Files

The Files page is used to view, access, and download data from measurements. The LI-8250 Multiplexer stores two different kinds of files:

  • Each observation is stored into an .82z file and includes all metadata and high-frequency data that was collected during a chamber closure.
  • Daily summary files are stored in .csv files using a subset of metadata and summary data with calculated fluxes.

The Files page is made up of four panes:

  1. The Output Files pane allows you to set a date range of files and to download those files to your computer, to transfer them to a user-provided USB drive connected to the multiplexer, or to delete the files within that range.
  2. The Storage pane shows how much of the LI-8250 Multiplexer onboard storage is remaining and gives you options for how the multiplexer should behave if its storage should become full. When storage is full, you can have the multiplexer Stop taking measurements or Delete Oldest files to make room for new ones. The LI-8250 Multiplexer contains 8 GB of onboard storage which should record several months worth of data.
  3. The Summary Files pane displays a list of daily summary files that fall within the range chosen in the Output Files pane. Selecting one of the summary files expands that summary file, providing you with multiple variables you can view or chart in the Data pane.
  4. The Data pane offers two ways to view the contents of a summary file. You can view all the data in a table format by selecting the table icon or you can view two of your variables charted together based upon the variables chosen in the Summary Files pane by selecting the chart icon.

Data file structure

This section describes the structure of files downloaded from your LI-8250 Multiplexer. Two kinds of files can be downloaded from the LI-8250 Multiplexer.

  • Daily summary files
  • Raw data for a single observation in .82z files

Daily summary files

Summary data from each observation are collected into a daily summary file that can show you if your system is working properly. File names for summary files are formatted with the instrument serial number and date (serial-number-YYYYMMDD_dense_summary.csv).

Daily summary files are .csv files that contain summary values–fluxes, means, and initial values–representing a subset of all available variables in the system(see Table 6‑13). These files include a header made up of 3 lines.

  • The device that is the source of the measurement (e.g., LI-8250)
  • The variable name (e.g., DATE)
  • The units for the variable (e.g., YYYYMMDD)

.82z files

Raw data for a single observation are received in .82z files. These files are intended for use in SoilFluxPro Software to simplify the management and processing of your large soil gas flux datasets.

File names for .82z files are formatted with the instrument serial number and a time stamp (serial-number-YYYYMMDDHHMMSS.82z). These files are zip archives that include represent all measurements that occur at a given port for one observation. .82z files include two files: a data.csv file and a metadata.json file.

The data.csv file uses the same 3-line header structure as the daily summary files but includes raw time series data from one observation with every variable collected by the system. See the tables in Data dictionary for a complete list of variable definitions.

The metadata.json file is a text file containing all the observation, instrument, and flux calculation metadata. See the tables in Data dictionary for a complete list of metadata variable definitions.

Note: The .82z files do not include fluxes or summary values for any variable.

Downloading files

You can retrieve files from the LI-8250 Multiplexer in three ways:

  • Download directly from the user interface
  • Transfer to USB storage from the user interface
  • Automatic transfer to a remote server

Download from user interface

To download the files from the LI-8250 Multiplexer user interface:

  1. Connect to the LI-8250 Multiplexer user interface.
  2. Go to the Files page.
  3. Select a Start Date and Time and an End Date and Time for the range of files to download.
  4. Click the Download button.

The daily summary files and .82z files will then be downloaded to your device as a .zip file. The file name will use the serial number, the start date and time, and the date and time of download (serial-number-YYYYMMDDHHMM-YYYYMMDDHHMM).

Opening the .zip file will provide all the summary files for the dates in range and a directory. The directory contains all the .82z files separated into subdirectories, first by year, then month, then day.

Transfer to USB storage

To transfer files from the multiplexer to a USB storage device:

  1. Connect to the LI-8250 Multiplexer user interface.
  2. Go to the Files page.
  3. Select a Start Date and Time and an End Date and Time for the range of files to download.
  4. Insert a USB storage device into one of the two USB ports on the multiplexer interior panel.

Note: The USB storage device must be connected to the multiplexer. The user interface will not recognize a USB device connected to your computer.

  1. Click the USB button.

The daily summary files and .82z files will then be downloaded to your device as a .zip file. The file name will use the serial number, the start date and time, and the date and time of download (serial-number-YYYYMMDDHHMM-YYYYMMDDHHMM).

Opening the .zip file will provide all the summary files for the dates in range and a folder. The folder contains all the .82z files separated first by year, then month, then day.

Automatic transfer to remote server

The LI-8250 Multiplexer can be configured to automatically transfer daily summary files and .82z files containing raw observation data from the previous day to a remote server using FTP, SFTP, or HTTP. This will require the multiplexer to be connected to a LAN or cellular modem via Ethernet.

For instructions on transferring files to a remote server using a LAN connection, see Configuring a remote server.

For instructions on transferring files to a remote server using a cellular modem, see Connecting to a cellular modem.

Data dictionary

The data dictionary describes variable names from the files and how those variables are displayed in the user interface.

LI-8250 Multiplexer variables

Table 6‑3. LI-8250 Multiplexer data definitions. The DEVICE for these variables will be LI-8250.
Interface variable Units Data file variable Description
Temperature C T_CASE Internal temperature of the multiplexer
Pressure kPa PA Atmospheric pressure
Pressure Temperature C T_PA Atmospheric pressure sensor temperature
Pump Positive Pressure kPa PUMP_POSITIVE_PRESSURE Pressure sensor on the positive pressure side of the sampling pump
Pump Negative Pressure kPa PUMP_NEGATIVE_PRESSURE Pressure sensor on the negative pressure side of the sampling pump
Flow L M-1 FLOW Flow rate through the multiplexer to the active port.
Pump Time H PUMP_TIME Hours of sampling pump operation
Pump Setpoint   PUMP_SETPOINT Drive setting for the sampling pump
Pump Current A PUMP_CURRENT Current draw by the sampling pump
Purge Pump Time H PURGE_PUMP_TIME  Hours of purge pump operation
Purge Pump Setpoint   PURGE_PUMP_SETPOINT  Drive setting for the purge pump
Purge Pump Current A PURGE_PUMP_CURRENT Current draw by the purge pump
Purge Pump Pressure kPa PURGE_PUMP_PRESSURE Pressure sensor on the positive pressure side of the purge pump
Subsample Pressure kPa SUB_PRESSURE Ambient to subsample loop pressure differential
Subsample Flow L M-1 SUB_FLOW Flow through the subsample loop
VSO Flow Setpoint1   VSO_FLOW_SETPOINT Setting for the inlet side of the system valve manifold (Figure 1‑1)
VSO Pressure Setpoint   VSO_PRESSURE_SETPOINT Setting for the outlet side of the system valve manifold (Figure 1‑1)
VSO Flow Control Voltage V   Voltage to the inlet valve on the system valve manifold
VSO Pressure Control Voltage V   Voltage to the outlet side of the system valve manifold
Port n Current A PORTn_CURRENT Current draw through the port number listed
Solenoid Current A SOL_CURRENT Current supplied to valves and VSOs
12 VDC Current A 12VDC_CURRENT Current draw on the 12 VDC power output supply
Voltage V VIN Input voltage to multiplexer
Voltage Out V VOUT Output voltage on the nominal 24 VDC supply
12 VDC Voltage V 12VDC_VOLTAGE 12 V supply voltage
5 VDC Voltage V 5VDC_VOLTAGE 5 V supply voltage
Flow Pressure kPa FLOW_PRESSURE Pressure measurement used to determine flow rate
Subsample Flow Pressure kPa SUB_FLOW_PRESSURE Pressure measurement used to determine subsample flow rate
Port   PORT Active port being sampled
Latitude ° LATITUDE Latitude reported by GPS
Longitude ° LONGITUDE Longitude reported by GPS
Altitude m ALTITUDE Altitude reported by GPS
Satellites   SATELLITES Number of satellites
Date YYYY-MM-DD DATE Timestamp of year-month-day
Time HH:MM:SS TIME Timestamp of hours-minutes-seconds

8250-01 Extension Manifold variables

Table 6‑4. 8250-01 Extension Manifold data definitions. The DEVICE for these variables will be 8250-01 Extension Manifold.
Interface variable Units Data file variable Description
Temperature C T_CASE Internal temperature of the extension manifold
Pump Time H PUMP_TIME Hours of sampling pump operation
Pump Setpoint   PUMP_SETPOINT Drive setting for the sampling pump
Pump Current A PUMP_CURRENT Current draw by the sampling pump
Purge Pump Time H PURGE_PUMP_TIME  Hours of purge pump operation
Purge Pump Setpoint   PURGE_PUMP_SETPOINT  Drive setting for the purge pump
Purge Pump Current A PURGE_PUMP_CURRENT Current draw by the purge pump
Purge Pump Pressure kPa PURGE_PUMP_PRESSURE Pressure sensor on the positive pressure side of the purge pump
Port n Current A PORTn_CURRENT Current draw through the port number listed
Solenoid Current A SOL_CURRENT Current supplied to valves and VSOs
Voltage V VIN Input voltage to multiplexer
12 VDC Voltage V 12VDC_VOLTAGE 12 V supply voltage
5 VDC Voltage V 5VDC_VOLTAGE 5 V supply voltage
3.3 VDC Voltage V 3.3VDC_VOLTAGE 3.3 V supply voltages
Port   PORT Active port being sampled
Diag Code   DIAG_CODE Diagnostic flag bits
Table 6‑5. Multiplexer and extension manifold metadata definitions. The DEVICE for these variables will be LI-8250 or 8250-01 Extension Manifold.
Interface variable Data file variable Description
Start Time TIMESTAMP_START Timestamp at the start of an observation
Volume VOLUME Device volume
Total Volume VOLUME_TOTAL Total volume used in flux calculations
Port PORT Port number the observation was made on
Port Label PORT_LABEL User entered description associated with the port
Prepurge PREPURGE Prepurge length
Observation Length OBSERVATION Observation length
Post Purge POST_PURGE Post purge length
Horizontal HORIZONTAL Numerical value of H from chamber's HVR field
Vertical VERTICAL Numerical value of V from chamber's HVR field
Latitude LATITUDE Multiplexer latitude in decimal degrees
Longitude LONGITUDE Multiplexer longitude in decimal degrees
Serial Number SERIAL_NUMBER Device serial number
Firmware FIRMWARE Device firmware version

LI-COR chamber variables

Table 6‑6. LI-COR chamber data definitions. The DEVICE for these variables will be CHAMBER.
Interface variable Units Data file variable Description
Temperature C TA Chamber air temperature
Board Temperature C TB Chamber control board temperature
Voltage V VIN Chamber input voltage
Motor Current A MOTOR_CURRENT Current draw by chamber drive motor
State   STATE There are eight chamber states:
1 = closing; 2 = opening;
3 = parking; 4 = manual move;
5 = closed; 6 = open;
7 = parked; 8 = unknown
Table 6‑7. LI-COR chamber metadata definitions. The DEVICE for these variables will be CHAMBER.
Interface variable Units Data file variable Description
Volume cm3 VOLUME Device volume
Tube Length cm TUBE_LENGTH Length of tubing associated with the chamber used to calculate total volume
Collar Height cm COLLAR_HEIGHT Collar height
Area cm2 AREA Soil area
Closing Time s CLOSE_TIME Time it took the chamber to close
Park Position ° PARK Chamber park position
Latitude ° LATITUDE Chamber latitude in decimal degrees
Longitude ° LONGITUDE Chamber longitude in decimal degrees
Serial Number   SERIAL_NUMBER Device serial number or chamber type
Firmware   FIRMWARE Device firmware version

LI-870 CO2/H2O Analyzer variables

Table 6‑8. LI-870 CO2/H2O Analyzer data definitions. The DEVICE for these variables will be LI-870.
Interface variable Units Data file variable Description
Date YYYY-MM-DD DATE Timestamp of year-month-day
Time HH:MM:SS TIME Timestamp of hours-minutes-seconds
CO2 μmol mol-1 CO2 Carbon dioxide mole fraction
CO2 Dry μmol mol-1 CO2_DRY Carbon dioxide dry mixing ratio
H2O mmol mol-1 H2O Water vapor mole fraction
Cell Temperature C T_CELL Optical bench temperature
Cell Pressure kPa PA_CELL Pressure in the optical bench
CO2 Absorption   CO2_ABS Absorption by carbon dioxide
H2O Absorption   H2O_ABS Absorption by water vapor
Voltage V VIN Input voltage to the LI-870
Flow L M-1 FLOW Flow rate through the LI-870
Table 6‑9. LI-870 metadata definitions. The DEVICE for these variables will be LI-870.
Interface variable Units Data file variable Description
Volume cm3 VOLUME Device volume
Tube Length cm TUBE_LENGTH Length of tubing associated with the analyzer used to calculate total volume
Serial Number   SERIAL_NUMBER Device serial number
Firmware   FIRMWARE Device firmware version

LI-78xx Trace Gas Analyzer variables

Table 6‑10. LI-78xx Trace Gas Analyzer data definitions. The DEVICE for these variables will be LI-7810, LI-7815, or LI-7820.
Interface variable Units Data file variable Description
Date YYYY-MM-DD DATE Timestamp of year-month-day
Time HH:MM:SS TIME Timestamp of hours-minutes-seconds
CO2 Dry μmol mol-1 CO2_DRY Carbon dioxide dry mixing ratio (LI-7810 and LI-7815 only)
H2O mmol mol-1 H2O Water vapor mole fraction
CH4 Dry nmol mol-1 CH4_DRY Methane dry mixing ratio (LI-7810 only)
N2O Dry nmol mol-1 N2O_DRY Nitrous oxide dry mixing ratio (LI-7820 only)
Diagnostic   DIAGNOSTIC Diagnostic value indicating the quality of the data and state of the instrument
Cavity Temperature C T_CAVITY Optical cavity temperature
Cavity Pressure kPa PA_CAVITY Optical cavity pressure
Laser Pressure kPa PA_LASER_PHASE Pressure used to control the laser phase
Laser Temperature C T_LASER Temperature of the laser
Residual   RESIDUAL Residual of absorption spectrum fit
Ring Down μs RING_DOWN Ring down time
Enclosure Temperature C T_THERMAL_ENCLOSURE Temperature of the optical cavity enclosure
Phase Error   PHASE_ERROR Error between setpoint and actual laser phase in counts
Shift Temperature C T_LASER_SHIFT Difference between factory set laser temperature and operating laser temperature
Voltage V VIN Input voltage to the LI-78xx
Table 6‑11. LI-78xx metadata definitions. The DEVICE for these variables will be LI-7810, LI-7815, or LI-7820.
Interface variable Units Data file variable Description
Volume cm3 VOLUME Device volume
Tube Length cm TUBE_LENGTH Length of tubing associated with the analyzer used to calculate total volume
Serial Number   SERIAL_NUMBER Device serial number
Firmware   FIRMWARE Device firmware version

Flux variables

Table 6‑12. Flux metadata definitions. The DEVICE for these variables will be FLUX.
Interface variable Units Data file variable Description
Deadband s DEADBAND Deadband length
Stop Time s STOP_TIME Length of data used for the flux computation
Dilution Source   DILUTION_SOURCE Name of the device that provided the water vapor measurement used for dilution correction (NONE for a dry gas)
Dilution Units   DILUTION_UNIT Units of water vapor measurement (NONE for a dry gas)
Temperature   TEMPERATURE Label of the temperature measurement used in flux calculation
Temperature Source   T_SOURCE Device of temperature measurement used in flux calculation
Gas   GAS Name of the gas species the flux was computed for
Gas Source   GAS_SOURCE Name of the device that measured the gas for which the flux was computed
Replicate   REPLICATE Numerical value of R from the chamber's HVR field

Summary file variables

In Table 6‑13 you will find the variables included in a summary file. Under the Label column, variables listed with Fgas will vary based upon the gas species measured by the analyzer. Under the Device column, variables listed with FLUX_source vary based upon the device (instrument) used. For example a flux of CO2 calculated using an LI-870 CO2/H2O Analyzer would appear as: FLUX_LI-870, FCO2_DRY, [μmol mol-1].

Table 6‑13. Summary file variables.
Label Units Device Description
Fgas nmol m-2s-1,
μmol m-2s-1, or
mmol m-2s-1		 FLUX_source Flux of the gas species based on exponential fit
Fgas_dCdt nmol mol-1s-1,
μmol mol-1s-1, or
mmol mol-1s-1		 FLUX_source Slope used to compute flux
Fgas_CV   FLUX_source CV for flux calculation
Fgas_R2   FLUX_source Regression coefficient of fit to accumulation curve
Fgas_SEI   FLUX_source Standard error for the intercept
Fgas_SES   FLUX_source Standard error for the slope
Fgas_A   FLUX_source Curvature parameter of exponential fit
Fgas_Cx nmol mol-1,
μmol mol-1, or
mmol mol-1		 FLUX_source Asymptotic gas concentration
Fgas_C0 nmol mol-1,
μmol mol-1, or
mmol mol-1		 FLUX_source Gas concentration at time zero
Fgas_T0 s FLUX_source Time zero for fitting accumulation curve
Fgas_ITER   FLUX_source Number of iterations required to fit the exponential model
Fgas_N   FLUX_source Number of data points used in the flux calculation
DATE YYYY-MM-DD LI-8250 Date at the start of the observation
TIME HH:MM:SS LI-8250 Time at the stat of the observation
DOY   LI-8250 Decimal day of the year at the start of the measurement
PORT   LI-8250 or
8250-01		 Port being sampled
H   CHAMBER Horizontal value from HVR
V   CHAMBER Vertical value from HVR
LATITUDE ° CHAMBER Chamber or multiplexer latitude
LONGITUDE ° CHAMBER Chamber or multiplexer longitude
TA C CHAMBER Air temperature used in flux calculation
PA kPa LI-8250 Pressure used in flux calculation
CO2_DRY μmol mol-1 LI-870 or
LI-78xx		 Carbon dioxide dry mixing ratio
CH4_DRY nmol mol-1 LI-7810 Methane dry mixing ratio
H2O mmol mol-1 LI-870 or
LI-78xx		 Water vapor mole fraction
N2O_DRY nmol mol-1 LI-7820 Nitrous oxide dry mixing ratio
Ancillary SDI-12 or light sensor data   CHAMBER Data from connected sensors