DAQ6510 Data Acquisition and Multimeter System Calibration and Adjustment Manual
Section 2: Performance verification
DAQ6510-905-01 Rev. D June 2022
2-21
RTD equations
The temperature versus resistance readings listed in the RTD reference tables are calculated using
the Callendar-Van Dusen equation. There are two equations that are based on different temperature
ranges. There is an equation for the –200 °C to 0 °C range and one for the 0 °C to 850 °C range.
Equation for –200 °C to 0 °C temperature range
R
RTD
= R
0
[1 + AT + BT
2
+ CT
3
(T – 100)]
where:
•
R
RTD
is the calculated resistance of the RTD
•
R
0
is the known RTD resistance at 0 °C
•
T is the temperature in °C
•
A = alpha [1 + (delta/100)]
•
B = –1 (alpha)(delta)(1E-4)
•
C = –1 (alpha)(beta)(1E-8)
The alpha, beta, and delta values are listed in the following table.
Equation for 0 °C to 850 °C temperature range
R
RTD
= R
0
(1 + AT + BT
2
)
where:
•
R
RTD
is the calculated resistance of the RTD
•
R
0
is the known RTD resistance at 0 °C
•
T is the temperature in °C
•
A = alpha [1 + (delta/100)]
•
B = –1 (alpha)(delta)(1E-4)
The alpha and delta values are listed in the following table.