Fault Mapper Pro
®
Model CA7027
11
NOTE:
The auto-off function is disabled in Tone Generator mode, so that
the tone can be injected into a cable for an extended period of time while
tracing takes place.
See §4.10 for attaching a cable to the Fault Mapper Pro
®
4.7
Selecting Full Scale Sensitivity
The Fault Mapper Pro
®
has 11 range scales covering the range of 1.5 to
19,000 ft (0.5 to 6000m).
To select a range scale, or scan the cable run, press and hold down the
TDR /
button, then press the button to decrease the range or the
button to increase the range.
4.8
Adjusting the Vp Value
To adjust the Vp, press and hold the
TDR /
button and press the
TEST /
button to enter the setup mode. Release both buttons. Press the
TEST /
button until the pointer (
>
) is next to Vp.
Next use the
and
buttons to adjust the Vp to scroll between v/2, M/Ms
or Vp % UC.
Press the
TDR /
button to exit the set up mode.
4.9
Determining and Measuring Vp Values
Vp, or Velocity of Propagation, values are characteristic of each cable
type and brand. The Vp is used to measure the length of a cable and to
measure a fault location. The more accurate the Vp, the more accurate the
measurement result will be.
The cable manufacturer may list the Vp on their specification sheet or may
be able to provide it when asked. Sometimes this value is not readily avail
-
able, or the user may wish to determine it specifically to compensate for
cable batch variations or for special cable applications.
1. Take a cable sample of exact length increments (ft or m) longer than
300 ft (100m).
2. Measure the exact length of the cable using a tape measure.
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.com
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