Fluke Hart Scientific 1575 Super-Thermometer, Руководство пользователя

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r t C
R t
t
t
R
( [ ])
° =
+ − −
⎛
⎝⎜
⎞
⎠⎟
⎡
⎣⎢ ⎤
⎦⎥
⎧
⎨
⎩
⎫
⎬
⎭
≥
0
0
1
1
100 100
1 0
α δ
1
100 100
1
100
1
100
3
+ − −
⎛
⎝⎜
⎞
⎠⎟ −
−
⎛
⎝⎜
⎞
⎠⎟
⎛
⎝⎜
⎞
⎠⎟
⎡
⎣
⎢
α δ β
t
t t t t
⎤
⎦
⎥
⎧
⎨
⎩⎪
⎫
⎬
⎭
<
⎧
⎨
⎪
⎪
⎩
⎪
⎪
t 0
7.4.3.2.4 Polynomial
The POLYNOMIAL conversion can be used with non-standard temperature
sensors that you fit to a polynomial equation. The equation has the form,
t R C A A R A R A R A R ( )[ ]
° = + + + +
0 1 2
3
3
3
10
10
K
If the desired polynomial equation is less than order ten, set the unnecessary
higher order coefficients to 0.
7.4.3.2.5 Thermistor
The thermistor conversions use the Steinhart-Hart equation or its inverse as
shown below. The 1575/1590 can use coefficients for either of the two equa-
tions. If your probe has coefficients for temperature as a function of resistance,
select THRM-T(R). If the coefficients are for resistance as a function of tem-
perature equation, select THRM-R(T). If there is no coefficient for the second
order term set A
2
or B
2
to 0.
T R K A A InR A InR A InR ( )[ ] [ ( ) ( ) ]
= + + +
−
0 1 2
2
3
3 1
R T K B B T B T B T ( [ ]) exp[ ]
= + + +
− − −
0 1
1
2
2
3
3
7.4.3.2.6 Resistance
The R(
Ω
) option causes the measurement to be displayed as a resistance in
ohms rather than temperature. The resistance is displayed for the probe regard-
less of the selected system units. There are no coefficients for this conversion
option.
7.4.3.2.7 W(T
90
)
The W(T
90
) option causes the measurement to be displayed as an ITS-90 resis-
tance ratio rather than temperature. The ratio is displayed for the probe regard-
49
7 Front Panel Operation
Probe Menu
Coefficients
Coefficient
Values
R
0
100.0
α
0.00385055
δ
1.4998
β
0.109
Table 3 DIN-43760/IEC-751/ASTM
E1137 Callendar-Van Dusen
Coefficients