Campbell Scientific TDR100 Time Domain Reflectometry Systems - Manual (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
GROUND
CS I/O
0
Logan, Utah
TDR100
TIME DOMAIN REFLECTOMETER SDM
S/N
MADE IN USA
RS232 +12V GR
OUND
C1 D
A T A
C2 CLOCK C3 ENABLE
SELECTION SDM ADDRESS 0 00 1 01 2 02 3 03 4 10 5 11 6 12 7 13 8 20 9 21 A 22 B 23 C 30 D 31 E 32
Logan, Utah
MADE IN USA
SDMX50
50 OHM MULTIPLEXER
GROUND +12V DATA CLOCK ENABLE C1 C2 C3
PS12 POWER SUPPLY
WITH 12V CHARGING REGULATOR
MADE IN USA
WARNING:
PERMANENT DAMAGE TO RECHARGEABLE
CELLS MAY RESULT IF DISCHARGED
BELOW 10.5 VOLTS
FUNCTION
INT
EXT BAT
CHG
OFF ON
CHG CHG
+12
+12
PS12 BATTERY
EXTERNAL BATTERY - DO NOT USE WITH
INTERNAL RECHARGEABLE BATTERY CHARGE VOLTAGE PRESENT
INPUT FROM CHARGER OR SOLAR PANEL
16-26 VDC OR AC RMS: POSITIVE TO
EITHER TERMINAL, NEGATIVE TO OTHER
POWER TO DATALOGGER OR
12V PERIPHERALS
(Not intended to be used as
wiring guide.)
ENCTDR100 shown with
PS12 power supply, CR10X
datalogger, TDR100, and
SDMX50SP coaxial
multiplexer.
5.8 Soil Probes
The TDR probes are the sensors of the TDR measurement system and are
inserted into the medium to be measured. The probes are a wave guide
extension on the end of coaxial cable. Reflections of the applied signal along
the waveguide will occur where there are impedance changes. The impedance
value is related to the geometrical configuration of the probe (size and spacing
of rods) and also is inversely related to the dielectric constant of the
surrounding material. A change in volumetric water content of the medium
surrounding the probe causes a change in the dielectric constant. This is seen
as a change in probe impedance which affects the shape of the reflection. The
shape of the reflection contains information used to determine water content.
Both volumetric water content and electrical conductivity can be measured
using fixed spacing 2-rod designs and 3-rod designs (CS605 and CS610).
17