7½ Digit Graphical Sampling Multimeter Calibration Manual Section 2:
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 (
)
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