USB-TEMP User's Guide
Specifications
5-3
Accuracy
Thermocouple measurement accuracy
Table 5-4. Thermocouple accuracy specifications, including CJC measurement error
Sensor Type
Maximum error
Typical error
Temperature range
J
±0.575 °C
±0.279 °C
-210 to 1200 °C
K
±0.629 °C
±0.309 °C
-200 to 1372 °C
±1.159 °C
±0.991 °C
-50 to 1768.1 °C
S
±0.806 °C
±0.634 °C
250 to 1768.1 °C
±1.142 °C
±0.974 °C
-50 to 1768.1 °C
R
±0.767 °C
±0.619 °C
250 to 1768.1 °C
±1.520 °C
±1.242 °C
250 to 1820 °C
B
±0.912 °C
±0.698 °C
700 to 1820 °C
E
±0.553 °C
±0.263 °C
-200 to 1000 °C
±0.641 °C
±0.347 °C
-200 to 600 °C
T
±0.529 °C
±0.281 °C
0 to 600 °C
±0.738 °C
±0.420 °C
-200 to 1300 °C
N
±0.596 °C
±0.318 °C
0 to 1300 °C
Note 4:
Thermocouple measurement accuracy specifications include 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-TEMP between 15 °C and 35 °C.
For measurements outside this range, add ±0.5 degree to the maximum error shown.
There are CJC sensors on each 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. Please contact your thermocouple supplier for
details on the actual thermocouple error.
Note 5:
Thermocouples must be connected to the USB-TEMP such that they are floating with
respect to GND (pins 9, 19, 28, 38). The USB-TEMP GND pins are isolated from earth
ground, so connecting thermocouple sensors to voltages referenced to earth ground is
permissible as long as the isolation between the GND pins and earth ground is
maintained.
Note 6:
When thermocouples are attached to conductive surfaces, the voltage differential between
multiple thermocouples must remain within ±1.4V. For best results we recommend the
use of insulated or ungrounded thermocouples when possible.
Semiconductor sensor measurement accuracy
Table 5-5. Semiconductor sensor accuracy specifications
Sensor Type
Temperature Range (
°C)
Maximum Accuracy Error
TMP36 or equivalent
-40 to 150
°C
±0.50
°C
Note 7:
Error shown does not include errors of the sensor itself. These specs are for one year
while operation of the USB-TEMP unit is between 15 °C and 35 °C. Please contact your
sensor supplier for details on the actual sensor error limitations.