Section 7. Installation
335
Bridge Resistor Values (mΩ)
Rf
100000
Procedure
1. Build circuit
1
:
a. Use
FIGURE: PT100 BrHalf3W() Three-Wire Half-Bridge Schematic
(p.
as a template.
b. For Rf, choose a 1%, 10 ppm/°C, 10000000 mΩ (10 kΩ resistor).
2. Wire circuit to datalogger:
Use
FIGURE: PT100 BrHalf3W() Three-Wire Half-Bridge Schematic
(p. 334)
as the wiring diagram.
3. Calculate excitation voltage:
Use the following equation to calculate the best excitation voltage (VX) for
the measurement range of –40 to 60 °C. The equation reduces the absolute
result by 1% to allow for resistor inaccuracy:
VX
max
= VS
max
/ (RS
max
/ (Rf + RS
max
)) • 0.99
where,
VS
max
= 200 mV (maximum voltage in the
±
200
input range)
Rf = 10000000 mΩ
RS
max
= 123240 mΩ (PT00 at 60 °C)
2
so,
VX
max
= 1626420334066 mV
4. Calibrate the PT100:
If the PRT accuracy specification is good enough, and you trust it, assume
RS
0
= 100000 mΩ. Otherwise, do the following procedure:
a. Enter
CRBasic EXAMPLE: PT100 BrHalf3W() Three-Wire Half-Bridge
Calibration
(p. 337)
into the CR6. It is already programmed with the excitation
voltage from step 3.
b. Place the PRT in an ice bath (0 °C).
Summary of Contents for CR6 Series
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Page 76: ...Section 5 Overview 76 FIGURE 20 Half Bridge Wiring Example Wind Vane Potentiometer ...
Page 80: ...Section 5 Overview 80 FIGURE 23 Pulse Input Wiring Example Anemometer ...
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Page 454: ...Section 8 Operation 454 FIGURE 104 Narrow Sweep High Noise ...
Page 459: ...Section 8 Operation 459 FIGURE 106 Vibrating Wire Sensor Calibration Report ...
Page 535: ...Section 8 Operation 535 8 11 2 Data Display FIGURE 121 CR1000KD Displaying Data ...
Page 537: ...Section 8 Operation 537 FIGURE 123 CR1000KD Real Time Custom ...
Page 538: ...Section 8 Operation 538 8 11 2 3 Final Storage Data FIGURE 124 CR1000KD Final Storage Data ...
Page 539: ...Section 8 Operation 539 8 11 3 Run Stop Program FIGURE 125 CR1000KD Run Stop Program ...
Page 541: ...Section 8 Operation 541 FIGURE 127 CR1000KD File Edit ...
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Page 610: ...Section 11 Glossary 610 FIGURE 137 Relationships of Accuracy Precision and Resolution ...
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