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8.2 SDI-12 measurements

The CS650 responds to SDI-12 commands

M1!

M2!

M3!

M4!

, and

Table 8-3

(p. 19)

shows the values returned for each of these commands.

Establish SDI-12 communications using the

SDI12Recorder()

CRBasic instruction. See

Data

logger wiring

(p. 11) for SDI-12 wiring details.

NOTE:
This section briefly describes using SDI-12 commands. Additional SDI-12 information is

available at

SDI-12 sensor support

(p. 41),

www.sdi-12.org

, or

www.youtube.com/user/CampbellScientific

Table 8-3: CS650 SDI-12 commands

SDI-12 command

(“a” is the sensor address)

Values returned

Units

aM!

1. Volumetric Water Content, q

2. Electrical Conductivity, s

3. Temperature

dS/m

°C

aM1!

1. Permittivity, e

2. Electrical Conductivity, s

3. Temperature

dS/m

°C

aM2!

1. Period, t

2. Voltage Ratio, a

3. Temperature

μs

°C

aM3!

1. Volumetric Water Content, q

2. Electrical Conductivity, s

3. Temperature

4. Permittivity, e

5. Period, t

6. Voltage Ratio, a

dS/m

°C

μs

CS650 and CS655 Water Content Reflectometers

Содержание CS650

Страница 2: ...onfiguration Utility 13 8 1 1 Using the A200 13 8 1 1 1 Driver installation 13 8 1 1 2 RS 232 wiring 13 8 1 1 3 Powering the sensor 14 8 1 1 4 Determining which COM port the A200 has been assigned 14...

Страница 3: ...n 29 8 4 5 Calculations 32 9 Maintenance and troubleshooting 32 10 References 34 Appendix A Importing Short Cut code into CRBasic Editor 35 Appendix B Example programs 36 B 1 CR1000X with one CS650 se...

Страница 4: ...D 3 References 47 Table of Contents iii...

Страница 5: ...rt see an older manual at www campbellsci com old manuals 2 Precautions l READ AND UNDERSTAND the Safety section at the back of this manual l Although the CS650 is rugged it should be handled as a pre...

Страница 6: ...e data logger model 3 In the Available Sensors and Devices box type CS650 You can also locate the sensor in the Sensors Meteorological Soil Moisture CS650 CS655 Water Content Reflectometer folder The...

Страница 7: ...ut Setup type the scan rate If you chose to measure the CS650 hourly rather than every scan this scan interval must be evenly divisible into an hour Type a meaningful table name and type the Data Outp...

Страница 8: ...ted to the data logger check the output of the sensor in the data display in LoggerNet RTDAQ or PC400 to make sure it is making reasonable measurements 5 Overview The CS650 measures volumetric water c...

Страница 9: ...The average travel time of the reflected wave multiplied by a scaling factor of 128 is called the period average Period average is reported in microseconds and is considered to be the raw output of a...

Страница 10: ...Scientific data loggers Alternatively use the orange wire to transmit and receive RS 232 The A200 USB to Serial Module allows RS 232 communications between a computer and the CS650 by means of Campbel...

Страница 11: ...al1 Electromagnetic compatibility View EU Declaration of Conformity documentation at www campbellsci com cs650 External RF sources can affect CS650 measurements CS650 circuitry should be located away...

Страница 12: ...amps per sensor 6 2 Operational specifications Table 6 2 p 8 provides the operational specifications Table 6 2 Relative dielectric permittivity specifications CS650 CS655 Relative dielectric permittiv...

Страница 13: ...C for typical soil temperatures 0 to 40 C when sensor body is buried in soil 0 5 C for full temperature range Precision 0 02 C Sensing volume 7800 cm3 3600 cm3 Sensing volume approximately 7 5 cm rad...

Страница 14: ...estimates soil water content The thermistor used to measure temperature is in contact with one of the stainless steel rods at the base of the epoxy sensor body Because of the low thermal conductivity...

Страница 15: ...ontent reflectometer SDI 12 data is transmitted to a CRBasic data logger odd numbered control or U terminal Wiring information for RS 232 communications is provided in RS 232 wiring p 13 Table 7 1 Wir...

Страница 16: ...and edited in CRBasic Editor A Short Cut tutorial is available in QuickStart p 2 If you wish to import Short Cut code into CRBasic Editor to create or add to a customized program follow the procedure...

Страница 17: ...ore plugging the A200 into the computer To download the A200 drivers go to www campbellsci com downloads a200 sensor interface usb driver and click Download Now 8 1 1 2 RS 232 wiring One end of the A2...

Страница 18: ...usly installed some of which may not be plugged in the A200 may be assigned a higher COM port number To check which COM port has been assigned to the A200 monitor the appearance of a new COM port in t...

Страница 19: ...CS650 operating system Settings that may be modified include User Name SDI 12 Address and RS 232 Baud Rate Attempts to change any of the other settings results in a Commit failed Unrecognized error c...

Страница 20: ...and no error checking After any changes to CS650 settings select Apply to write the changes to the CS650 operating system A configuration summary is then shown The summary may be printed or saved elec...

Страница 21: ...CS650 and CS655 Water Content Reflectometers 17...

Страница 22: ...update the operating system in the CS650 The operating system is available at www campbellsci com downloads The file to send has a filename extension of a43 such as CS65X Std 02 a43 Sending a new oper...

Страница 23: ...ble at SDI 12 sensor support p 41 www sdi 12 org or www youtube com user CampbellScientific Table 8 3 CS650 SDI 12 commands SDI 12 command a is the sensor address Values returned Units aM 1 Volumetric...

Страница 24: ...with a terminal emulator in SDI 12 transparent mode see SDI 12 sensor support p 41 8 2 1 M3 and M4 commands Typically the M4 command is used to report volumetric water content electrical conductivity...

Страница 25: ...culated permittivity is less than 80 of the permittivity limit A permittivity limit based on the bulk electrical conductivity EC reading is used to determine whether the bulk EC at saturation exceeds...

Страница 26: ...to supply power to CS650 4 Delay for 3 seconds for sensor to warm up 5 Send SDI 12 command s to CS650 6 Set switched 12 volt terminal low to remove power from CS650 7 Repeat steps 2 through 5 for eac...

Страница 27: ...0 6Ka 3 Research has shown that this equation works well in most mineral soils so a soil specific calibration of the CS650 sensor is usually not necessary For a soil specific calibration you can gener...

Страница 28: ...of different soils must be at the same water content The calibration equation in the CS650 operating system corrects the oscillation frequency for the effects of solution up to 3 dS m 1 for the CS650...

Страница 29: ...e 20 C reading over the range of 10 to 30 C and less than 2 of the 20 C reading over the range of 10 to 70 C The larger error is caused by the change in dielectric permittivity of soil with temperatur...

Страница 30: ...ater than 0 5 or bulk density greater than 1 55 g cm 3 may require a media specific calibration equation In these cases the user may develop a calibration equation to convert CS650 permittivity to vol...

Страница 31: ...tion equation p 26 Required equipment l CS650 connected to data logger programmed to measure permittivity l Cylindrical sampling devices to determine sample volume for bulk density such as copper tubi...

Страница 32: ...rods through the soil surface until the rods are completely surrounded by soil Avoid moving the rods from side to side because this can form air voids around the rods 4 Collect the sensor permittivit...

Страница 33: ...e replicate samples Three carefully handled samples provide good results 13 Calculate gravimetric water content from wet mass of sample mwet and dry mass of sample mdry For the bulk density the dry ma...

Страница 34: ...sensor is used provides the best on site soil specific calibration However intentionally changing water content in soil profiles is difficult Soil hydraulic properties are spatially variable Obtaining...

Страница 35: ...4643 93 requires heating in microwave for 3 minutes cooling in desiccator then weighing and repeating this process until mass is constant h Weigh the container holding the dry soil and subtract the co...

Страница 36: ...core sample during drying in an oven To obtain mwet subtract the cylinder empty mass and the container empty mass from the mass of the soil filled cylinder in the tray Remove all the soil from the cyl...

Страница 37: ...being powered Change sensor address or modify program so that they match Connect wire to correct control port or modify program to match wiring Make sure red wire is connected to 12V or SW12V and bla...

Страница 38: ...urface conductivity on bulk soil electrical conductivity Soil Sci Soc Am J 40 651 653 Rhoades J D N A Manteghi P J Shouse W J Alves 1989 Soil electrical conductivity and soil salinity New formulations...

Страница 39: ...itional refinement NOTE Once the file is edited with CRBasic Editor Short Cut can no longer be used to edit the program it created 2 To add the Short Cut wiring information into the new CRBasic progra...

Страница 40: ...or one sensor example program CR1000X CS650 12V Red C1 Green G Black orange clear CRBasic Example 1 CR1000X with one CS650 sensor Public CS650 6 Assign aliases to the public array Alias CS650 1 VWC Al...

Страница 41: ...in this example Table B 2 CR1000X wiring for two sensor example program CR1000X CS650 wiring same for both 12V Red C1 Green G Black orange clear CRBasic Example 2 CR1000X with two CS650 sensors on sa...

Страница 42: ...measure all 12 sensors is more than 36 seconds Alternately all of the red wires for the sensors could be connected to a bus separate from the multiplexer with the bus connected to 12V for continuous...

Страница 43: ...y 0 150 mSec LCount 1 SubScan 0 uSec 12 PulsePort C3 10000 Switch to next AM16 32 terminal SW12 SW12_1 1 Apply power to CS650 Delay 0 3 Sec Wait three seconds for sensor to warm up SDI12Recorder CS650...

Страница 44: ...ample mwet drying the sample to remove the water then weighing the dried soil mdry Volumetric water content v is the volume of liquid water per volume of soil Volume is the ratio of mass to density b...

Страница 45: ...e videos D 1 SDI 12 command basics SDI 12 commands have three components l Sensor address a a single character and the first character of the command Use the default address of zero 0 unless multiple...

Страница 46: ...ensor manufacturer but usually includes the sensor address SDI 12 version manufacturer s name and sensor model information Serial number or other sensor specific information may also be included aI al...

Страница 47: ...er Each device on a single terminal must have a unique address A sensor address is changed with command aAb where a is the current address and b is the new address For example to change an address fro...

Страница 48: ...logger before most commands A concurrent measurement command C is aborted when another valid command is sent to the sensor before the measurement time has elapsed D 1 8 Send data command aD0 aD9 The S...

Страница 49: ...not be used The terminal emulator is accessed by navigating to the Tools list in PC400 or the Datalogger list in the Connect screen of LoggerNet Watch videos sdi12 sensors transparent mode from our we...

Страница 50: ...til the data logger responds with the data logger CR1000X prompt 8 Type SDI12 and press Enter 9 At the Select SDI12 Port prompt type the number corresponding to the control port where the sensor is co...

Страница 51: ...ent address from the previous step and b is the new address Press Enter The sensor changes its address and responds with the new address In the following example the sensor address is changed from 0 t...

Страница 52: ...ther manufacturer s products that are resold by Campbell Scientific are warranted only to the limits extended by the original manufacturer Refer to www campbellsci com terms warranty for more informat...

Страница 53: ...ion or Repair Reference number contact your CAMPBELL SCIENTIFIC regional office Please write the issued number clearly on the outside of the shipping container and ship as directed For all returns the...

Страница 54: ...rohibit climbing by other persons Take reasonable precautions to secure tripod and tower sites from trespassers l Use only manufacturer recommended parts materials and tools Utility and Electrical l Y...

Страница 55: ...nfo campbellsci fr www campbellsci fr Germany Location Phone Email Website Bremen Germany 49 0 421 460974 0 info campbellsci de www campbellsci de India Location Phone Email Website New Delhi DL India...

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