Intelligent Temperature Measuring Instruments
About intelligent temperature measuring
instruments
Intelligent temperature transmitters
have now been introduced into the catalogues of most instrument
manufacturers, and they bring about the usual benefits associated with
intelligent instruments. Such transmitters are separate boxes designed
for use with transducers which have either a d.c. voltage output in
the millivolt range or an output in the form of a resistance change.
They are therefore suitable for use in conjunction with thermocouples,
thermopiles, resistance thermometers, thermistors and broad-band
radiation pyrometers. All of the transmitters presently available have
non-volatile memories where all constants used in correcting output
values for modifying inputs, etc., are stored, thus enabling the
instrument to survive power failures without losing such information.
The transmitters now available include adjustable damping, noise
rejection, self-adjustment for zero and sensitivity drifts and
expanded measurement range. These features allow an accuracy level of
±0.05% of full scale to be specified.
The cost of intelligent temperature transducers is significantly more
than their non-intelligent counterparts, and justification purely on
the grounds of their superior accuracy is hard to make. However, their
expanded measurement range means immediate savings are made in terms
of the reduction in the number of spare instruments needed to cover a
number of measurement ranges. Their capability for self-diagnosis and
self-adjustment means that they require attention much less
frequently, giving additional savings in maintenance costs.
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Temperature Measurements
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