Section 7. Installation
328
PRT Measurement Circuit Overview
Configuration
Features
Note
•
Voltage Excitation
Four-wire half-bridge (p. 330)
•
High accuracy over long leads
•
More input terminals: four per sensor
•
Slower: four differential sub
measurements per measurement
Best voltage excitation
configuration
Three-wire half-bridge (p. 334)
•
Good accuracy over long leads.
•
Fewer input terminals: two per sensor
•
Faster: two single-ended sub
measurements per measurement
Costs less to build
Four-wire full-bridge (p. 338)
•
High resolution response to change
•
More complicated to build
•
Two input terminals per sensor
•
Two differential sub measurements
per measurement
•
Best over short leads.
•
Best resolution since the
bridge balances at the
temperature-range midpoint.
•
Current excitation
Basic four-wire circuit
•
Minimizes errors due to voltage drop
with long leads.
•
Uses off-the-shelf PRTs
•
More tolerant of lower-grade wiring
•
Two input terminals per sensor
Simplest to use
Full-bridge circuit
•
Minimizes errors due to voltage drop
over long leads.
•
More tolerant of lower-grade wiring
•
Two input terminals per sensor
Best overall
7.7.17.2 General Procedure (PRT)
Following is a general procedure for using a PRT:
1.
Build circuit.
2.
Wire circuit to the CR6.
3.
Calculate excitation voltage or current.
4.
Calibrate PRT.
5.
Measure PRT and convert output to temperature.
Several procedures follow that step you through use of common resistive-bridge
configurations to measure a
100 Ω PRT (a.k.a, PT100). Use the following data to
help you understand the examples:
Procedure Data
•
Units used in examples: mV (millivolts), mA (milliamperes), and mΩ
(milliohms)
Содержание CR6 Series
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Страница 76: ...Section 5 Overview 76 FIGURE 20 Half Bridge Wiring Example Wind Vane Potentiometer ...
Страница 80: ...Section 5 Overview 80 FIGURE 23 Pulse Input Wiring Example Anemometer ...
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Страница 251: ...Section 7 Installation 251 FIGURE 46 Running Average Frequency Response FIGURE 47 Running Average Signal Attenuation ...
Страница 454: ...Section 8 Operation 454 FIGURE 104 Narrow Sweep High Noise ...
Страница 459: ...Section 8 Operation 459 FIGURE 106 Vibrating Wire Sensor Calibration Report ...
Страница 535: ...Section 8 Operation 535 8 11 2 Data Display FIGURE 121 CR1000KD Displaying Data ...
Страница 537: ...Section 8 Operation 537 FIGURE 123 CR1000KD Real Time Custom ...
Страница 538: ...Section 8 Operation 538 8 11 2 3 Final Storage Data FIGURE 124 CR1000KD Final Storage Data ...
Страница 539: ...Section 8 Operation 539 8 11 3 Run Stop Program FIGURE 125 CR1000KD Run Stop Program ...
Страница 541: ...Section 8 Operation 541 FIGURE 127 CR1000KD File Edit ...
Страница 542: ...Section 8 Operation 542 8 11 5 PCCard Memory Card Management FIGURE 128 CR1000KD PCCard Memory Card Management ...
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Страница 549: ...Section 9 Maintenance Details 549 FIGURE 133 Separate Back Shell from Module FIGURE 134 Disconnect Battery Connector ...
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Страница 610: ...Section 11 Glossary 610 FIGURE 137 Relationships of Accuracy Precision and Resolution ...
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