Using the gas analyzer

This section describes how to power on and connect to the instrument.

Powering on the instrument

The analyzer should measure ambient air during power on and initialization. Allow about one hour to complete initialization.

Caution: Remove the protective caps from the air inlet and outlet before powering on the instrument. The instrument will fail to initialize if the caps are in place. Use the caps when storing or shipping the instrument.

To power on the instrument, either install a battery and push the power button or connect the instrument to an external power supply. The instrument will power on any time power is supplied through the AC power adapter or the auxiliary power cable.

See Support: LI-8815 CO2/H2O AtmospherIQ Gas Analyzer for more details.

If main power is lost, the instrument will run until the batteries are depleted and then it will power off. When the main power is restored, the instrument will power up and the batteries will resume charging. When powered by batteries only, you must press the power button to turn on the instrument.

Upon powering on, the instrument will issue a series of status codes as it completes the start up cycle. The pump will start running when the optical bench approaches 55 °C. If starting from room temperature, it will take about 20 minutes before you can connect and another 10 or 15 minutes before it provides accurate measurements. If the instrument is very cold, it will take longer to warm up.

The instrument cannot be powered on from afar. You can restart the instrument through the software interface, but if you power it off through the software interface or the power button, you must press the button or reconnect the main power supply to turn it back on. See Powering off the instrument for additional details.

Connecting with the instrument

Connect with the instrument using a web browser on a computer, tablet, or smart phone that is on the same network as the instrument.

  1. Connect a network cable between the instrument and a computer or local network.

    When connected to a network, the instrument will display the network icon (Network status icon.) and the assigned IP address. If the local network has Wi-Fi, you can connect to the instrument over the wireless network.

  1. Enter the hostname or IP address in a web browser address bar.

    Both the hostname (which is the instrument serial number) and IP address are given on the display. Type one or the other into the address bar:

    • Hostname: Enter http://atg15-nnnnn.local where atg15-nnnnn is the hostname (and the serial number) of your instrument.
    • IP address: The IP address on the display panel.

  2. Press Enter to connect.

    The interface will load into the browser window.

    The home screen on a computer.

Unable to connect? See Connection problems for troubleshooting.

Instrument display

The instrument display panel provides useful information at a glance.

  • Serial Number and IP Address: The instrument serial number (hostname) and network-assigned IP address (IPv4) rotate for 5 seconds each. The serial number is also printed on the case label.
  • Network Status: When visible (Network status icon.), the instrument is connected to a network.
  • Battery Status: Indicates the charge status (Battery status indicator.). A solid black battery indicates a full charge; an outline indicates a discharged battery. The battery icon is not displayed when no batteries are installed.
  • Power Status: Indicates the power source (AC if power cable connected).
  • Performance Status: Indicates performance status of the instrument.
  • Gases: The gases measured and their concentrations.

Status codes

Status codes are given on the instrument display panel, software interface, and recorded in the data set, where they are associated with measurements.

Table 3‑1. Status codes provide information on the status of the instrument.
Display Indicator Software Indicator Status Code Definition
a Green 0 Normal operation (measuring).
Yellow 1 Start frequency adjustment; Measurements may be noisy.
Yellow 2 Laser temperature adjustment; Measurements may be noisy.
Yellow 4 Incomplete scan resulted in missing cavity modes; Measurements may be noisy.
Yellow 8 Start-up mode finished; Measurements may be noisy.
Yellow 16 Start-up mode initializing; Measurements may be noisy.
Red 32 Spectral fit residual RMS too high; Measurements are invalid.
Red 64 Unregulated pressures or temperatures; Measurements are invalid.
Red 128 Inlet clogged. Triggered when the inlet is obstructed for 3 or more seconds. When triggered, the instrument turns off the pump and enters sleep mode. Clear the obstructions and restart the instrument.
Red 256 Instrument not ready; Measurements are invalid.
Red   SVC Required. This message may be issued during warmup. If not resolved after 60 to 90 minutes of operation, contact LI-COR or your sales representative.
Red   SD card error. This message may be issued briefly during warmup or during a firmware update. If it persists, contact LI-COR or a sales representative.

Status codes are additive: if multiple codes are active, the displayed value is the sum of the codes. For example, a display code of 23 indicates that the instrument is initializing the start-up mode (16), it has an incomplete scan (4), laser temperature adjustment is underway (2), and a start frequency adjustment is underway (1). Non-zero status codes are displayed during warmup and any time the instrument is not in a normal state. Typically, status codes will be resolved by the instrument. Occasionally, you may need to restart the instrument to resolve the code. If a code is not dismissed for several hours or after restarting, contact technical support.

Configuration options

The instrument supports two operating configurations that can be set in the interface: Standard and High Altitude.

Standard

The standard configuration is the default - it will be loaded automatically unless the configuration has been changed under Options > Settings > Software > Configuration.

High altitude

The high altitude configuration does not require any hardware modifications. The reduced flow rate hardware modifications cannot be used while the instrument is in the high altitude configuration; if the kit has been installed, remove it before using the high altitude configuration. To use the high altitude configuration, select it under Options > Settings > Software > Configuration and restart the instrument. Be aware of slight differences in the performance specifications of the instrument while in the high altitude configuration.

See Specifications for details.

Reduced flow rate kit

The reduced flow rate kit (part number 7900-113) enables the analyzer to operate at a nominal flow rate near 70 sccm, rather than the standard nominal flow rate near 250 sccm. One kits is required to use the Reduced Flow Rate configuration. To install the kit:

  1. Power off the instrument. 
  2. Remove the nine screws that secure the top, and then remove the top.

  3. Identify the tube that connects the pump manifold to the optical bench.

    Cut the tube to install the reduced flow rate kit.
  4. Cut the tube where indicated.
  5. Observe the flow direction indicator on the assembly and install it between the two cut ends with the arrow pointing from the optical bench to the pump.
  6. For each quick connect, insert the tube and push firmly until it stops.

  8. Restart the instrument.

    The instrument will start up and operate with a flow rate of approximately 70 sccm.

To restore the normal flow rate, remove the reduced flow rate kit, connect the cut tubes with a quick-connect, and restart.

Powering off the instrument

The instrument can be powered off with the power button or through the software interface. To Power Off the instrument with the button, press it three times within 5 seconds. To enter Sleep Mode, press the power button twice within 3 seconds. In sleep mode, the instrument will power off the pump but maintain power to the heaters. Sleep mode is to silence the pumps, if, for example, you want to hear the birds singing while you walk between measurements. To Exit Sleep Mode, press the power button after waiting at least 5 seconds after the previous press.

Caution: While in sleep mode, the instrument will stop drawing in air, which may affect the pressure and flow in your air supply system. Do not enter sleep mode when the air inlet or outlet is subject to positive or negative pressure. Pressures exceeding 110 kPa absolute pressure may damage the instrument.

If a battery becomes depleted during normal operation, the instrument will complete the dry-down cycle before shutting itself down. If the instrument is inadvertently powered off and prevented from completing the dry-down cycle (by removing the batteries and power cable, for example), power it back on and off again so it can complete the dry-down cycle.

Caution: Failure to complete the dry-down while powering off the instrument may result in condensation in the optics, which will damage the instrument.