YOKOGAWA 2553A, Руководство пользователя

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Appendix
App-5
IM 2553A-01EN
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App
Index
Appendix 4 User Definitions of Thermocouples and
RTDs
On the 2553A, you can define (user-define) thermoelectromotive force and resistance that simulate
those of thermocouples or RTDs and source thermoelectromotive force and resistance according to
the definitions.
Features
Thermoelectromotive Force of a Thermocouple
You can define a thermocouple’s thermoelectromotive force source for every temperature range using
polynomials. For details on the polynomial syntax, see “Definition Specifications” later in this section.
Temperature
range 1
Polynomial
Polynomial
Thermoelectromotive
force Eu [μV]
Polynomial
Temperature
range 2
Temperature range k
Temperature t [°C]
Σ
a
1i
t
1
i
Σ
a
2i
t
2
i
Σ
a
ki
t
k
i
Lower limit of
temperature
range 1
Upper limit of
temperature
range 1
Lower limit of
temperature
range 2
Upper limit of
temperature
range 2
Lower limit of
temperature
range k
Eu( t )
Reference junction temperature t
r
Thermoelectromotive
force Eu(t
r
) at reference
junction temperature t
r
The 2553A calculates thermoelectromotive force Eu
out
[µV] at temperature t [°C] using the polynomial
and the following expression and outputs the resultant value. If the reference junction temperature is
not in any of the user-defined temperature ranges, the temperature is assumed to be 0.0°C for the
calculation (reference junction compensation).
Eu
out
= Eu(t) – Eu(t
r
)
Resistance of an RTD
You can define an RTD’s resistance source for every temperature range using polynomials. For details
on the polynomial syntax, see “Definition Specifications” later in this section.
Temperature
range 1
Polynomial
Polynomial
Resistance Ru [Ω]
Polynomial
Temperature
range 2
Temperature range k
Temperature t [°C]
Σ
a
1i
t
1
i
Σ
a
2i
t
2
i
Σ
a
ki
t
k
i
Lower limit of
temperature
range 1
Upper limit of
temperature
range 1
Lower limit of
temperature
range 2
Upper limit of
temperature
range 2
Lower limit of
temperature
range k
Ru( t )
The 2553A calculates resistance Ru [Ω] at temperature t [°C] using the polynomial and outputs the
resultant value.