Accuracy, Thermocouple measurement accuracy: t0x to t3x – Measurement Computing USB-TC-AI User Manual
Page 17
USB-TC-AI User's Guide
Specifications
17
Accuracy
Thermocouple measurement accuracy: T0x to T3x
Table 4. Thermocouple accuracy specifications, including CJC measurement error. All specifications are (±)
Sensor
Type
Sensor temperature
range (°C)
Accuracy error
maximum (°C)
Accuracy error
Typical (°C)
Tempco
(°C/°C)
J
–210
2.028
0.707
0.031
0
0.835
0.278
1200
0.783
0.288
K
–210
2.137
0.762
0.035
0
0.842
0.280
1372
0.931
0.389
S
–50
1.225
0.435
0.021
250
0.554
0.195
1768
0.480
0.157
R
–50
1.301
0.458
0.019
250
0.549
0.190
1768
0.400
0.134
B
250
2.193
2.185
0.001
700
0.822
0.819
1820
0.469
0.468
E
–200
1.976
0.684
0.030
0
0.954
0.321
1000
0.653
0.240
T
–200
2.082
0.744
0.035
0
0.870
0.290
400
0.568
0.208
N
–200
2.197
0.760
0.028
0
0.848
0.283
1300
0.653
0.245
Note 5:
Thermocouple measurement accuracy specifications include polynomial linearization, cold-junction
compensation and system noise. These specs are for one year, or 3000 operating hours, whichever
comes first, and for operation of the USB-TC-AI between 15 °C and 35 °C. There is a CJC sensor on
the temperature sensor input side of the module. The accuracy listed above assumes the screw
terminals are at the same temperature as the CJC sensor. Errors shown do not include inherent
thermocouple error. Contact your thermocouple supplier for details on the actual thermocouple
accuracy error.
Note 6:
Thermocouples must be connected to the USB-TC-AI such that they are floating with respect to GND.
The USB-TC-AI GND pins are isolated from earth ground. You can connect thermocouple sensors to
voltages referenced to earth ground as long as the isolation between the GND pins and earth ground is
maintained.
Note 7:
When thermocouples are attached to conductive surfaces, the voltage differential between multiple
thermocouples must remain within ±1.4 V. For best results, we recommend using insulated or
ungrounded thermocouples when possible.