Measurement Computing USB-TEMP-AI - Manual (Page 22)

USB-TEMP-AI User's Guide Specifications
22
Sensor
Type Sensor temperature
range (°C) Accuracy error
maximum (°C) Accuracy error
Typical (°C)
Tempco
(°C/°C)
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 device between 15 °C and 35 °C. There is a CJC sensor on each
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 device such that they are floating with respect to GND (pins
9, 19, 22, 27, 30, 33, 36, 39, 49). The device 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.
Semiconductor sensor measurement accuracy: T0x-T3x
Table 5. Semiconductor sensor accuracy specifications
Sensor type Temperature Range Accuracy Error maximum
LM35, TMP35 or
equivalent –40 °C to 150 °C ±0.50 °C
Note 8: Error shown does not include errors of the sensor itself. These specifications are for one year while
operation of the device is between 15 °C and 35 °C. Contact your sensor supplier for details on the
actual sensor error limitations.
RTD measurement accuracy: T0x-T3x
Table 6. RTD measurement accuracy specifications, I
x+
= 210 µA. All specifications are (±).
RTD Sensor temperature
range (°C) Accuracy error (°C)
maximum Accuracy error (°C)
typical Tempco
(°C/°C)
PT100, DIN,
US or ITS-90
–200 2.913 2.784 0.001
–150 1.201 1.070 0.001
–100 0.482 0.349 0.001
0 0.261 0.124 0.001
100 0.269 0.127 0.001
300 0.287 0.136 0.001
600 0.318 0.150 0.001
Note 9: The error shown does not include errors of the sensor itself. The sensor linearization is performed
using a Callendar-Van Dusen linearization algorithm. The accuracy and tempco specifications include
the accuracy of the Callendar-Van Dusen linearization algorithm. These specifications are for one year
while operation of the device is between 15 °C and 35 °C. The specification does not include lead
resistance errors for 2-wire RTD connections. Please contact your sensor supplier for details on the
actual sensor error limitations.
Note 10: Resistance values greater than 660 Ω cannot be measured by the device in the RTD mode. The
660 Ω resistance limit includes the total resistance across the current excitation (±Ix) pins, which is the
sum of the RTD resistance and the lead resistances.