Owner's Manual

SPECIFICATIONS
Calibration Traceability
Apogee SI series infrared radiometers are calibrated to the temperature of a custom blackbody cone held at
multiple fixed temperatures over a range of radiometer (detector/sensor body) temperatures. The temperature of
the blackbody cone is measured with replicate precision thermistors thermally bonded to the cone surface. The
precision thermistors are calibrated for absolute temperature measurement against a platinum resistance
thermometer (PRT) in a constant temperature bath. The PRT calibration is directly traceable to the NIST.
SI-111
SI-121
SI-131
SI-1H1
Approximate Sensitivity
60 µV per C difference
between target and
detector temperature
40 µV per C
difference between
target and detector
temperature
20 µV per C
difference between
target and detector
temperature
40 µV per C
difference between
target and detector
temperature
Output from Thermopile
Approximately -3.3 to
3.3 mV for a
temperature
difference from -55 to
55 C
Approximately -2.2
to 2.2 mV for a
temperature
difference from -55
to 55 C
Approximately -1.1
to 1.1 mV for a
temperature
difference from -55
to 55 C
Approximately -2.2
to 2.2 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)
Calibration Uncertainty (-20 to 65 C),
when target and detector temperature are
within 20 C
0.2 C
0.2 C
0.3 C
0.2 C
Calibration Uncertainty (-40 to 80 C),
when target and detector temperate are
different by more than 20 C
(see Calibration Traceability below)
0.5 C
0.5 C
0.6 C
0.5 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
(see Maintenance and Recalibration section below)
Response Time
0.6 s, time for detector signal to reach 95% following a step change
Field of View
22º half angle
18º half angle
14º half angle
32º horizontal half
angle; 13º vertical
half angle
Spectral Range
8 to 14 µm; atmospheric window (see Spectral Response below)
Operating Environment
-55 to 80 C; 0 to 100 % relative humidity (non-condensing)
Dimensions
23 mm diameter; 60 mm length
Mass
190 g (with 5m of lead wire)
Cable
5 m of four conductor, shielded, twisted-pair wire; additional cable available in multiples of 5
m; santoprene rubber jacket (high water resistance, high UV stability, flexibility in cold
conditions); pigtail lead wires