Related Manuals for Campbell 253
Summary of Contents for Campbell 253
- Page 1 253 and 257 Soil Matric Potential Sensors Revision: 8/19 Copyright © 1993 – 2019 Campbell Scientific...
- Page 3 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 5 PLEASE READ FIRST 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...
- Page 7 • 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 9: Table Of Contents
B. Example Programs ..........B-1 Figures 5-1. 257 Soil Matric Potential Sensor with capacitor circuit and completion resistor installed in cable. Model 253 is the same, except that it does not have completion circuitry in the cable........9 7-1. 257 schematic ..................12 7-2. - Page 10 7-5. Conversion of Matric Potential to Other Units ........15 B-1. 107/257 Wiring for Example Program ..........B-1 B-2. Wiring for 253 Example ..............B-2 CRBasic Examples B-1. CR6 Program Measuring a 107 and 257 .......... B-1 B-2. CR1000X Program Measuring Five 107s and Five 253s ....B-3...
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Page 11: Introduction
Avoid installing in depressions where water will puddle after a rain storm. • Don’t place the 253 or 257 in high spots or near changes in slope unless • wanting to measure the variability created by such differences. -
Page 12: Quickstart
Short Cut is an easy way to program your data logger to measure the 253 or 257 and assign data logger wiring terminals. Short Cut is available as a download on www.campbellsci.eu. It is included in installations of LoggerNet, PC200W, PC400, or RTDAQ. - Page 13 253 and 257 Soil Matric Potential Sensors Click on the Wiring tab to see how the sensor is to be wired to the data logger. Click OK after wiring the sensor. In the Available Sensors and Devices box, type 257. You can also locate the sensor in the Sensors >...
- Page 14 253 and 257 Soil Matric Potential Sensors Click on the Wiring tab to see how the sensor is to be wired to the data logger. Click OK after wiring the sensor. In Output Setup, type the scan rate, meaningful table names, and the...
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Page 15: 253 Short Cut Programming
253 and 257 Soil Matric Potential Sensors Select the output options. Click Finish and save the program. Send the program to the data logger if the data logger is connected to the computer. 10. If the sensor is connected to the data logger, check the output of the sensor in LoggerNet, PC400, RTDAQ, or PC200W to make sure it is making reasonable measurements. - Page 16 253 and 257 Soil Matric Potential Sensors In the Available Sensors and Devices box, type 253. You can also locate the sensor in the Meteorological > Soil Moisture folder. Double click the 253 Soil Moisture Sensor. Select the number of sensors, resistance units, soil water potential units, and soil reference temperature.
- Page 17 253 and 257 Soil Matric Potential Sensors In Output Setup, type a scan rate. When using a multiplexer, Campbell Scientific recommends a scan rate that is at least 30 s. Also type meaningful table names and the Data Output Storage Interval. Click Next.
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Page 18: Overview
253 to be shorter. The cable length of each 253 only needs to cover the distance from the multiplexer to the point of measurement. Typical cable length for the 253 is 25 to 50 ft. -
Page 19: 257 Soil Matric Potential Sensor With Capacitor Circuit And Completion Resistor Installed In Cable. Model 253 Is The Same, Except That It Does Not Have Completion Circuitry In The Cable
The 253 and 257 consist of two concentric electrodes embedded in a reference granular matrix material. The granular matrix material is surrounded by a synthetic membrane for protection against deterioration. -
Page 20: Specifications
257 contains blocking capacitors in its cable that minimizes galvanic degradation and measurement errors due to ground loops • For the 253, the multiplexer connection prevents electrolysis from prematurely destroying the probe Compatible with Campbell Scientific CRBasic data loggers: CR6, •... -
Page 21: Wiring
253 and 257 Soil Matric Potential Sensors Insert the sensors in the sensor access hole. A length of 1/2 inch class 315 PVC pipe fits snugly over the sensor collar and can be used to push in the sensor. The PVC can be left in place with the wires threaded through the pipe and the open end taped shut (duct tape is adequate). -
Page 22: 253 Wiring
TABLE and FIGURE show the data logger-to-multiplexer connections for the 2 x 32 mode. TABLE B-2, Wiring for 253 Example , shows wiring (B-2) for the 4 x 16 mode. -
Page 23: 253 Wiring Example
253 and 257 Soil Matric Potential Sensors TABLE 7-3. Data Logger to AM16/32-series Multiplexer Wiring (2 x 32 Mode) Data Logger Connection Multiplexer Connection Terminal Terminal C (control terminal) C (control terminal) U configured for voltage , EX, VX (voltage... -
Page 24: Programming
7.3.1 BRHalf Instruction CRBasic data loggers use the BRHalf() instruction with the RevEx argument set to True to excite and measure the 253 and 257. The result of the BRHalf() instruction is the ratio of the measured voltage divided by the excitation voltage. -
Page 25: Calculations
Desired Unit Multiply Result By 0.001 0.01 Interpreting Results As a general guide, 253 and 257 measurements indicate soil matric potential as follows: 0 to –10 kPa = Saturated soil –10 to –20 kPa = Soil is adequately wet (except coarse sands, which are beginning to lose water). -
Page 26: Troubleshooting
253 and 257 Soil Matric Potential Sensors Troubleshooting NOTE All factory repairs and recalibrations require a returned material authorization (RMA) and completion of the “Declaration of Hazardous Material and Decontamination” form. Refer to Please Read First page at the beginning of this manual for more information. -
Page 27: 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 following the procedure in Section 4, . -
Page 29: Example Programs
Appendix B. Example Programs CRBasic Example measures the resistance (kΩ) of one 257 sensor with the data logger. A 107 temperature probe is measured first for temperature correction of the 257 reading. Voltage range codes for other CRBasic data loggers are shown in TABLE 7-4. Sensor wiring for this example is shown in TABLE B-1. - Page 30 In this example, a 107 temperature probe is buried at the same depth as a corresponding 253 sensor. Voltage range codes for other CRBasic data loggers are shown in TABLE 7-4. Sensor wiring is shown in TABLE B-2.
- Page 31 PortSet(C1,1) 'Turn AM16/32 Multiplexer On Delay(0,150,mSec) i = 1 SubScan (0,uSec,5) PulsePort(C2,10000) 'Soil temperature measurement Therm107(T107_C(i),1,1,VX1,0,60,1,0) '253 Soil Moisture Sensor measurements BrHalf(kOhms(i),1,mV200,2,VX2,1,200,true,0,60,1,0) 'Convert resistance ratios to kOhms kOhms(i) = kOhms(i)/(1-kOhms(i)) kOhms(i)=(100+(1.8*T107_C(i)+32)-69.8)/100*kOhms(i) i = i+1 NextSubScan PortSet(C1,0) 'Turn AM16/32 Multiplexer Off...
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