Owner's manual

OM-USB-TEMP User's Guide Specifications
23
RTD measurement accuracy
Table 6. RTD measurement accuracy specifications
RTD Sensor
Temperature
Maximum Accuracy Error (°C)
Ix+ = 210 µA
Typical Accuracy Error (°C)
Ix+ = 210 µA
-200°C to -150°C ±2.85 ±2.59
-150°C to -100°C ±1.24 ±0.97
-100°C to 0°C ±0.58 ±0.31
0°C to 100°C ±0.38 ±0.11
100°C to 300°C ±0.39 ±0.12
PT100, DIN, US or
ITS-90
300°C to 600°C ±0.40 ±0.12
Note 8: Error shown does not include errors of the sensor itself. The sensor linearization is performed
using a Callendar-Van Dusen linearization algorithm. These specs are for one year while
operation of the OM-USB-TEMP unit 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 9: Resistance values greater than 660 ohms cannot be measured by the OM-USB-TEMP in the RTD
mode. The 660 ohm resistance limit includes the total resistance across the current excitation
(±Ix) pins, which is the sum of the RTD resistance and the lead resistances.
Note 10: For accurate three wire compensation, the individual lead resistances connected to the ±Ix pins
must be of equal value.
Thermistor measurement accuracy
Table 7. Thermistor measurement accuracy specifications
Thermistor
Temperature Range Maximum Accuracy Error (°C)
Ix+ = 10 µA
2252 _ -40 to120 °C ±0.05
3000 _ -40 to120 °C ±0.05
5000 _ -35 to120 °C ±0.05
10000 _ -25 to120 °C ±0.05
30000 _ -10 to120 °C ±0.05
Note 11: Error shown does not include errors of the sensor itself. The sensor linearization is performed
using a Steinhart-Hart linearization algorithm. These specs are for one year while operation of the
OM-USB-TEMP unit is between 15 °C and 35 °C. The specification does not include lead
resistance errors for 2-wire thermistor connections. Please contact your sensor supplier for details
on the actual sensor error limitations. Total thermistor resistance on any given channel pair must
not exceed 180 k ohms. Typical resistance values at various temperatures for supported
thermistors are shown in Table 8.
Table 8. Typical thermistor resistance specifications
Temp 2252 Ω
thermistor
3000 Ω
thermistor
5 kΩ
thermistor
10 kΩ thermistor 30 kΩ thermistor
-40 °C 76 kΩ 101 kΩ 168 kΩ 240 kΩ (Note 12) 885 kΩ (Note 12)
-35 °C 55 kΩ 73 kΩ 121 kΩ 179 kΩ 649 kΩ (Note 12)
-30 °C 40 kΩ 53 kΩ 88 kΩ 135 kΩ 481 kΩ (Note 12)
-25 °C 29 kΩ 39 kΩ 65 kΩ 103 kΩ 360 kΩ (Note 12)
-20 °C 22 kΩ 29 kΩ 49 kΩ 79 kΩ 271 kΩ (Note 12)
-15 °C 16 kΩ 22 kΩ 36 kΩ 61 kΩ 206 kΩ (Note 12)
-10 °C 12 kΩ 17 kΩ 28 kΩ 48 kΩ 158 kΩ
-5 °C 9.5 kΩ 13 kΩ 21 kΩ 37 kΩ 122 kΩ
0 °C 7.4 kΩ 9.8 kΩ 16 kΩ 29 kΩ 95 kΩ