WIKA TR10-L Mode D'emploi page 11

3. Specifications
Resistance values and tolerance values with selected temperatures (Pt100)
Resistance value in Ω
Temperature
in °C
(ITS 90) Class AA
-196 -
-100 -
-50 80.23 ... 80.38
-30 88.16 ... 88.28
0 99.96 ... 100.04
20 107.74 ... 107.85
100 138.40 ... 138.61
150 157.91 ... 157.64
250 193.91 ... 194.29
-
300
450 -
500 -
600 -
This table represents the calibration process with predefined temperatures.
This means if a temperature standard is available, the resistance value of the test piece must lie within the
limits specified above.
3.2 Thermocouples
Sensor type
Model
K (NiCr-Ni)
J (Fe-CuNi)
E (NiCr-CuNi)
T (Cu-CuNi)
N (NiCrSi-NiSi)
S (Pt10% Rh-Pt)
R (Pt13% Rh-Pt)
B (Pt30% Rh-Pt6%-Rh)
Potential measuring uncertainties due to aging effects
Thermocouples age and change their temperature/thermoelectric voltage curve. Type J thermo-
couples age slightly due to oxidation of the pure metal leg. As for Type K and to a lesser extend
Type N (NiCrSi-NiSi) thermocouples, considerable changes in thermo-electric voltage can occur
at high temperatures due to chromium depletion in the NiCr leg, which results in a decreasing
thermo-electric voltage.
This effect is accelerated if there is a shortage of oxygen, since a complete oxide skin is unable to
form on the surface of the thermocouple and protect it from further oxidation. The chromium in the
alloy oxidizes, but not the nickel, giving rise to the "green rot" that eventually destroys the thermo-
couple. During the fast cooling of NiCr-Ni thermocouples, that has been operating at temperatures
above 700 °C, certain states occur within the crystal structure (short-range order), which in Type
K elements can result in a change in thermoelectric voltage of up to 0.8 mV (K effect).
WIKA Operating Instructions Model TR10-L/TC10-L EEx d
Class A
-
60.11 ... 60.40
80.21 ... 80.41
88.14 ... 88.30
99.94 ... 100.06
107.72 ... 107.87
138.37 ... 138.64
157.16 ... 157.49
193.86 ... 194.33
211.78 ... 212.32
263.82 ... 264.53
-
-
Recommended max. operating temperature
1200 °C
800 °C
800 °C
400 °C
1200 °C
1600 °C
1600 °C
1700 °C
Class B
19.69 ... 20.80
59.93 ... 60.58
80.09 ... 80.52
88.04 ... 88.40
99.88 ... 100.12
107.64 ... 107.95
138.20 ... 138.81
156.93 ... 157.72
193.54 ... 194.66
211.41 ... 212.69
263.31 ... 265.04
280.04 ... 281.91
312.65 ... 314.77
GB
11