Thermistor Measurement Accuracy; Throughput Rate To Pc - Measurement Computing USB-5200 Series User Manual

USB-5203 User's Guide

Thermistor measurement accuracy

The error shown in Table 7 below 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 operating the
device 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 kΩ (refer to Table 8 below).
Thermistor Temperature Range (°C)
2252 Ω
–40 to120
3000 Ω
–40 to120
5000 Ω
–35 to120
10000 Ω
–25 to120
30000 Ω
–10 to120
Typical resistance values at various temperatures for supported thermistors are shown in Table 8 below.
The device cannot measure resistance values greater than 180 kΩ in thermistor mode. The 180 kΩ resistance
limit includes the total resistance across the current excitation (Ix+/Ix–) pins, which is the sum of the thermistor
resistance and the lead resistances.
For accurate three-wire compensation, the individual lead resistances connected to the Ix+/Ix– pins must be of
equal value.
2252 Ω
Temp
(°C) thermistor
76 kΩ
–40
55 kΩ
–35
40 kΩ
–30
29 kΩ
–25
22 kΩ
–20
16 kΩ
–15
12 kΩ
–10
9.5 kΩ
–5
7.4 kΩ
0

Throughput rate to PC

The analog inputs are configured to run continuously. Each channel is sampled twice per second. The maximum
latency between when a sample is acquired and the temperature data is provided by the USB unit is
approximately 0.5 seconds.
Maximum throughput to a CompactFlash® memory card is 1 S/s per channel.
Table 7. Thermistor measurement accuracy specifications
Table 8. Typical thermistor resistance specifications
3000 Ω thermistor
101 kΩ
73 kΩ
53 kΩ
39 kΩ
29 kΩ
22 kΩ
17 kΩ
13 kΩ
9.8 kΩ
Maximum Accuracy Error (°C)
Ix+ = 10 µA
±0.05
±0.05
±0.05
±0.05
±0.05
5 kΩ thermistor 10 kΩ thermistor
168 kΩ 240 kΩ
121 kΩ 179 kΩ
88 kΩ 135 kΩ
65 kΩ 103 kΩ
49 kΩ 79 kΩ
36 kΩ 61 kΩ
28 kΩ 48 kΩ
21 kΩ 37 kΩ
16 kΩ 29 kΩ
25
Specifications
30 kΩ thermistor
885 kΩ
649 kΩ
481 kΩ
360 kΩ
271 kΩ
206 kΩ
158 kΩ
122 kΩ
95 kΩ