Section 7. Installation
290
Calibrate PRT
Used:
X
CAL
= (1000*(V1
CAL
/VX)), where (1000*(V1
CAL
/VX)) is the output of
BrFull() with Mult
= 1,
Offset
= 0
X3
CAL
= (X
CAL
*0.001) + (R2/(R1+R2))
Related:
V1
CAL
= VX*((R3
CAL
/(R3
CAL
+R4)) – (R2/(R1+R2)))
Slope, Offset, and Xp
M = 0.001
B = (R2/(R1+R2))
Xp = ((1000*(V1/VX))*M+B
Rs/R0, K, and temperature
Rs/R0 =
–(R4/((R4*X3
CAL
)/(1–X3
CAL
)))*(Xp/(Xp – 1))
K = (Rs/R0)
–1
T = (SQRT(d * (R/R0) + e)
– a) / f (see PRT Calculation Standards for
coefficients)
or
T = g * K^4 + h * K^3 + I * K^2 + j * K (see PRT Calculation Standards for
coefficients)
Resistance of the PRT (R3):
R3 =
(R4 • X3)/(1 – X3)
X3 = (X / 1000) + (R2/(R1
+ R2))
Measurement resolution:
There is a change of approximately 4 mV from the output at 40 °C to the
output at 51 °C, or 400 µV / °C. With a resolution of 0.33 µV on the ±50
mV range, this means that the temperature resolution is 0.0009 °C.
7.7.17.6
Example: 100 Ω PRT in Four
-Wire Basic Circuit (PT100 / Basic
Resistance() )
This example shows the simplest PRT setup and how to measure multiple PRTs
from one U terminal set up for current excitationIX terminal.
Summary of Contents for CR3000 Micrologger
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Page 485: ...Section 8 Operation 485 8 11 2 Data Display FIGURE 110 Keyboard and Display Displaying Data ...
Page 487: ...Section 8 Operation 487 FIGURE 112 CR1000KD Real Time Custom ...
Page 491: ...Section 8 Operation 491 FIGURE 116 Keyboard and Display File Edit ...
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Page 564: ...Section 11 Glossary 564 FIGURE 126 Relationships of Accuracy Precision and Resolution ...
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