Keithley 2701, User Manual

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F-8 Temperature Equations Model 2701 User’s Manual
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 based on different
temperature ranges. There is an equation for the -200° to 0°C range and one for the 0° to
630°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 Table F-10.
Equation for 0° to 630°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 Table F-10.
2701-900-01.book Page 8 Wednesday, August 3, 2011 9:43 AM