Accuracy; Thermocouple Measurement Accuracy: T0X To T3X - Omega OM-USB-TC-AI User Manual

OM-USB-TC-AI User's Guide

Accuracy

Thermocouple measurement accuracy: T0x to T3x

Table 4. Thermocouple accuracy specifications, including CJC measurement error. All specifications are (±)
Sensor Sensor temperature
Type range (°C)
–210
J
0
1200
–210
K
0
1372
–50
S
250
1768
–50
R
250
1768
B 250
700
1820
–200
E
0
1000
–200
T
0
400
–200
N
0
1300
Thermocouple measurement accuracy specifications include polynomial linearization, cold-junction
Note 5:
compensation and system noise. These specs are for one year, or 3000 operating hours, whichever
comes first, and for operation of the OM-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.
Thermocouples must be connected to the OM-USB-TC-AI such that they are floating with respect to
Note 6:
GND. The OM-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.
Accuracy error Accuracy error
maximum (°C)
Typical (°C)
2.028 0.707
0.835 0.278
0.783 0.288
2.137 0.762
0.842 0.280
0.931 0.389
1.225 0.435
0.554 0.195
0.480 0.157
1.301 0.458
0.549 0.190
0.400 0.134
2.193 2.185
0.822 0.819
0.469 0.468
1.976 0.684
0.954 0.321
0.653 0.240
2.082 0.744
0.870 0.290
0.568 0.208
2.197 0.760
0.848 0.283
0.653 0.245
19
Specifications
Tempco
(°C/°C)
0.031
0.035
0.021
0.019
0.001
0.030
0.035
0.028