Model DMM7510 7½ Digit Graphical Sampling Multimeter Calibration Manual
Section 2: Performance verification
DMM7510-905-01 Rev. A / April 2015
2-35
RTD equations
The temperature vs. resistance readings listed in the RTD reference tables are calculated using the
Callendar-Van Dusen equation. There are two equations, which 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° 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.
RTD parameters for equations
The RTD parameters for the Callendar-Van Dusen equations are listed in the following table.
Model DMM7510 resistance to temperature device (RTD)
Type
Standard
Alpha
Beta
Delta
R
0
at 0 °C (
Ω
)
PT100
ITS-90
0.00385055
0.10863
1.49990
100.0000
D100
0.003920
0.10630
1.49710
F100
0.003900
0.11000
1.49589
PT385
IPTS-68
0.003850
0.11100
1.50700
PT3916
0.003916
0.11600
1.50594
