Section 7. Installation
296
7.7.17.7
Example: 100 Ω PRT in Four
-Wire Full Bridge with Current
Excitation (PT100 / Full-Bridge Resistance() )
FIGURE 72: PT100 Resistance() Four-Wire Full-Bridge Schematic
Procedure Information
Four-Wire Half-Bridge Equations for PRT Example
X = V1 / IX
X = ((R3 • (R1 + R2))
– (R2 • (R3 + R4))) / (R1 + R2 + R3 + R4)
R3 = ((
–R2 • R4) – (X • (R1 + R2 + R4))) / (X – R1)
RB = X / ((R3 / (R3 + R4))
– (R2 / (R1 + R2)))
Definitions:
•
X is the output of the Resistance() equation
•
V1 is the voltage output of the bridge at terminals U3 and U4 (this value
is used only internally in the CR3000).
•
IX is the magnitude of the current (I) excitation.
•
R1, R2, R4 are resistor values in the bridge.
•
R3 is the resistance of the PRT.
•
RB is the resistance of the whole bridge as measured between the IX
excitation line and the
ground line.
Bridge Resistor Values (mΩ)
R1
R2
R4
5000000
100000
5000000
Содержание CR3000 Micrologger
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Страница 200: ...Section 7 Installation 200 FIGURE 42 Running Average Frequency Response FIGURE 43 Running Average Signal Attenuation ...
Страница 485: ...Section 8 Operation 485 8 11 2 Data Display FIGURE 110 Keyboard and Display Displaying Data ...
Страница 487: ...Section 8 Operation 487 FIGURE 112 CR1000KD Real Time Custom ...
Страница 488: ...Section 8 Operation 488 8 11 2 3 Final Storage Data FIGURE 113 Keyboard and Display Final Storage Data ...
Страница 489: ...Section 8 Operation 489 8 11 3 Run Stop Program FIGURE 114 Keyboard and Display Run Stop Program ...
Страница 491: ...Section 8 Operation 491 FIGURE 116 Keyboard and Display File Edit ...
Страница 495: ...Section 8 Operation 495 Low power standby whenever possible Low power bus sets bus and modules to low power ...
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