7Tutorial
278 Keysight 34970A/34972A User’s Guide
Temperature Measurements
A temperature transducer measurement is typically either a resistance or voltage
measurement converted to an equivalent temperature by software conversion
routines inside the instrument. The mathematical conversion is based on specific
properties of the various transducers. The mathematical conversion accuracy (not
including the transducer accuracy) for each transducer type is shown below.
Errors associated with temperature measurements include all of those listed for
DC voltage and resistance measurements elsewhere in this chapter. The largest
source of error in temperature measurements is generally the transducer itself.
Your measurement requirements will help you to determine which temperature
transducer type to use. Each transducer type has a particular temperature range,
accuracy, and cost. The table below summarizes some typical specifications for
each transducer type. Use this information to help select the transducer for your
application. The transducer manufacturers can provide you with exact
specifications for a particular transducer.
.
Transducer Conversion Accuracy
Thermocouple
RTD
Thermistor
0.05°C
0.02°C
0.05°C
Parameter Thermocouple RTD Thermistor
Temperature Range
Measurement Type
Transducer Sensitivity
Probe Accuracy
Cost (U.S. Dollars)
Durability
-210°C to 1820°C
Voltage
6 μV/°C to 60 μV/°C
0.5°C to 5°C
$1 / foot
Rugged
-200°C to 850°C
2- or 4-Wire Ohms
≈ R
0
x 0.004°C
0.01°C to 0.1°C
$20 to $100 each
Fragile
-80°C to 150°C
2- or 4-Wire Ohms
≈ 400Ω /°C
0.1°C to 1°C
$10 to $100 each
Fragile
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