All IRt/cs are self-powered devices, relying on inco-
ming infrared radiation to produce a signal through
thermoelectric effects. Accordingly, the signal will
follow the rules of radiation thermal physics, and be
subject to the non-linearities inherent in the process.
However, over a range of temperatures, the IRt/c
output is sufficiently linear to produce a signal which
can be interchanged directly for a conventional t/c
signal. For example, specifying a 2% match to t/c
linearity results in a temperature range in which the
IRt/c will produce a signal within 2% of the conventi-
onal t/c operating over that range. Specifying 5% will
produce a somewhat wider range, etc.
Each IRt/c model is specifically designed for opti-
mum performance in the region of best linear fit with
conventional t/cs. It can howeverbe used outside of
this range by simply calibrating the readout device
appropriately. The output signal is smooth and
continuous over its entire rated temperature range,
and maintains 0.01°C (0.02°F) repeatability over its
entire range.
The linear region matches the conventional t/c to a
specified tolerance.
The actual signal generated by the IRt/c can be ap-
proximated with a fourth-order polynomial function
of target temperature. This fourth power dependence
is due to radiation physics, and not a limitation of
the IRt/c.
The Temperature Selection Guide is a summary of the
linear range performance of each IRt/c model.
Signal produced by the IRt/c-K-80F/27C has its 2%
linear range centered at 27°C (80°F), but produces a
repeatable signal to 650°C (1,200°F).