Geokon 1900, Инструкция по эксплуатации

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Anchor points with permanent magnets are anchored in the ground with a continuous access tube
passing through their center. A reed switch probe is lowered inside the access tube on the end of
a graduated measurement tape, which also contains two electrical conductors. As the probe
passes each anchor, the magnets in the anchor cause the reed switch to close, this sounds a
buzzer on the tape reel at the surface.
When the buzzer sounds the depth of the anchor is measured by reading the graduated tape
opposite the top of the access tube.
In most cases, the bottom of the access tube is deep enough to be located in solid ground. A
datum magnet anchored to the bottom of the access tube provides a stable benchmark datum to
which all the other anchor measurements are referred to in order to calculate the absolute
settlement of each anchor point relative to the benchmark.
If the bottom of the access tube cannot be located in the solid ground then it will be necessary to
reference the position of each anchor to the top of the access tube and to transfer this elevation to
an external benchmark by normal level surveying techniques.