SI-131-SS: Ultra-Narrow Field of View Infrared Radiometer Sensor

The SI-131 is an un-amplified analog sensor with a voltage output.

  • Product Name:Ultra-Narrow Field of View Infrared Radiometer Sensor
  • Item No.:SI-131-SS
  • Manufacturers:Apogee
  • Country of Origin:USA

The SI-131 is an un-amplified analog sensor with a voltage output. The sensor has a 14° half-angle field of view and a response time of 0.6 seconds. Typical applications include plant canopy temperature measurement for use in plant water status estimation, road surface temperature measurement of determination of icing conditions, and terrestrial surface (soil, vegetation, water, snow) temperature measurement in energy balance studies. Sensor includes IP67 marine-grade stainless-steel cable connector 30 cm from head to simplify sensor removal and replacement for maintenance and recalibration.

Approximate Sensitivity    20 µV per C

Output from Thermopile    Approximately -1.1 mV to 1.1 mV for a temperature difference from -55 to 55 C

Output from Thermistor    0 to 2500 mV (typical, depends on input voltage)

Input Voltage Requirement    2500 mV excitation (typical, other voltages can be used)

Measurement Range    -60 to 110 C (uncertainty has been determined for the ranges below)

Calibration Uncertainty (-20 to 65 C)     0.3 C, when target and detector temperature are within 20 C

Calibration Uncertainty (-40 to 80 C)    0.6 C, when target and detector temperature are different by more than 20 C

Measurement Repeatability    Less than 0.05 C

Stability (Long-term Drift)    Less than 2 % change in slope per year when germanium filter is maintained in a clean condition

Response Time    0.6 s, time for detector signal to reach 95 % following a step change

Field of View    14˚ half-angle

Spectral Range   8 to 14 µm; atmospheric window

Operating Environment    -55 to 80 C; 0 to 100 % relative humidity (non-condensing)

Dimensions    23 mm diameter, 60 mm length

Mass    190 g (with 5 m of lead wire)

Cable    5 m of four conductor, shielded, twisted-pair wire with TPR jacket (high water resistance, high UV stability, flexibility in cold conditions), additional cable available

Warranty    4 years against defects in materials and workmanship