One of the outstanding features of the IRt/c is its
speed of response – 0.05 to 0.2 seconds. This attri-
bute makes it possible to monitor the temperature
of fast-moving materials in production lines, and
rapid heating and cooling. For applications in which
high speed is required, care should be taken in selec -
tion of the readout device, since most thermocouple
readouts are much slower than the IRt/c.
In applying the IRt/c, the dynamic characteristics can
be described mathematically as a pure exponential
response, following the equation: Accordingly, the IRt/c signal can be modeled ana-
lytically for applications in which faster speeds are
required. For any given IRt/c, the time constant will be
repeatable to within a few percent, and thus can be
successfully modeled.
A common limitation in applying the IRt/c to high-
speed applications is the transit time of the target
across the field of view. The characteristic time
constant equation of response applies to the IRt/c
response only. If the target requires time to completely
fill the field of view, the transit time must be added to
the IRt/c time constant. For best results, place the IRt/c
as close as possible to the target to minimize the spot
size, and therefore the transit time effect.