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Campbell TDR100 Instruction Manual

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Manual is about: REFLECTOMETER

Summary of TDR100

  • Page 1

    Tdr100 revision: 2/10 c o p y r i g h t © 2 0 0 0 - 2 0 1 0 c a m p b e l l s c i e n t i f i c , i n c ..

  • Page 2: Warranty and Assistance

    Warranty and assistance the tdr100 is warranted by campbell scientific, inc. To be free from defects in materials and workmanship under normal use and service for twelve (12) months from date of shipment unless specified otherwise. Batteries have no warranty. Campbell scientific, inc.'s obligation u...

  • Page 3: Tdr100 Table of Contents

    Tdr100 table of contents pdf viewers note: these page numbers refer to the printed version of this document. Use the adobe acrobat® bookmarks tab for links to specific sections. 1. Introduction ..................................................................1 1.1 tdr100 packing list .................

  • Page 4

    Tdr100 table of contents 5.8 soil probes ............................................................................................. 17 5.8.1 determining probe constant, kp, using pctdr......................... 18 6. Datalogger instructions for tdr measurements ....18 6.1 cr800, cr850, cr1000, or ...

  • Page 5

    Tdr100 table of contents 11. References ...............................................................51 figures 3-1 waveform of a cs610 in water................................................................5 3-2 waveform of cs610 in water after changing start and length parameters to display rel...

  • Page 6

    Tdr100 table of contents iv.

  • Page 7: Tdr100

    Tdr100 1. Introduction this document presents operating instructions for the tdr100 and associated equipment and discusses time domain reflectometry (tdr) principles. Section 3 (getting started with tdr100 using pctdr) describes a simple start-up configuration to quickly and easily display tdr probe...

  • Page 8: 2.  System Specifications

    Tdr100 2. System specifications 2.1 general see the cr10x, cr23x, cr800/cr850, cr1000, or cr3000 datalogger manuals for datalogger specifications. 2.2 power consumption 2.2.1 tdr100 • the current demand for the tdr100 during measurement is 270 milliamps. • when the tdr100 is controlled by a datalogg...

  • Page 9

    Tdr100 waveform averaging 1 to 128 electrostatic discharge protection internal clamping power supply unregulated 12 volt (9.6 v to 16 v), 300 milliamps maximum temperature range -40 °c to 55°c dimensions 210mm x 110mm x 55 mm weight 700 g 2.4. Electromagnetic compatibility the tdr100 is Œ compliant ...

  • Page 10

    Tdr100 port 1 is the default setting and can be changed in pctdr menu settings/communications. The baud rate is factory set to 57600. 3. Connect 12 volt power to tdr100 12 volt power to the tdr100 is connected using terminals +12v and ground on the panel 5-terminal connector. An external power suppl...

  • Page 11

    Tdr100 figure 3-1. Waveform of a cs610 in water. Changing the waveform start value to 5.7 m and the waveform length to 5 m gives the waveform displayed in figure 3-2. 5.

  • Page 12: 4.  Pctdr Software

    Tdr100 figure 3-2. Waveform of cs610 in water after changing start and length parameters to display relevant portion of reflected signal. 3.2 pctdr help information on pctdr is available from the help menu or by pressing f1. Using f1 gives specific help associated with the position of the cursor or ...

  • Page 13

    Tdr100 when the tdr100 is connected to a cr23x or cr1000 datalogger using control ports 1-3 for sdm control and sdmx50 multiplexers are also connected, an instruction must be used in the datalogger program to properly configure the control ports. If this is not done, pctdr will not control the multi...

  • Page 14

    Tdr100 4.3 menu selections 4.3.1 file menu save configuration/load configuration - save and reload configuration of user-selectable parameters. Saves configuration as .Wfd file. Save ascii waveform - save displayed waveform as .Dat file. Save mux setup/load mux setup - save and reload multiplexer se...

  • Page 15

    Tdr100 4.4.2 waveform average - sets the number of measurements averaged at a given distance from the tdr100. A value of 4 is recommended. Higher values can be used when noise is present. Averaging is useful when noise from power sources or when noise of random nature is superimposed on the reflecti...

  • Page 16

    Tdr100 figure 4-1. Pctdr waveform for cs610 in water. The algorithm will use the length of the waveform set by the waveform length. After finding the probe beginning, the algorithm searches over the remaining waveform for the end of the probe. The length must be large enough to display a short dista...

  • Page 17

    Tdr100 ( ) l l w v = ⋅ + + − θ max . . 0176 0114 2 with l the actual probe rod length, and, θ v-max the maximum expected volumetric water content. Two m is added for the .5 m before the probe and some distance after the probe end. For example, using a cs610 with 0.3 m probe rod length in a soil with...

  • Page 18

    Tdr100 5.3 tdr100 the tdr100 contains the pulse generator for the signal applied to a tdr probe. The tdr100 also digitizes the reflection and applies numerical algorithms for measuring volumetric water content or electrical conductivity. The tdr100 communicates with the datalogger using sdm protocol...

  • Page 19

    Tdr100 5.5 power supply the system operates on 12 v power. A user supplied deep cycle 12 v lead acid battery is commonly used in remote installations. Two terminal strip adapters for the battery posts are provided with the enctdr100 (see figure 5-3). These terminal strips will mount to wing nut batt...

  • Page 20

    Tdr100 components in the enclosure. A short run of heavy gage (10 awg or heavier) wire should be connected from the enclosure lug to earth ground. The ground lug on peripheral sdmx50 multiplexer enclosures should only be used if the multiplexer is close enough to conveniently use the same ground poi...

  • Page 21

    Tdr100 figure 5-4. Location of address jumpers on sdmx50 table 5-1. Sdm addressing for early sn sdmx50s and edlog dataloggers base 10 number instruction 119 address (base4) tdr100 thumbwheel switch level 1 sdmx50 mux (tdr100+1) msd lsd level 2 sdmx50 muxs (tdr100+2) msd lsd level 3 sdmx50 muxs (tdr1...

  • Page 22

    Tdr100 5.6.2 sdm cable and cable length considerations a 5-conductor cable with shield and drain is used for interconnection of sdm devices. The 5 conductors are used for 12 volt power, ground and the 3 sdm lines. A cable assembly (pn13776) is provided with the tdr100 and the enctdr100. This assembl...

  • Page 23

    Tdr100 se diff g g h l 1 2 1 ag h l ag h l ag e1 ag e2 g 3 4 2 5 6 3 se diff g g h l 7 8 4 ag h l ag h l ag e3 ag g g 9 10 5 11 12 6 p1 g p2 g c8 c7 c6 c5 c4 c3 c2 c1 g 12v 12v sdm 5v 5v g g sw 12v sw 12v ctrl logan, utah g 12v g 12v power in cr10x wiring panel made in usa wiring panel no. Earth gro...

  • Page 24

    Tdr100 campbell scientific tdr probes cs605 cs610 general description 3-rod probe no balun required stainless steel rods 3-rod probe no balun required stainless steel rods dimensions rods: 30 cm length 0.476 cm diameter probe head: cable-to-rod 10.8 cm width 7.0 cm thickness 1.9 cm rods: 30 cm lengt...

  • Page 25

    Tdr100 sdmaddress: the sdmaddress parameter defines the address of the tdr100 with which to communicate. Valid sdm addresses are 0 through 14. Address 15 is reserved for the sdmtrigger instruction. If the reps parameter is greater than 1, the datalogger will increment the sdm address for each subseq...

  • Page 26

    Tdr100 length is used by the analysis algorithm to begin searching for the tdr probe. If a 1 or 2 is entered for the option parameter, cable length is the distance to the start of the collected waveform. The value used for cablelength is best determined using pctdr100 with the vp = 1.0. Adjust the c...

  • Page 27

    Tdr100 waveform averaging 4: fp 1 - 128 number of reflections averaged by the tdr100. V p 5: fp .1 - 1 relative propagation velocity points 6: fp 20- 2048 number of points in waveform cable length (meters) 7: fp 0 - 2100 distance for tdr100 corresponding with beginning of waveform window length (met...

  • Page 28

    Tdr100 6.3.2.2 enter 1: collect waveform the digitized reflection waveform can be collected from the tdr100 by the datalogger in ascii format. Datalogger input storage must be manually allocated for the waveform data points using “block allocation” in edlog datalogger software. The waveform is colle...

  • Page 29

    Tdr100 8 8 consecutive probes are read; the probes are connected to channels 1, 2, 3, 4, 5, 6, 7, and 8 of the level 1 multiplexer. Example 2 an entry of 3624: entry description 3 channel 3 is specified for the level 1 multiplexer. 6 channel 6 is specified for the level 2 multiplexer. 2 channel 2 is...

  • Page 30

    Tdr100 beginning of the probe can be read from the x-axis. Subtract 0.5 meters from the beginning distance and use that value in parameter 7 of datalogger instruction 119. It is important that the v p used during determination of value for cable length be the same v p used during subsequent measurem...

  • Page 31

    Tdr100 table 6-1. Reflection waveform array header elements. Description of array header elements 1 averaging 2 propagation velocity 3 number of data points 4 cable length 5 window length 6 probe rod length 7 probe offset 8 multiplier 9 offset 6.3.12 parameter 12: multiplier multiplication factor ap...

  • Page 32: 7.  Tdr Principles

    Tdr100 the probe constant (k p ) is easily determined using pctdr or can be determined through calibration. The probe rods are immersed in solutions of known electrical conductivity and values of 1 1 1 z c − + ρ ρ collected by the datalogger. A linear regression of known electrical conductivity to t...

  • Page 33

    Tdr100 the relationship between dielectric constant and volumetric water content has been described by, among others, topp et al. (1980) and ledieu et al. (1986) in an empirical fashion using both polynomial and linear forms. These expressions are presented here since it has been shown in numerous r...

  • Page 34

    Tdr100 8. Cable length and soil electrical conductivity effect on water content determination 8.1 cable length effect on water content measurement the determination of water content using the tdr system relies on the evaluation of a pulse reflection from the tdr probe. The pulse generated by the tdr...

  • Page 35

    Tdr100 cable lengths will be maintained as long as soil electrical conductivity does not prevent a reflection from the end of the probe rods. This is discussed later in this section. Minimizing cable lengths should always be considered in the design of a measurement system using tdr. If long cable l...

  • Page 36

    Tdr100 water content = 18% water content = 37% figure 8-3. Waveforms collected in a sandy loam using cs610 probe with rg8 connecting cable. Volumetric water content values are 10, 18, 26, 30 and 37%. Solution electrical conductivity is 10.2 ds m -1 . The combined effect of long cable runs and high s...

  • Page 37

    Tdr100 9.2.1.1 waveform evaluation figure 9-1 shows a typical waveform and identifies key points. The waveform before point 1 is the section of coaxial cable near the probe head with point 1 the transition from the 50 ohms of the cable to the impedance of the probe. The change in reflection coeffici...

  • Page 38

    Tdr100 9.2.2 algorithm parameter adjustment for special conditions the standard settings for the apparent length algorithm work well for nearly all applications. For special cases of very long cables or some probes that are not manufactured by campbell scientific an algorithm parameter change can im...

  • Page 39

    Tdr100 9.3 algorithm for calculation of bulk electrical conductivity 9.3.1 algorithm description section 7, tdr principles, presents the equation and method used by the tdr100 to calculate bulk electrical conductivity. The electrical conductivity calculation uses waveform values for the region immed...

  • Page 40

    Tdr100 to view the current parameter values type gecp at the > prompt. The values of the 4 parameters are returned. The default values for the threshold equation are: a = 0 b = 1 c = 2 therefore the default threshold is the mean plus twice the standard deviation of the values in the 10-point window ...

  • Page 41: 10.  Programming Examples

    Tdr100 10. Programming examples 10.1 cr1000 program example example 1, measure and record; analog measurements, volumetric water content, and capture tdr probe waveforms equipment wiring cr1000 tdr100 sdmx50 sw12 +12 v 12 v g g g c1 c1 c1 c2 c2 c2 c3 c3 c3 sensor wiring tdr100 sdmx50 tdr probe* coax...

  • Page 42

    Tdr100 'cr1000 series datalogger 'program: c:\mydoc\cr1000\cr1000-testing\tdr&sdm&f1&wave_cr1k.Cr1 'date: 10-27-04 'measure and record analog measurements, volumetric water content, & store waveforms ' 'declare public & dim variables ------------------------------------ public batt_volt public panel...

  • Page 43

    Tdr100 'main program --------------------------------------------------- beginprog sdmspeed (50) 'fix tdr100 to cr1k communication timing ' scan (5,sec,0,0) 'scan instructions every 5 sec battery (batt_volt) paneltemp (panel_temp,250) calltable dat15min ' 'set flag 1 high every 120 minutes (note: us...

  • Page 44

    Tdr100 ' muxchan=3001 tdr100 (wavept(),0,1,3001,4,1.0,251,9.5,5.0,0.3,0.085,1,0) calltable tdr_wave() ' muxchan=4001 tdr100 (wavept(),0,1,4001,4,1.0,251,9.5,5.0,0.3,0.085,1,0) calltable tdr_wave() ' muxchan=5001 tdr100 (wavept(),0,1,5001,4,1.0,251,9.5,5.0,0.3,0.085,1,0) calltable tdr_wave() ' muxcha...

  • Page 45

    Tdr100 ;{cr10x} ; ;program name = t100ex#1 ; *table 1 program 01: 60 execution interval (seconds) ;measure the datalogger power supply voltage: 1: batt voltage (p10) 1: 1 loc [ bat_volt ] ;measure the internal temperature of the datalogger: 2: internal temperature (p17) 1: 2 loc [ dl_temp ] ;set por...

  • Page 46

    Tdr100 ;output a time stamp; year, day, and hour/minute: 7: real time (p77) 1: 1220 year,day,hour/minute (midnight = 2400) ;output the minimum battery voltage: 8: minimum (p74) 1: 1 reps 2: 0 value only 3: 1 loc [ bat_volt ] ;output the average datalogger temperature and water content 9: average (p7...

  • Page 47

    Tdr100 1: if flag/port (p91) 1: 21 do if flag 1 is low 2: 0 go to end of program table ;measure the datalogger power supply voltage: 2: batt voltage (p10) 1: 1 loc [ bat_volt ] ;measure the internal temperature of the datalogger: 3: internal temperature (p17) 1: 2 loc [ dl_temp ] ;set port 5 high to...

  • Page 48

    Tdr100 ;apply topp's 3rd order polynomial: 8: polynomial (p55) 1: 1 reps 2: 4 x loc [ wc_ch3 ] 3: 4 f(x) loc [ wc_ch3 ] 4: -0.053 c0 5: .292 c1 6: -0.055 c2 7: 0.0043 c3 8: 0.0 c4 9: 0.0 c5 ;measure electrical conductivity on the same cs610 tdr probe connected to channel 3. 9: tdr100 measurement (p1...

  • Page 49

    Tdr100 ;turn off the switched 12v to power off the tdr100: 11: do (p86) 1: 55 set port 5 low ;set the output flag to output data each time measurements are made: 12: do (p86) 1: 10 set output flag high (flag 0) ;output a time stamp; year, day, and hour/minute: 13: real time (p77) 1: 1220 year,day,ho...

  • Page 50

    Tdr100 example 3, measure and record; volumetric water content and analog measurements eight cs605 or cs610 probes are connected to channel #1 through #8 of a level #1 sdmx50 multiplexer. A cable length value of 10 meters was determined using pctdr. The la/l value is converted to volumetric water co...

  • Page 51

    Tdr100 4: beginning of loop (p87) 1: 0 delay 2: 8 loop count ;square la/l to convert to dielectric constant: ;note: the user must manually allocate 8 input locations "wc_1" through wc_8". 5: z=x*y (p36) 1: 1 -- x loc [ lal_1 ] 2: 1 -- y loc [ lal_1 ] 3: 11 -- z loc [ wc_1 ] ;multiply the dielectric ...

  • Page 52

    Tdr100 *table 2 program 02: 0.0000 execution interval (seconds) *table 3 subroutines end program example 4, measure and record; analog measurements and volumetric water content in this example analog measurements are made every 5 minutes and tdr100 measurements are made every 60 minutes. Twenty-nine...

  • Page 53

    Tdr100 ;{cr10x} ;program = t100ex#4 *table 1 program 01: 300 execution interval (seconds) ;every 5 minutes (300 second execution interval) ;measure the datalogger power supply voltage: 1: batt voltage (p10) 1: 1 loc [ bat_volt ] ;measure the internal temperature of the datalogger: 2: internal temper...

  • Page 54

    Tdr100 6: tdr100 measurement (p119) 1: 00 sdm address 2: 0 la/l 3: 1108 mmmp mux & probe selection 4: 4 waveform averaging 5: 1 vp 6: 250 points 7: 9.5 cable length (meters) 8: 5 window length (meters) 9: .3 probe length (meters) 10: .085 probe offset (meters) 11: 17 loc [ wc_1101 ] 12: 1138 mult 13...

  • Page 55

    Tdr100 ;turn off the switched 12v to power off the tdr100: 9: do (p86) 1: 55 set port 5 low ;now, after making the measurements, set the output flag. ;remember this is only done once an hour 10: do (p86) 1: 10 set output flag high (flag 0) ;instruction 80 is used to set the output array id to 60: 11...

  • Page 56

    Tdr100 figure 10-1. Twenty-nine cs605 or cs610 probes connected to 4ea sdmx50 multiplexers. Example 5, trouble shooting program for sdmx50 multiplexer, datalogger control ports, and analog measurements the following program can be used to test the operation of the sdmx50 multiplexer and the datalogg...

  • Page 57: 11.  References

    Tdr100 ;note: while flag 1 is high instruction 109 will take control of the ;sdm ports 1-3. It may not be possible to follow the ports ;going high and low with a voltmeter while this is happening. 2: if flag/port (p91) 1: 11 do if flag 1 is high 2: 30 then do 3: sdmx50 channel select (p109) 1: 01 sd...

  • Page 58

    Tdr100 52.

  • Page 60

    Campbell scientific companies campbell scientific, inc. (csi) 815 west 1800 north logan, utah 84321 united states www.Campbellsci.Com • info@campbellsci.Com campbell scientific africa pty. Ltd. (csaf) po box 2450 somerset west 7129 south africa www.Csafrica.Co.Za • cleroux@csafrica.Co.Za campbell sc...