Section 8. Operation
386
8.1.8 Cabling Effects — Details
Related Topics:
•
Cabling Effects — Overview
(p. 76)
•
Cabling Effects — Details
(p. 386)
Sensor cabling can have significant effects on sensor response and accuracy. This
is usually only a concern with sensors acquired from manufacturers other than
Campbell Scientific. Campbell Scientific sensors are engineered for optimal
performance with factory-installed cables.
8.1.8.1 Analog Sensor Cabling
Cable length in analog sensors is most likely to affect the signal settling time. For
more information, see
Signal Settling Time
(p. 318).
8.1.8.2 Pulse Sensor Cabling
Because of the long interval between switch closures in tipping-bucket rain gages,
appreciable capacitance can build up between wires in long cables. A built-up
charge can cause arcing when the switch closes and so shorten switch life. As
shown in figure
Current-Limiting Resistor in a Rain Gage Circuit
(p. 386),
a 100 Ω
resistor is connected in series at the switch to prevent arcing. This resistor is
installed on all rain gages currently sold by Campbell Scientific.
FIGURE 92: Current-Limiting Resistor in a Rain Gage
Circuit
8.1.8.3 RS-232 Sensor Cabling
RS-232 sensor cable lengths should be limited to 50 feet.
8.1.8.4 SDI-12 Sensor Cabling
The SDI-12 standard allows cable lengths of up to 200 feet. Campbell Scientific
does not recommend SDI-12 sensor lead lengths greater than 200 feet; however,
longer lead lengths can sometimes be accommodated by increasing the wire gage
or powering the sensor with a second 12 Vdc power supply placed near the
sensor.
Summary of Contents for CR800 Series
Page 2: ......
Page 4: ......
Page 6: ......
Page 32: ......
Page 34: ......
Page 54: ......
Page 92: ......
Page 310: ......
Page 446: ...Section 8 Operation 446 8 11 2 Data Display FIGURE 100 CR1000KD Displaying Data ...
Page 448: ...Section 8 Operation 448 FIGURE 102 CR1000KD Real Time Custom ...
Page 449: ...Section 8 Operation 449 8 11 2 3 Final Storage Data FIGURE 103 CR1000KD Final Storage Data ...
Page 450: ...Section 8 Operation 450 8 11 3 Run Stop Program FIGURE 104 CR1000KD Run Stop Program ...
Page 452: ...Section 8 Operation 452 FIGURE 106 CR1000KD File Edit ...
Page 456: ......
Page 462: ......
Page 523: ...Section 11 Glossary 523 FIGURE 116 Relationships of Accuracy Precision and Resolution ...
Page 524: ......
Page 526: ......
Page 556: ......
Page 558: ......
Page 560: ......
Page 597: ......