Data dictionary - measured variables

The data dictionary describes variable names from the files and how those variables are displayed in the user interface and available in data files. Each component and sensor can contribute data to the dataset, as described below.

LI-8250 Multiplexer measured variables

The LI-8250 provides data about itself, including status and performance information. Measured variables indicate the performance characteristics and status of the device.

Table 7‑3. LI-8250 Multiplexer data definitions. The DEVICE for these variables is LI-8250.
Interface variable Units Data file variable Description
DOY   DOY Decimal day of year at start of measurement
Date Time YYYY-MM-DD HH:MM:SS DATE_TIME Combined date and time timestamps
Date YYYY-MM-DD DATE Timestamp of year-month-day
Time HH:MM:SS TIME Timestamp of hours-minutes-seconds
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 accessory required)
Purge Pump Setpoint   PURGE_PUMP_SETPOINT  Drive setting for the purge pump (purge pump accessory required)
Purge Pump Current A PURGE_PUMP_CURRENT Current draw by the purge pump (purge pump accessory required)
Purge Pump Pressure kPa PURGE_PUMP_PRESSURE Pressure sensor on the positive pressure side of the purge pump (purge pump accessory required)
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 Voltage Sensitive Orifice on the inlet side of the system valve manifold
VSO Pressure Setpoint   VSO_PRESSURE_SETPOINT Setting for Voltage Sensitive Orifice on the outlet side of the system valve manifold
Port n Current A PORTn_CURRENT Current draw through the port number n
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
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
5 VDC Voltage V 5VDC_VOLTAGE 5 V supply voltage
12 VDC Voltage V 12VDC_VOLTAGE 12 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
Latitude ° LATITUDE Latitude reported by GPS
Longitude ° LONGITUDE Longitude reported by GPS
Satellites   SATELLITES Number of satellites
Altitude m ALTITUDE Altitude reported by GPS

8250-01 Extension Manifold measured variables

Measured variables indicate the performance characteristics and status of the device.

Table 7‑4. 8250-01 Extension Manifold data definitions. The DEVICE for these variables is 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 accessory required)
Purge Pump Setpoint   PURGE_PUMP_SETPOINT  Drive setting for the purge pump (purge pump accessory required)
Purge Pump Current A PURGE_PUMP_CURRENT Current draw by the purge pump (purge pump accessory required)
Purge Pump Pressure kPa PURGE_PUMP_PRESSURE Pressure sensor on the positive pressure side of the purge pump (purge pump accessory required)
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
Diag Code   DIAG Diagnostic flag bits

8250-02 Calibration Manifold measured variables

The Calibration Manifold provides additional parameters related to the automated calibration and adjustments.

Table 7‑5. 8250-02 Calibration Manifold variables. The device for these variables is 8250-02 Calibration Manifold.
Interface variable Units Data file variable Description
Flow L M-1 flow Flow of calibration gas
VSO V vso Control voltage to Voltage Sensitive Orifice (an internal flow controlling valve)
VIN V vin Input voltage
Current A isys Current drawn (amps)

Long-term Chamber measured variables

The long-term soil chambers (8200-104 and 8200-104C) provide data about themselves. Measured variables indicate the performance characteristics and status of the chamber.

Table 7‑6. LI-COR chamber data definitions. The DEVICE for these variables is 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 Chamber states are:
1 = closing; 2 = opening;
3 = parking; 4 = manual move;
5 = closed; 6 = open;
7 = parked; 8 = unknown
Diagnostic   DIAG Encoded diagnostic information (see Chamber diagnostic codes).
Soil Moisture m3 m-3 SWC_1 Optional soil water content, if you a sensor contributing this data, it well be available in SoilFluxPro.
Soil Temperature ° TS_1 Optional soil temperature, if you have a sensor contributing this data, it will be available in SoilFluxPro.
Elapsed Time s ETIME Elapsed time of the measurement.

LI-870 CO2/H2O Analyzer measured variables

The LI-870 provides gas measurements and data about itself. These parameters indicate the performance characteristics and status of the gas analyzer.

Table 7‑7. LI-870 CO2/H2O Analyzer data definitions. The DEVICE for these variables is LI-870.
Interface variable Units Data file variable Description
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
Dewpoint C DEWPOINT Dewpoint temperature
Voltage V VIN Input voltage to the LI-870
Flow L M-1 FLOW Flow rate through the LI-870

LI-78xx Trace Gas Analyzers measured variables

LI-78xx Trace Gas Analyzers report measurement data and performance information. Measured variables indicate the performance characteristics and status of the Trace Gas Analyzer. Items included depend on the gas analyzer connected.

Table 7‑8. LI-78xx Trace Gas Analyzer data definitions. The DEVICE for these variables is LI-7810, LI-7815, LI-7820, or LI-7825.
Interface variable Units Data file variable Description
Diagnostic   DIAGNOSTIC Diagnostic value indicating the quality of the data and state of the instrument
CO2 Dry μmol mol-1 CO2_DRY Carbon dioxide dry mixing ratio (LI-7810, LI-7815, or LI-7825)
H2O mmol mol-1 H2O H2O vapor mole fraction
CH4 Dry nmol mol-1 CH4_DRY CH4 dry mixing ratio (LI-7810 only)
N2O Dry nmol mol-1 N2O_DRY N2O dry mixing ratio (LI-7820 only)
16O12C16O μmol mol-1 16O12C16O_DRY C12 CO2 mixing ratio (LI-7825 only)
16O13C16O μmol mol-1 16O13C16O_DRY C13 CO2 mixing ratio (LI-7825 only)
16O12C18O μmol mol-1 16O12C18O_DRY O18 CO2 mixing ratio (LI-7825 only)
16O12C17O μmol mol-1 16O12C17O_DRY O17 CO2 mixing ratio (LI-7825 only)
δ13CCO2 ‰ CO2C13 C12:13 isotopic ratio of CO2 (LI-7825 only)
δ17OCO2 ‰ CO2O17 O16:17 isotopic ratio of CO2 (LI-7825 only)
δ18OCO2 ‰ CO2O18 O16:18 isotopic ratio of CO2 (LI-7825 only)
NH3 Dry nmol mol-1 NH3_DRY NH3 dry mixing ratio (LI-7825 only)
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