Omega OM-USB-TEMP-AI, Руководство пользователя

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OM-USB-TEMP-AI User's Guide Specifications
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Thermistor measurement accuracy: T0x-T3x
Table 7. Thermistor measurement accuracy specifications, Ix+ = 10 µA. All specifications are (±)
Thermistor Sensor
temperature range Accuracy error
maximum
(°C)
Accuracy error
typical
(°C)
Tempco
(°C/°C)
-40 °C 0.001 0.0007 0.001
0 °C 0.021 0.008 0.001
50 °C 0.263 0.130 0.001
2252 _
120 °C 3.473 1.750 0.001
-35 °C 0.001 0.0006 0.001
0 °C 0.009 0.004 0.001
50 °C 0.115 0.049 0.001
5000 _
120 °C 1.535 0.658 0.001
-25 °C 0.001 0.0005 0.001
0 °C 0.005 0.002 0.001
50 °C 0.060 0.028 0.001
10000 _
120 °C 0.771 0.328 0.001
-10 °C 0.001 0.0005 0.001
0 °C 0.002 0.001 0.001
50 °C 0.019 0.009 0.001
30000 _
120 °C 0.267 0.128 0.001
Note 12:
Error shown does not include errors of the sensor itself. The sensor linearization is performed
using a Steinhart-Hart 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 OM-USB-TEMP-AI unit is between 15 °C and 35 °C. The
specification does not include lead resistance errors for 2-wire thermistor connections. Contact
your sensor supplier for details on the actual sensor error limitations. Total thermistor resistance
on any given channel pair must not exceed 180k ohms. Typical resistance values at various
temperatures for supported thermistors are shown in Table 8.
Table 8. Typical thermistor resistance measurement range
Temp 2252 _
thermistor 3000 _
thermistor 5 k_
thermistor 10 k_ thermistor 30 k_ thermistor
-40 °C 76 k_ 101 k_ 168 k_ 240 k_ (Note 13) 885 k_ (Note 13)
-35 °C 55 k_ 73 k_ 121 k_ 179 k_ 649 k_ (Note 13)
-30 °C 40 k_ 53 k_ 88 k_ 135 k_ 481 k_ (Note 13)
-25 °C 29 k_ 39 k_ 65 k_ 103 k_ 360 k_ (Note 13)
-20 °C 22 k_ 29 k_ 49 k_ 79 k_ 271 k_ (Note 13)
-15 °C 16 k_ 22 k_ 36 k_ 61 k_ 206 k_ (Note 13)
-10 °C 12 k_ 17 k_ 28 k_ 48 k_ 158 k_
-5 °C 9.5 k_ 13 k_ 21 k_ 37 k_ 122 k_
0 °C 7.4 k_ 9.8 k_ 16 k_ 29 k_ 95 k_
Note 13:
Resistance values greater than 180 k ohms cannot be measured by the OM-USB-TEMP-AI in the
thermistor mode. The 180 k ohm resistance limit includes the total resistance across the current
excitation (±Ix) pins, which is the sum of the thermistor resistance and the lead resistances.
Note 14:
For accurate three wire compensation, the individual lead resistances connected to the ±Ix pins
must be of equal ohmic value. To ensure this, use connection leads of equal lengths.