7. RESISTANCE TEMPERATURE DETECTORS
Accuracy according IEC 60751n, can be 1/3,1/5,1/6 and 1/10 at 0 °C
Temperature
Class A, ±°C
Class B, ±°C
-200 °C
0,55 °C
1,3 °C
0 °C
0,15 °C
0,3 °C
+100 °C
0,35 °C
0,8 °C
+200 °C
0,55 °C
1,3 °C
+300 °C
0,75 °C
1,8 °C
+500 °C
1,15 °C
2,8 °C
+700 °C
-3,8 °C
AND TABLE
65
The most common used RTD construction is mineral insulated.
The mineral insulated type is bendable and can be used in ap-
plications with high vibration conditions.
The construction:
• 4 conductors from several materials
• Isolated with magnesium powder (MgO)
• SS outer sheath
• Available diameters: from 1.5 mm, with a measuring system
of 4 wire, up to 6.4 mm
Commercial platinum grades are produced which exhibit a
change of resistance of 0.385 ohms/°C (European Fundamen-
tal Interval). The sensor is usually made to have a resistance
of 100 ohms at 0°C, this is defned in BS EN 60751:1996.
The American Fundamental Interval is 0.392 ohms/°C.
Upon request, RTD’s such as: Pt 400, Pt500 and Pt1000.
For other international Pt100 standards, please contact our offce.
ANSI
: alpha 0.00379
instead of 0.00385 IEC
JIS
: alpha 0.003916
instead of 0.00385 IEC
MINERAL INSULATED TYPE
3
2
1
-100 0 100 200 300 400 500 600
--200
0
Tolerance ± ˚C
Class B
“1/10 DIN” Best
tolerance, B
Class A
“1/10 DIN” Best
tolerance, A
“1/10 DIN”
Theoretical but
unattainable