Hioki CKT3548, User Manual, Page: 85 / 86

Changzhou Chuangkai Electronic Co.,Ltd Edition V1.0
85
Appx. 5 on temperature conversion function (
△
T)
Utilizing the temperature-dependent nature of resistance, the temperature
conversion function converts resistance measurements for display as
temperatures. This method of temperature conversion is described here.
According to IEC 60034, the resistance law may be applied to determine
temperature increase as follows:
Example
With resistance R
1
of 200m
Ω at initial temperature t
1
of 20°C, and measured
resistance R
2
of 210
mΩ at current ambient temperature t
2
of 25°C, the
temperature increase value is calculated as follows:
Therefore, the current temperature t
R
of the resistive body can be calculated
as follows:
For a measurement target that is not copper or aluminum with a temperature
coefficient of a
t0
, the constant k can be calculated using the formula shown for
the temperature correction function and the above formula, as follows:
For example, the temperature coefficient of copper at 20°C is 3930 ppm/°C,
so the constant k in this case is as follows, which shows almost the same value
as the constant for copper 235 defined by the IEC standard.