Rtd Sensors; Optional Platinum Sensor - Teledyne T3MIL50 User Manual

RTD Sensors

Overview

Optional Platinum Sensor

Introduction
Resistive Thermal Devices (RTDs) are commonly used as
temperature sensors. RTDs change resistance linearly over
a specific range of temperature. The table below shows
some of the inherent features of RTDs compared to
thermocouples.
Feature
Accuracy
Resolution
Speed of response
Self-heating
Long term stability
Output characteristics
The platinum sensor is a PT-100 sensor. The PT-100
sensor meets the German DIN43760: 1968 3 wire
measurement specification.
These sensors are one of the most common
temperature sensors used in industry. These sensors
have a nominal resistance of 100
The relationship between temperature and resistance
for the PT-100 sensor can be described with the
Gallendarvan Dusen equation shown below:
R =R [1+AT+BT
RTD 0
Where:
R is the calculated resistance of the RTD.
RTD
R is the known RTD resistance at 0˚C.
0
T is the temperature in˚C
A=alpha [I+(delta/100)]
B=-I(alpha)(delta)(Ie-4)
C=-I(alpha)(beta)(Ie-8)
The Alpha (A), Beta (B), Delta (D) values for the
PT-100 sensor are listed below:
Description
Higher accuracy
0.1~1.0˚C, higher resolution
Slower
Yes
Good
Approx. 0.4ohm/˚C, near linear
Ω at 0˚C.
2 3
+CT (T-100)]
APPENDIX
143