Technical documents
FAQRTD (PT-100)
Resistance thermometers, also called resistance temperature detectors (RTDs), are sensors used to measure temperature. Many RTD elements consist of a length of fine wire wrapped around a ceramic or glass core but other constructions are also used. The RTD wire is a pure material, typically platinum, nickel, or copper. The material has an accurate resistance/temperature relationship which is used to provide an indication of temperature. As RTD elements are fragile, they are often housed in protective probes.
Common Temperature Probes style
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| Industral Head | Transition Joint Probes | Handheld |
RTD temperature and resistance correspondence table
Resistance thermometer standard
DIN EN 60751 Class A and Class B
α=0.00385 ITS-90
t≥0°C：
R(t)=R0⋅(1+A⋅t+B⋅t2)
with
A=3.9083⋅10-3°C-1
B=-5.775⋅10-7°C-2
R0=100Ω
t<0°C：
R(t)=R0⋅[1+A⋅t+B⋅t2+C⋅(t-100°C)⋅t3)]
with
A=3.9083⋅10-3°C-1
B=-5.775⋅10-7°C-2
C=-4.183⋅10-12°C-4
R0=100Ω
Class B：
dt=±(0.3+0.005⋅|t|)°C
1/3 DIN=1/3⋅ Class B dt
1/5 DIN=1/5⋅ Class B dt
1/10 DIN=1/10⋅ Class B dt
Class A：
dt=±(0.15+0.002⋅|t|)°C
RTD accuracy comparison table
DIN 43760. IEC 751 BS 1904
| °C | 1/10 DIN | 1/5 DIN | 1/3 DIN | CLASS A | CLASS B | CLASS C | ||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| ±°C | ±Ω | ±°C | ±Ω | ±°C | ±Ω | ±°C | ±Ω | ±°C | ±Ω | ±°C | ±Ω | |
| -200 | 0.13 | 0.06 | 0.26 | 0.11 | 0.44 | 0.19 | 0.55 | 0.24 | 1.3 | 0.56 | 2.27 | 1.15 |
| -100 | 0.08 | 0.03 | 0.16 | 0.06 | 0.27 | 0.11 | 0.35 | 0.14 | 0.8 | 0.32 | 1.77 | 0.71 |
0 |
0.03 | 0.01 | 0.06 | 0.02 | 0.1 | 0.04 | 0.15 | 0.06 | 0.3 | 0.12 | 1.27 | 0.5 |
100 |
0.08 | 0.03 | 0.16 | 0.05 | 0.27 | 0.1 | 0.35 | 0.13 | 0.8 | 0.3 | 1.77 | 0.67 |
200 |
0.13 | 0.05 | 0.26 | 0.1 | 0.44 | 0.16 | 0.55 | 0.2 | 1.3 | 0.48 | 2.27 | 0.83 |
300 |
0.18 | 0.06 | 0.36 | 0.13 | 0.6 | 0.21 | 0.75 | 0.27 | 1.8 | 0.64 | 2.77 | 0.98 |
400 |
0.23 | 0.08 | 0.46 | 0.16 | 0.77 | 0.26 | 0.95 | 0.33 | 2.3 | 0.79 | 3.27 | 1.1 |
500 |
0.28 | 0.09 | 0.56 | 0.19 | 0.94 | 0.31 | 1.15 | 0.38 | 2.8 | 0.93 | 3.77 | 1.22 |
600 |
0.33 | 0.1 | 0.66 | 0.21 | 1.1 | 0.35 | 1.35 | 0.43 | 3.3 | 1.06 | 4.27 | 1.32 |
650 |
0.36 | 0.11 | 0.72 | 0.23 | 1.2 | 0.38 | 1.45 | 0.46 | 3.6 | 1.13 | 4.52 | 1.36 |
700 |
- | - | - | - | - | - | - | - | 3.8 | 1.17 | 4.77 | 1.41 |
800 |
- | - | - | - | - | - | - | - | 4.3 | 1.28 | 5.27 | 1.49 |
850 |
- | - | - | - | - | - | - | - | 4.6 | 1.34 | 5.52 | 1.56 |
