Campbell Scientific TDR100 Time Domain Reflectometry Systems - Manual (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 setup. Saves as
.mux file.
Print Graph - send displayed graph to default printer
Exit - quit PCTDR
4.3.2 Settings Menu
Communication - select communication serial port and baud rate
Waveform Selection - select reflection waveform or reflection waveform plus
first derivative
Multiplexer - configure multiplexer switching
Calibration Function - select calibration functions for volumetric water content
and bulk electrical conductivity
Units - select meters or feet
4.3.3 Options Menu
Terminal Emulator - line command mode of PCTDR
Advanced - link for downloading TDR100 operating system
4.4 PCTDR Parameter Selection Boxes
4.4.1 Cable
The cable propagation velocity, Vp, depends on the dielectric constant of the
insulating material between the coaxial cable center conductor and outer
shield. The value entered in this parameter selection box is the ratio of the
actual propagation velocity for a selected medium to the propagation velocity
in a vacuum (3 x 10
8
m sec
-1
). Specific V
p
values for each coaxial cable are
available from manufacturer data books. It is only necessary to know the V
p
value if the TDR100 is used as a cable tester for finding cable lengths or faults.
See Section 3.1 for a discussion of propagation velocity.
Calculation of water content or electrical conductivity is independent of the
chosen value for V
p
because V
p
cancels in the calculation. However the V
p
value does affect waveform display.
For water content measurements, it is recommended that propagation velocity,
Vp, be set at 1.0.
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