Measurement Computing WLS-TEMP - Manual (Page 26)

WLS-TEMP Specifications
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RTD measurement accuracy
Table 6. RTD measurement accuracy specifications
RTD Sensor
Temperature (°C) Maximum Accuracy Error (°C)
I
x+
= 210 µA
Typical Accuracy Error (°C)
I
x+
= 210 µA
PT100, DIN, US or
ITS-90
–200 to –150 ±2.85 ±2.59
–150 to –100 ±1.24 ±0.97
–100 to 0 ±0.58 ±0.31
0 to 100 ±0.38 ±0.11
100 to 300 ±0.39 ±0.12
300 to 600 ±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
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 9: 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.
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 (°C) Maximum accuracy error (°C)
I
x+
= 10 µA
2252 Ω –40 to120 ±0.05
3000 Ω –40 to120 ±0.05
5000 Ω –35 to120 ±0.05
10000 Ω –25 to120 ±0.05
30000 Ω –10 to120 ±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
device 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 Ω. Typical
resistance values at various temperatures for supported thermistors are shown in Table 8.
Table 8. Typical thermistor resistance specifications
Temp
(°C) 2252 Ω
thermistor 3000 Ω
thermistor 5 kΩ
thermistor 10 kΩ
thermistor 30 kΩ
thermistor
–40 76 kΩ 101 kΩ 168 kΩ 240 kΩ (Note 12) 885 kΩ (Note 12)
–35 55 kΩ 73 kΩ 121 kΩ 179 kΩ 649 kΩ (Note 12)
–30 40 kΩ 53 kΩ 88 kΩ 135 kΩ 481 kΩ (Note 12)
–25 29 kΩ 39 kΩ 65 kΩ 103 kΩ 360 kΩ (Note 12)
–20 22 kΩ 29 kΩ 49 kΩ 79 kΩ 271 kΩ (Note 12)
–15 16 kΩ 22 kΩ 36 kΩ 61 kΩ 206 kΩ (Note 12)
–10 12 kΩ 17 kΩ 28 kΩ 48 kΩ 158 kΩ
–5 9.5 kΩ 13 kΩ 21 kΩ 37 kΩ 122 kΩ
0 7.4 kΩ 9.8 kΩ 16 kΩ 29 kΩ 95 kΩ