The most widely measured phenomena in the process
control environment is temperature. Common
elements, such as Resistance Temperature Detectors
(RTDs), thermistors [ 7], thermocouples [ 6] or diodes
are used to sense absolute temperatures, as well as
changes in temperature. For an overview and compar-
ison of these sensors, refer to Microchip’s AN679,
“Temperature-Sensing Technologies” [ 5].
Of these technologies, the platinum RTD temperature-
sensing element is the most accurate, linear and stable
over time [ 1] and temperature. RTD element technolo-
gies are constantly improving, further enhancing the
quality of the temperature measurement. Typically, a
data acquisition system conditions the analog signal
from the RTD sensor, making the analog translation of
the temperature usable in the digital domain. AN687
Precision Temperature-Sensing With RTD Circuits
Author: Bonnie C. Baker RTD OVERVIEW
Microchip Technology Inc. The acronym “RTD” is derived from the term “Resis-
tance Temperature Detector” [ 4]. The most stable,
INTRODUCTION linear and repeatable RTD is made of platinum metal.
The temperature coefficient of the RTD element is
The most widely measured phenomena in the process positive and almost constant.
control environment is tempe……
