3M 965DSP - K-Test

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K-Test
Use this function to find the approximate distance
to a resistance fault when both wires in a single pair
are faulted at the same place, and a separate good
pair or a single loop conductor is not available.
Resistance Check
Before you start the K-Test measurement, use the
Resistance function to measure the resistance from
both sides of the pair to the reference conductor.
The resistance faults must be common to the
reference conductor.
One fault must be at least twice as “heavy” as the
other fault (e.g., 5k
Ω is twice as “heavy” as 10kΩ).
The sum of both faults must be at least 100 times the
loop resistance of the pair (for instance, if the loop
resistance is 50
Ω , the fault sums must be 5k Ω or
greater).
The K-Test first makes a measurement with the far-
end “open” (the strap disconnected).
And then repeats the measurement with the far-end
“closed” (the strap connected).
You may choose to use a “far-end switch” to open
and close the far-end. The 3M KM Box Model 1162
is recommended for this application. The 965DSP
will automatically send tones on the blue and yellow
leads to communicate with the 3M KM Box (far-end
switch).
The far-end can be manually opened and shorted
during the test. However, be aware of timeout issues
that may occur.
K-Test Setup
The K-Test Setup screen is identical to the RFL
Setup screen. Press the [Setup] key to change the
gauge or temperature.