Delta DVP08NTC-S, Инструкция

Страница: 10 / 33

- 9 -

Introduction to NTC and S ensitivity
T he NTC sensitivity about temperature changes also represent s resistance ’ s rate of changes, which can
be seen from the slope of the line in the chart below. The greater the slope the higher the sensitivity;
therefore, the sensitivity of line A would be higher than line B as a result of a greater slope.
Temperature (T)
Resistance
(R
)
A
High Sensitivity
B
Low Sensitivity
The result of sensitivity formula is determined by the rate of change on resistance between temperature1
and temperature2. The formula is shown below.
Sensitivity =
ln 𝑅𝑅
1
− ln 𝑅𝑅
2
1
𝑇𝑇
1
−
1
𝑇𝑇
2
=
2.3026(log 𝑅𝑅
1
− log 𝑅𝑅
2
)
1
𝑇𝑇
1
−
1
𝑇𝑇
2
Sensitivity ( 𝐾𝐾 )
𝑅𝑅
1
= 𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅 ( Ω ) 𝑅𝑅𝑅𝑅 𝑅𝑅𝑎𝑎𝑅𝑅𝑎𝑎𝑎𝑎𝑎𝑎𝑅𝑅𝑅𝑅 𝑅𝑅𝑅𝑅𝑡𝑡𝑡𝑡𝑅𝑅𝑡𝑡𝑅𝑅𝑅𝑅𝑎𝑎𝑡𝑡𝑅𝑅 𝑇𝑇
1
( 𝐾𝐾 )
𝑅𝑅
2
= 𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅 ( Ω
)
𝑅𝑅𝑅𝑅 𝑅𝑅𝑎𝑎𝑅𝑅𝑎𝑎𝑎𝑎𝑎𝑎𝑅𝑅𝑅𝑅 𝑅𝑅𝑅𝑅𝑡𝑡𝑡𝑡𝑅𝑅𝑡𝑡𝑅𝑅𝑅𝑅𝑎𝑎𝑡𝑡𝑅𝑅 𝑇𝑇
2
( 𝐾𝐾 )
For example,
PT- 42H 10K B25 B85 3435K
means the resistance value of the sensor is 10K Ω at 25°C ,
while B25 B85 3435K indicates that the sensitivity value is 3435K at a temperature between 25°C~85°C.
Sensitivity =
ln 𝑅𝑅
1
− ln 𝑅𝑅
2
1
𝑇𝑇
1
−
1
𝑇𝑇
2
=
ln 1451 − ln 10,000
1
358.15
−
1
298.15
= 3435.42 ≅ 3435
𝑅𝑅
1
= 𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅 𝑅𝑅𝑅𝑅 25°C = 10K Ω
𝑅𝑅
2
= 𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅𝑅 𝑅𝑅𝑅𝑅 85°C = 1451Ω
𝑇𝑇
1
= 25 + 273.15 = 298.15K
𝑇𝑇
2
= 85 + 273.15 = 358.15K
K = °C + 273.15
K =
5
9
× (°F − 32) + 273.15