Related Manuals for Campbell 237
Summary of Contents for Campbell 237
- Page 1 Leaf Wetness Sensor Revision: 01/2021 Copyright © 1988 – 2021 Campbell Scientific CSL I.D - 506...
- Page 2 Quotations for repairs can be given on request. It is the policy of Campbell Scientific to protect the health of its employees and provide a safe working environment, in support of this policy a “Declaration of Hazardous Material and Decontamination”...
- Page 3 About this manual Please note that this manual was originally produced by Campbell Scientific Inc. primarily for the North American market. Some spellings, weights and measures may reflect this origin. Some useful conversion factors: Area: 1 in (square inch) = 645 mm Mass: 1 oz.
- Page 4 • Periodically (at least yearly) check electrical ground connections. WHILE EVERY ATTEMPT IS MADE TO EMBODY THE HIGHEST DEGREE OF SAFETY IN ALL CAMPBELL SCIENTIFIC PRODUCTS, THE CUSTOMER ASSUMES ALL RISK FROM ANY INJURY RESULTING FROM IMPROPER INSTALLATION, USE, OR MAINTENANCE OF TRIPODS, TOWERS, OR ATTACHMENTS TO TRIPODS AND TOWERS...
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Page 5: Table Of Contents
10. References ..............9 Appendices A. Importing Short Cut Code Into CRBasic Editor ... A-1 B. Example Programs ..........B-1 Figures 7-1. Example 237 Field Installation ............5 7-2. 237 Sensor Schematic ................5 Tables 7-1. Wire Colour, Function, and Datalogger Connection ......5... - Page 6 Table of Contents 7-2. Measurement Instructions, Parameters, Results ........7 9-1. Symptom/Causes ..................9 CRBasic Examples B-1. CR1000 Program Example............... B-1 B-2. CR200(X) Program Example ............B-1...
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Page 7: Introduction
QuickStart Short Cut is an easy way to program your datalogger to measure the 237 and assign datalogger wiring terminals. Short Cut is available as a download on www.campbellsci.eu. It is included in installations of LoggerNet, RTDAQ,... - Page 8 Double-click the datalogger model. Under the Available Sensors and Devices list, select the Sensors | Miscellaneous Sensors folder. Double-click 237 Leaf Wetness Sensor to move the selection to the Selected device window. The wet/dry transition point needs to be determined for each application and sensor (Section 8.2, ).
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Page 9: Overview
Droplets must touch two fingers simultaneously to change the sensor resistance. For this reason, the 237 is typically coated with flat latex paint, which spreads water droplets. The colour and type of paint affect sensor performance. Campbell Scientific supplies the sensor unpainted because individual modifications will vary with the application. -
Page 10: Installation
Droplets can be detected earlier in formation by application of a non-conductive spreader to the surface of the sensing grid. The spreader most commonly employed is flat latex paint. Campbell Scientific supplies only uncoated sensors since coating preferences vary between applications. NOTE Campbell Scientific has not researched, nor does it recommend, paint formulations. -
Page 11: Wiring To Datalogger
FIGURE 7-1. Example 237 Field Installation Wiring to Datalogger FIGURE is a circuit schematic of the 237. TABLE describes wiring to Campbell Scientific dataloggers. ⏚ FIGURE 7-2. 237 Sensor Schematic TABLE 7-1. Wire Colour, Function, and Datalogger Connection... -
Page 12: Datalogger Programming
7.4.1 Measurement of Vs / Vx The base measurement of the 237 sensor is Vs/Vx, where Vs is the voltage measured and Vx is the excitation voltage supplied by the datalogger. Vs/Vx is measured by the datalogger with the instructions and parameters listed in... -
Page 13: Calculating Sensor Resistance
Operation An exact range of measurements is impossible to give since the 237 is field calibrated. The sensor is not precise and the quality of water bridging the electrodes varies. As demonstrated in Appendix B, Example Programs (p. -
Page 14: Calculating Wet Time Fraction
237 Leaf Wetness Sensor Calculating Wet Time Fraction Fraction of time wet are common data derived from 237 measurements. Calculating time fraction requires a wetness threshold. Refer to Section 8.2, , for more information on determining the threshold. Calibration (p. 8) -
Page 15: Troubleshooting
Can. J. Plant Sci. 58:179-187. East, David (Ohio State University). 1994. Field Testing of Phone Accessible Multi-Channel Datalogger for Tomato IPM Programs. Unpublished. NOTE The citation of researcher does not imply the endorsement of Campbell Scientific products by any researcher or institution. -
Page 16: Importing Short Cut Code Into Crbasic Editor
Appendix A. Importing Short Cut Code Into CRBasic Editor Short Cut creates a .DEF file that contains wiring information and a program file that can be imported into the CRBasic Editor. By default, these files reside in the C:\campbellsci\SCWin folder. Import Short Cut program file and wiring information into CRBasic Editor: Create the Short Cut program. -
Page 17: Example Programs
Appendix B. Example Programs Each example program measures leaf wetness and outputs a sample resistance and a time fraction the sensor is wet. In these examples, the output interval is set to 60 minutes, so a time fraction wet of .33 is equivalent to 20 minutes during that hour. - Page 18 Appendix B. Example Programs 'Calculate Time Fraction Wet at top of each hour If IfTime (0,60,Min) Then 'Interval must match data table interval TimeFractionWet = ScanIntervalWet / ScanIntervalSum ScanIntervalWet = 0 ScanIntervalSum = 0 EndIf CallTable (Wetness) NextScan EndProg...
- Page 19 Campbell Scientific regional offices Australia France Thailand Location: Garbutt, QLD Australia Location: Vincennes, France Location: Bangkok, Thailand Phone: 61.7.4401.7700 Phone: 0033.0.1.56.45.15.20 Phone: 66.2.719.3399 Email: info@campbellsci.com.au Email: info@campbellsci.fr Email: info@campbellsci.asia Website: www.campbellsci.com.au Website: www.campbellsci.fr Website: www.campbellsci.asia Brazil Germany Location: São Paulo, SP Brazil...