <CAL> configuration. <ACK> <VER> <ERROR> Examples: <LI820>?</LI820> <LI820><ACK>TRUE</ACK></LI820> Appendix D D-13...
  • Page 97 Appendix D Parent Value(s) Comments <DATA> <LI820> <CO2ABS> <DATA> contains all data <CELLTEMP> values sent from the LI- <CELLPRES> 820. All of the elements <IVOLT> within the DATA tag are <RAW> readable only. A ? requests all data values to be output.
  • Page 98 Appendix D Parent Value(s) Comments <CO2> <DATA> Float CO2 in ppm <CO2ABS> <DATA> Float CO2 absorption <CELLTEMP> <DATA> Float Cell temperature <CELLPRES> <DATA> Float Cell pressure <IVOLT> <DATA> Float Input voltage <RAW> <DATA> Text Raw detector readings Examples: <LI820><DATA><CELLTEMP>5.16E1</CELLTEMP><CELLPRES>9.742E1 </CELLPRES><CO2>6.17E2</CO2><CO2ABS>8.94E2</CO2ABS>DATA></LI820> Parent Value(s) Comments...
  • Page 99 TRUE | FALSE R/W Input voltage <RAW> <RS232> TRUE | FALSE R/W Raw detector readings <ECHO> <RS232> TRUE | FALSE R/W Echo commands sent to LI-820 <STRIP> <RS232> TRUE | FALSE R/W Strip XML from all data sent Example: <LI820><CFG><OUTRATE>0.5</OUTRATE></CFG><RS232><STRIP>FALSE </STRIP><ECHO>FALSE</ECHO><CELLTEMP>TRUE</CELLTEMP><CO2ABS> TRUE</CO2ABS><CO2>TRUE</CO2><CELLPRES>TRUE</CELLPRES><IVOLT>...
  • Page 100 Appendix D Parent Value(s) Comments <CFG> <LI820> <OUTRATE> Elements within the <HEATER> <CFG> tag control system <PCOMP> settings. <FILTER> <ALARMS> <DACS> <BENCH> Example: <LI820><CFG><HEATER>TRUE</HEATER><PCOMP>TRUE</PCOMP></CFG> </LI820> Appendix D D-17...
  • Page 101 Appendix D Parent Value(s) Comments <OUTRATE> <CFG> 0 to 20 Output data every N seconds (0.5 s increments). <HEATER> <CFG> TRUE | FALSE R/W Turn heater on/off. <PCOMP> <CFG> TRUE | FALSE R/W Pressure compensation on/off. <FILTER> <CFG> 0 to 20 Set a 0 to 20 second filter.
  • Page 102 Appendix D Parent Value(s) Comments <ENABLED> <ALARMS> TRUE | FALSE R/W Enable alarms. <HIGH> <ALARMS> Integer High alarm on at this value. <HDEAD> <ALARMS> Integer High alarm off at this value. <LOW> <ALARMS> Integer Low alarm on at this value. <LDEAD>...
  • Page 103 Appendix D Parent Value(s) Comments <RANGE> <DACS> 2.5 | 5.0 Output voltage. 2.5V or 5.0V. <D1> <DACS> CO2 | CELLPRES | DAC1 CELLTEMP <D1_0> <DACS> Float Value where DAC1 outputs 0V <D1_F> <DACS> Float Value where DAC1 outputs full scale <D2>...
  • Page 104 Appendix D Parent Value(s) Comments <CAL> <LI820> <DATE> Calibrating <CO2ZERO> parameters. When <CO2SPAN> calibrating, <DATE> <CO2SPAN_A> must be paired with a <CO2SPAN_B> <CO2ZERO> or a <CO2LASTZERO> <CO2SPAN>. <CO2LASTSPAN> <CO2KZERO> <CO2KSPAN> <CO2KSPAN1> Parent Value(s) Comments <DATE> <CAL> 20 character The date the calibration is taking place. date <CO2ZERO>...
  • Page 105 <CO2SPAN_B> <CAL> Integer (CO2 Start part 2 of a dual CO span. ppm) <CO2LASTZERO> <CAL> 20 character The date the LI-820 was last zeroed. date <CO2LASTSPAN> <CAL> 20 character The date the LI-820 was last spanned. date <CO2KZERO> <CAL> Float Calibration zero constant.
  • Page 106 Appendix D <ACK> <LI820> TRUE | FALSE R Acknowledgement to a send command. <VER> <LI820> Text Embedded software version. <ERROR> <LI820> Text Error. Includes a message. Appendix D D-23...

  • Page 107: Warranty

    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 108 This warranty supersedes all warranties for products purchased prior to June 1, 1984, unless this warranty is later superseded. DISTRIBUTOR or the DISTRIBUTOR'S customers may ship the instruments directly to LI-COR if they are unable to repair the instrument themselves even though the DISTRIBUTOR has been approved for making such repairs and has agreed with the customer to make such repairs as covered by this limited warranty.
  • Page 109 LI-COR, inc. Environmental 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@licor.com Internet: http://www.licor.com...

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