ThermoWorks 9135-156 HART SCIENTIFIC 3-POINT IR CALIBRATOR - Manual (Page 20)

8 Thermometer Calibration
The 9135 calibrator was designed primarily for calibrating infrared thermome-
ters. However, it can also be used to calibrate certain types of RTDs. The fol-
lowing sections explain the calibration of IR thermometers and RTDs
respectively.
8.1 IR Thermometer Calibration
Infrared thermometers are calibrated by pointing them at the 9135’s IR target
and comparing their readings to the known temperature of the target. In order
to achieve accurate measurements several important conditions must be
observed:
• The IR target must first reach the desired temperature and be stable. The
green ready LED lights up when the IR target is ready for calibration. DO
NOT attempt to calibrate thermometers unless the green ready LED is lit,
otherwise accuracy may be compromised.
• The 9135’s IR target is specially coated for an emmisivity of 0.95. The
9135 should only be used to calibrate IR thermometers that are set for this
value of emmisivity. DO NOT attempt to calibrate thermometers unless
they are set for 0.95 emmisivity, otherwise accuracy may be compro-
mised.
• When calibrating IR thermometers the thermometer must “see” only the
IR target of the 9135. The thermometer must be pointed directly at the tar-
get at approximately a 90° angle and with a close enough proximity that
the target area of the thermometer is completely contained within the IR
target of the 9135. This may depend on the particular IR thermometer be-
ing used. DO NOT attempt to calibrate a thermometer unless it is close
enough to ensure that its target area falls entirely within the IR target of
the 9135, otherwise accuracy may be compromised.
• Remember that the IR target gets hot! Be careful not to touch the IR
target or let any object come into contact with it. The IR target must be
kept clean (see Section 10).
8.2 RTD Calibration
The IR target plate of the 9135 has a 3.18 mm. (0.125") hole in it that can be
used to calibrate appropriately sized RTDs as well as thermistors and
thermocouples. Access to the well is through a 6.3 mm. (0.25") hole near the
center of the right side panel. Please observe the following points when cali-
brating RTDs and other probes:
• The IR target plate must first reach the desired temperature and be stable.
The green ready LED lights up when the IR target plate is ready for cali-
21
8 Thermometer Calibration
IR Thermometer Calibration