Data Dictionary for NIST Photovoltaic Array and Weather 

Station Datasets, v1.0

Last update: July 27, 2017
Part 1. PV Array Datasets

The Saved Data Values from Each Array

Variable Name Units Description

One-Minute 

Average/

Min/Max

Canopy (C)/ 

Ground (G)/ 

Roof (R)

AmbTemp_C C Outdoor ambient temperature Average C/G/R

Battery_A A Current to DAS battery, neg. = discharging Average C/G/R

Battery_V V Charge voltage of DAS battery Min C/G/R

ChgSource -

Charging regulator power source

0 = none

1 = solar terminals

2 = continuous terminals

Min C/G/R

ChgState -

State of charging regulator;

-1 = regulator fault

0 = no charge

1 = current limited charging

2 = cycle charging

3 = float charging

4 = battery test

Min C/G/R

CkBatt -

Status of DAS battery;

0 = normal

1 = check battery

Max C/G/R

CR1000Temp_C C

Temperature of the data logger front 

terminal panel Average C/G/R

DoorOpen -

Door sensor for DAS enclosure;

-1 = open, 0 =closed Min C/G/R

DPCBFaults -

Inverter digital power control board fault 

code Max R

GeneralFaults1 - Inverter general fault code, group 1 Max R

GeneralFaults2 - Inverter general fault code, group 2 Max R

HardwareFaults - Inverter hardware fault code Max R

InvDriveFault - Inverter drive fault code Max C/G

InverterFaults - Inverter fault code Max R

InvEtoday_kWh kWh AC total real energy from current day, 

meas. by inverter Max R

InvEtot_kWh kWh AC total accumulated real energy, meas. by 

inverter Max C/G/R

InvEtot_kWh kWh AC total accumulated real energy, meas. by 

inverter Max R

InvEyesterday_kWh kWh AC total real energy from previous day, 

meas. by inverter Max R

InvFreq Hz AC frequency, meas. by inverter Average C/G/R

InvGndImped_kOhm kΩ Inverter ground impedance Average R
InvGridFault - Inverter grid fault code Max C/G

InvIa A Line current, phase A, meas. by inverter Average C/G/R

InvIabcAvg A Average AC line current, meas. by inverter Average R

InvIb A Line current, phase B, meas. by inverter Average C/G/R

InvIc A Line current, phase C, meas. by inverter Average C/G/R

InvIDCin A Inverter DC input current, meas. by inverter Average C/G/R

InvIGnd A Inverter DC ground current Average R

InvINeutral A AC neutral current, meas. by inverter Average R

InvIUnbal %

AC line current unbalance, meas. by 

inverter Average R

InvMainFault - Inverter main fault code Max C/G

InvOpState - Inverter operating status/state Average R

InvOpStatus - Inverter operating status/state Average C/G

InvPAC_kW kW AC real power, meas. by inverter Average C/G/R

InvPDC_kW kW Inverter DC input power, meas. by inverter Average C/G/R

InvPF - AC power factor, meas. by inverter Average R

InvPVMStatus - Inverter PV monitoring status code Max C/G

InvSystemFault - Inverter system fault code Max C/G

InvSystemWarn - Inverter system warning code Max C/G

InvTempFault - Inverter temperature fault code Max C/G

InvTempHeatsink_C C Inverter heatsink temperature Average R

InvTempInternalAir_C C

Ambient temperature inside inverter general 

enclosure Average R

InvTempInverterAir_C C

Ambient temperature inside inverter 

enclosure Average R

InvVa V Line voltage, phase A, meas. by inverter Average C/G/R

InvVA_kVA kVA AC apparent power, meas. by inverter Average R

InvVabcAvg V Average AC line voltage, meas. by inverter Average R

InvVAR_kVAR kVAR AC reactive power, meas. by inverter Average R

InvVb V Line voltage, phase B, meas. by inverter Average C/G/R

InvVc V Line voltage, phase C, meas. by inverter Average C/G/R

InvVDCin V

Inverter DC input voltage on load side of 

DC contactor, meas. by inverter Average C/G/R

InvVDVoltage_V V

Array DC voltage on DC busbars, measured 

using voltage divider Average C/G/R

InvVoltageFault - Inverter voltage fault code Max C/G

InvVPVin V

Array DC voltage on line (PV) side of DC 

contactor, meas. by inverter Average C/G/R
InvVUnbal %

AC line voltage unbalance, meas. by 

inverter Average R

Load_A A

Current supplied to load (DAS) from 

charging regulator Average C/G/R

NumActiveFaults - Inverter number of active faults Max R

PwrMtrEdel_kVARh kVARh AC total accumulated reactive energy to 

(used by) inverter, meas. by AC meter Max C/G/R

PwrMtrEdel_kWh kWh AC total accumulated real energy to (used 

by) inverter, meas. by AC meter Max C/G/R

PwrMtrErec_kVARh kVARh AC total accumulated reactive energy from 

(generated by) inverter, meas. by AC meter Max C/G/R

PwrMtrErec_kWh kWh AC total accumulated real energy from 

(generated by) inverter, meas. by AC meter Max C/G/R

PwrMtrFreq Hz AC frequency, meas. by AC meter Average C/G/R

PwrMtrFreqMax Hz Max. AC frequency, meas. by AC meter Max C/G/R

PwrMtrFreqMin Hz Min. AC frequency, meas. by AC meter Min C/G/R

PwrMtrIa A Line current, phase A, meas. by AC meter Average C/G/R

PwrMtrIb A Line current, phase B, meas. by AC meter Average C/G/R

PwrMtrIc A Line current, phase C, meas. by AC meter Average C/G/R

PwrMtrP_kVA kVA AC apparent power, meas. by AC meter Average C/G/R

PwrMtrP_kVAR kVAR AC reactive power, meas. by AC meter Average C/G/R

PwrMtrP_kW kW AC real power, meas. by AC meter Average C/G/R

PwrMtrPF - AC power factor, meas. by AC meter Average C/G/R

PwrMtrPhaseRev Hz AC phase reversal, meas. by AC meter Average C/G/R

PwrMtrVa V Line voltage, phase A, meas. by AC meter Average C/G/R

PwrMtrVaTHDMax %

AC max. total harmonic distortion in phase 

A, meas. by AC meter Max C/G/R

PwrMtrVb V Line voltage, phase B, meas. by AC meter Average C/G/R

PwrMtrVbTHDMax %

AC max. total harmonic distortion in phase 

B, meas. by AC meter Max C/G/R

PwrMtrVc V Line voltage, phase C, meas. by AC meter Average C/G/R

PwrMtrVcTHDMax %

AC max. total harmonic distortion in phase 

C, meas. by AC meter Max C/G/R

Pyra1_mV mV

Millivolt output from pyranometer;

Canopy: POA, west-tilted

Ground: GHI

Roof: GHI, southwest

Average C/G/R

Pyra2_mV mV

Millivolt output from pyranometer;

Canopy: GHI

Ground: POA

Roof: GHI, southeast

Average C/G/R
Pyra3_mV mV

Millivolt output from pyranometer;

Canopy: POA, east-tilted

Roof: POA, southeast

Average C/R

Pyra4_mV mV Millivolt output from pyranometer;

Roof: GHI, northwest Average R

Pyra5_mV mV Millivolt output from pyranometer;

Roof: GHI, northeast Average R

Pyra6_mV mV Millivolt output from pyranometer;

Roof: GHI, center of older horiz. array Average R

Pyra7_mV mV

Millivolt output from pyranometer;

Roof: GHI, northwest of older horiz. 

array

Average R

Pyra8_mV mV

Millivolt output from pyranometer;

Roof: GHI, northeast of older horiz. 

array

Average R

Qloss_Ah A·h Charge deficit of DAS battery Max C/G/R

RefCell1_Wm2 W/m2

Irradiance from flat-plate silicon sensor;

Canopy: POA, west-tilted

Ground: POA

Roof: POA, southeast

Average C/G/R

RefCell2_Wm2 W/m2

Irradiance from flat-plate silicon sensor;

Canopy: POA, east-tilted

Roof: GHI, center of older horiz. array, 

east, cleaned

Average C/R

RefCell3_Wm2 W/m2

Irradiance from flat-plate silicon sensor;

Roof: GHI, center of older horiz. array, 

west, uncleaned

Average R

RTD_C(1) C

Temperature of module backsheet;

Canopy: east-tilted southwest module

Ground: center shed, northwest module

Roof: south sub-array, south-center 

module

Average C/G/R

RTD_C(10) C Ambient temperature inside inverter Average C/G/

RTD_C(2) C

Temperature of module backsheet;

Canopy: east-tilted southeast module

Ground: center shed, center module of 

west half

Roof: center-east sub array, center-east 

module

Average C/G/R

RTD_C(3) C

Temperature of module backsheet;

Canopy: west-tilted center-east module

Ground: center shed, center-bottom 

module

Roof: center-east sub array, center

module, center

Average C/G/R
RTD_C(4) C

Temperature of module backsheet;

Canopy: east-tilted center-west module, 

center

Ground: center shed, center module, center

Roof: center-east sub array, center 

module, northwest

Average C/G/R

RTD_C(5) C

Temperature of module backsheet;

Canopy: east-tilted center-west module, 

southwest

Ground: center shed, center module, 

southwest

Roof: center-east sub array, center 

module, south-center

Average C/G/R

RTD_C(6) C

Temperature of module backsheet;

Canopy: east-tilted center-west module, 

center-east

Ground: center shed, center module, 

center-east

Roof: center-east sub array, center 

module, center-east

Average C/G/R

RTD_C(7) C

Temperature of module backsheet;

Canopy: east-tilted center-west module, 

north-center

Ground: center shed, center module, northcenter

Roof: northwest sub-array, northwest 

module

Average C/G/R

RTD_C(8) C

Temperature of module backsheet;

Canopy: east-tilted center-east module

Ground: center shed, center-top module

Average C/G/

RTD_C(9) C

Temperature of module backsheet;

Canopy: east-tilted northwest module

Ground: north shed, center module

Average C/G/

SEWSAmbientTemp_C C

Outdoor ambient temperature from 

integrator’s sensor Average C/G/R

SEWSModuleTemp_C C

Module temperature from integrator’s 

sensor

Average C/G/R

SEWSPOAIrrad_Wm2 W/m2 POA irradiance from integrator’s domed 

diffused silicon-cell pyranometer Average C/G/R

ShuntCurrent_A(1) A Output circuit current from combiner box 1 Average C/G/R

ShuntCurrent_A(2) A Output circuit current from combiner box 2 Average C/G/R

ShuntCurrent_A(3) A Output circuit current from combiner box 3 Average C/G/R

ShuntCurrent_A(4) A Output circuit current from combiner box 4 Average C/G/R

ShuntCurrent_A(5) A Output circuit current from combiner box 5 Average C/G

ShuntCurrent_A(6) A Output circuit current from combiner box 6 Average C/G

ShuntCurrent_A(7) A Output circuit current from combiner box 7 Average C/G
ShuntEtot_kWh_Avg(1) kWh

Output circuit total accumulated energy 

from combiner box 1, meas. using shunts 

and voltage divider*

- C/G/R

ShuntEtot_kWh_Avg(2) kWh

Output circuit total accumulated energy 

from combiner box 2, meas. using shunts 

and voltage divider*

- C/G/R

ShuntEtot_kWh_Avg(3) kWh

Output circuit total accumulated energy 

from combiner box 3, meas. using shunts 

and voltage divider*

- C/G/R

ShuntEtot_kWh_Avg(4) kWh

Output circuit total accumulated energy 

from combiner box 4, meas. using shunts 

and voltage divider*

- C/G/R

ShuntEtot_kWh_Avg(5) kWh

Output circuit total accumulated energy 

from combiner box 5, meas. using shunts 

and voltage divider*

- C/G

ShuntEtot_kWh_Avg(6) kWh

Output circuit total accumulated energy 

from combiner box 6, meas. using shunts 

and voltage divider*

- C/G

ShuntEtot_kWh_Avg(7) kWh

Output circuit total accumulated energy 

from combiner box 7, meas. using shunts 

and voltage divider*

- C/G

ShuntPDC_kW_Avg(1) kW Output circuit power from combiner box 1, 

meas. using shunts and voltage divider* - C/G/R

ShuntPDC_kW_Avg(2) kW Output circuit power from combiner box 2, 

meas. using shunts and voltage divider* - C/G/R

ShuntPDC_kW_Avg(3) kW Output circuit power from combiner box 3, 

meas. using shunts and voltage divider* - C/G/R

ShuntPDC_kW_Avg(4) kW Output circuit power from combiner box 4, 

meas. using shunts and voltage divider* - C/G/R

ShuntPDC_kW_Avg(5) kW Output circuit power from combiner box 5, 

meas. using shunts and voltage divider* - C/G

ShuntPDC_kW_Avg(6) kW Output circuit power from combiner box 6, 

meas. using shunts and voltage divider* - C/G

ShuntPDC_kW_Avg(7) kW Output circuit power from combiner box 7, 

meas. using shunts and voltage divider* - C/G

TemperatureFaults - Inverter temperature fault code Max R

TIMESTAMP LST Date and time Max C/G/R

Warnings - Inverter system warning code Max R

WindDir_deg ° Wind direction, clockwise from north - C/G/R

WindDirAve_deg ° Unit vector mean wind direction* - C/G/R

WindDirStdDev_deg ° Standard deviation of the wind direction* - C/G/R
WindHeatStateID -

1 = heating disabled

2 = enabled, not heating

3 = 50 % heating

4 = 100 % heating

5 = error

Average C/G/R

WindRef_V V Internal reference voltage in wind sensor Min C/G/R

WindSpeed_ms m/s Wind speed Max C/G/R

WindSpeedAve_ms m/s Mean horizontal wind speed* - C/G/R

WindValid -

Wind sensor data validity

-1 = wind data is valid

0 = wind data is invalid

Average C/G/R

Note: All measurements are sampled every 1 s except the RTDs, which are sampled every 10 seconds. All 

measurements are saved every 1 s, except those marked with a “*”.

* Calculated from saved 1 s samples; only the 1 min aggregate data are saved
Part 2. Weather Station Dataset

The Saved Data Values from the Weather Station

Variable Name Units Description One-Minute 

Aggregation

Top (T)/ 

Lower (L) 

Data Logger

AirMass - Absolute air mass Average T/L

AirPres_kPa kPa Atmospheric pressure Average T

AirTemp_C C

Outdoor ambient temperature 5.59 m above 

roof Average T

AM25TRefTemp_C C Thermocouple UTR reference temperature Average L

AmbTemp_C C

Outdoor ambient temperature 1.07 m above 

roof Average L

AmbVent_rpm rev/min Mean ambient temperature ventilator fan 

speed Average* L

Battery_A A Current to UPS battery, neg. = discharging Average T/L

Battery_V V Charge voltage of UPS battery Min T/L

ChgSource -

Charging regulator power source

0 = none

1 = solar terminals

2 = continuous terminals

Min T/L

ChgState -

State of charging regulator;

-1 = regulator fault

0 = no charge

1 = current limited charging

2 = cycle charging

3 = float charging

4 = battery test

Min T/L

CkBatt -

Status of UPS battery;

0 = normal

1 = check battery

Max T/L

CR1000Temp_C C

Temperature of the data logger front 

terminal panel Average T/L

Declination_deg ° Earth’s declination angle Average T/L

DoorOpen -

Door sensor for DAS enclosure;

-1 = open, 0 =closed Min T

Hail_hitssqrcm hits/cm2 Hail count Sum T

Load_A A

Current supplied to load (UPS) from 

charging regulator Average T/L

PwrStripState - State of remote power strip, bit field Min L

Pyra1_mV mV Millivolt output from thermopile 

pyranometer, south table position Average T

Pyra1temp_C C

Thermopile pyranometer case temperature, 

south table position Average T
Pyra2_mV mV Millivolt output from thermopile 

pyranometer, north table position Average L

Pyra2temp_C C

Thermopile pyranometer case temperature, 

north table position Average L

Pyrad1_mV mV

Millivolt output from diffuse-measuring 

pyranometer, east tracker position (when 

pointing south)

Average T

Pyrad2_mV mV

Millivolt output from diffuse-measuring 

pyranometer, west tracker position (when 

pointing south)

Average L

PyraS1_Wm2 W/m2 Millivolt output from domed-diffused 

silicon-cell pyranometer Average L

Pyrg1_mV mV Millivolt output from pyrgeometer Average T

Pyrg1temp_C C Pyrgeometer case temperature Average T

Pyrh1_mV mV Millivolt output from pyrheliometer, east 

tracker position (when pointing south) Average T

Pyrh1temp_C C

Pyrheliometer case temperature, east tracker 

position (when pointing south) Average T

Pyrh2_mV mV Millivolt output from pyrheliometer, west 

tracker position (when pointing south) Average L

Qloss_Ah A·h Charge deficit of UPS battery Max T/L

Rain_mm mm Rain accumulation, piezoelectric sensor Sum T

RainTB_mm mm

Rain and precipitation liquid equivalent 

accumulation, tipping bucket gauge Sum T

RefCell1_Wm2 W/m2

Irradiance from flat-plate silicon sensor, 0° 

tilt Average T

RefCell2_Wm2 W/m2

Irradiance from flat-plate silicon sensor, 10° 

tilt, 180° azimuth CW from north Average T

RefCell3_Wm2 W/m2

Irradiance from flat-plate silicon sensor, 5° 

tilt, 270° azimuth CW from north Average T

RefCell4_Wm2 W/m2

Irradiance from flat-plate silicon sensor, 5° 

tilt, 90° azimuth CW from north Average T

RefCell5_Wm2 W/m2

Irradiance from flat-plate silicon sensor, 20° 

tilt, 180° azimuth CW from north Average T

RefCell6_Wm2 W/m2

Irradiance from flat-plate silicon sensor, 

18.4° tilt, 180° azimuth CW from north Average T

RelayState - State of latching relay, bit field Min T/L

RelHumid % Relative humidity Average T

RTD_C(1) C

Temperature of module backsheet: 10° 

tilted module, center Average L

RTD_C(10) C

Temperature of module backsheet: 5° east 

tilted module, southwest Average L

RTD_C(11) C

Temperature of module backsheet: 5° east 

tilted module, center-east Average L
RTD_C(12) C

Temperature of module backsheet: 5° east 

tilted module, north-center Average L

RTD_C(13) C

Temperature of module backsheet: 20° 

tilted module, center Average L

RTD_C(14) C

Temperature of module backsheet: 20° 

tilted module, northeast Average L

RTD_C(15) C

Temperature of module backsheet: 20° 

tilted module, center-west Average L

RTD_C(16) C

Temperature of module backsheet: 20° 

tilted module, south-center Average L

RTD_C(2) C

Temperature of module backsheet: 10° 

tilted module, northwest Average L

RTD_C(3) C

Temperature of module backsheet: 10° 

tilted module, south-center Average L

RTD_C(4) C

Temperature of module backsheet: 10° 

tilted module, center-east Average L

RTD_C(5) C

Temperature of module backsheet: 5° west 

tilted module, center Average L

RTD_C(6) C

Temperature of module backsheet: 5° west 

tilted module, northeast Average L

RTD_C(7) C

Temperature of module backsheet: 5° west 

tilted module, center-west Average L

RTD_C(8) C

Temperature of module backsheet: 5° west 

tilted module, south-center Average L

RTD_C(9) C

Temperature of module backsheet: 5° east 

tilted module, center Average L

SixInOneHeatStateID -

Weather transmitter heating state:

1 = heating disabled

2 = enabled, not heating

3 = 50 % heating

4 = 100 % heating

5 = error

Average T

SixInOneRef_V V

Internal reference voltage in weather 

transmitter Min T

SnowDepth_cm cm Snow depth Average L

SolarAzFromSouth_deg ° Solar azimuth, CW from south Average T/L

SolarTime_hr h Solar time Max, Median T/L

SolarZenith_deg ° Solar zenith angle Average T/L

TC_C(1) C

Temperature of module backsheet: 0° tilted 

module, center Average L

TC_C(2) C

Temperature of module backsheet: 0° tilted 

module, southeast Average L

TC_C(3) C

Temperature of module backsheet: 0° tilted 

module, north-center Average L
TC_C(4) C

Temperature of module backsheet: 0° tilted 

module, between center and southeast Average L

TC_C(5) C

Temperature of module backsheet: 18.4° 

tilted module, center Average L

TC_C(6) C

Temperature of module backsheet: 18.4° 

tilted module, northwest Average L

TC_C(7) C

Temperature of module backsheet: 18.4° 

tilted module, south-center Average L

TC_C(8) C

Temperature of module backsheet: 18.4° 

tilted module, center-east Average L

TIMESTAMP LST Date and time Max T/L

TrackerFlags - Tracker status, bit field Max L

TrackerState - Tracker state Min L

UVA_mV mV Millivolt output from UV-A radiometer 

converter box Average T

UVB_mV mV Millivolt output from UV-B radiometer 

converter box Average T

UVBtemp_C C

UV-B radiometer optical system 

temperature Average T

UVT_mV mV Millivolt output from UV total radiometer Average L

Vent2_rpm rev/min Mean GHI ventilator fan speed, south table 

position Average* T

Vent4_rpm rev/min Mean GHI ventilator fan speed, north table 

position Average* L

WindDir_deg °

Wind direction 5.72 m above roof, 

clockwise from north - T

WindDir1_deg °

Wind direction 2.51 m above roof, 

clockwise from north - L

WindDir1Ave_deg °

Unit vector mean wind direction 2.51 m 

above roof Average* L

WindDirAve_deg °

Unit vector mean wind direction 5.72 m 

above roof Average* T

WindDirStdDev_deg °

Standard deviation of the wind direction; 

Top: 5.72 m above roof

Lower: 2.51 m above roof

Std. Dev.* T/L

WindSpeed_ms m/s Wind speed 5.72 m above roof Max T

WindSpeed1_ms m/s Wind speed 2.51 m above roof Max L

WindSpeed1Ave_ms m/s Mean horizontal wind speed 2.51 m above 

roof Average* L

WindSpeedAve_ms m/s Mean horizontal wind speed 5.72 m above 

roof Average* T
WindValid -

Wind sensor 5.72 m above roof data 

validity

-1 = wind data is valid

0 = wind data is invalid

Average T

Note: All measurements are sampled every 1 s except the RTDs and thermocouples, which are sampled every 10 s. 

All measurements are saved every 1 s, except those marked with a “*”.

* Calculated from saved 1 s samples; only the 1 min aggregate data are saved