8 2561 HTPRT Module
This section explains the features and operation of the optional 2561 HTPRT
Module.
8.1 Description
The 2561 HTPRT Module is an add-on module that allows the 1560 to measure
temperature with high-temperature PRT sensors. It is capable of measuring
high-temperature with very high accuracy. It accepts four-wire sensors with
nominal resistances of 0.25Ω to 5Ω. It uses 3 or 5 mA excitation current to
minimize sensor self-heating. The excitation current alternates polarity to mini
-
mize the effects of thermoelectric offsets. Two sensors can be connected to the
2561 simultaneously and measured alternately.
8.2 Specifications
Resistance range
0to25
Ω
Resistance accuracy, one-year
1
0to2
Ω
2to25
Ω
0.0001
Ω
50 ppm of reading
Resistance accuracy, short-term
1, 2
0to2
Ω
2to25
Ω
0.00008
Ω
40 ppm of reading
Temperature accuracy (typical, not including sensor uncer-
tainty)
1
0°C
100°C
400°C
800°C
1200°C
±0.013°C
±0.018°C
±0.035°C
±0.060°C
±0.090°C
Temperature coefficient
1
2.5 ppm/°C
Excitation current 3, 5mA; 1 Hz
Maximum lead resistance
10
Ω
Sample time 2 seconds
Number of channels 2
Recommended operating temperature range
1
18 to 28°C (64 to 82°F)
Absolute operating temperature range 5 to 35°C (40 to 95°F)
Weight 2 lbs.
1
The accuracy specifications apply within the recommended operating temperature range. Accuracy limits
are increased by a factor of the temperature coefficient outside this range.
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8 2561 HTPRT Module
Description