Osprey Measurement Systems ospreymeasurement.systems
Before you start
The Installation
Reed switch probe 2mm hex driver Permanent marker pen
Cable ties
Conrm your magnetic extensometer access tube is free of damage or debris and is not excessively deformed.
Note: Your magnetic extensometer access tube should be installed as straight as possible to ensure best measurement
performance and ease of installation of the IPX.
To avoid damaging the IPX cable during installation, we recommend deburring the ends of the access tube, which can develop
sharp edges and burrs during the manufacturing process.
1. Mark the magnet depths on the GRP rod
2. Using the gauge on the back of the IPX, align the sensor with the corresponding depth marking.
Note: You should position the IPX such that the majority of sensing range is in the direction of expected movement.
See section 3.3.3 of the user guide for further information.
3. Tighten the grub screws using the 2mm hex driver until the support rod appears white – approx. 0.5Nm.
Tighten both screws on one end rst and then the other, ensuring the rod is taught between the two ends.
4. Ensure the cable is safely xed to the rod between sensors. This should be done using cable ties. Excess cable is folded
into itself and secured in at least two positions using cable ties as shown. Trim the cable ties using sharp snips.
5. Insert the end of the GRP rod into the bottom support and tighten the grub screws.
6. Carefully lower the string into the access tube. The IPX is guided into the tube being careful to avoid snagging of the
cable or sensors on entry. Make the angle as large as possible so the IPXs entervertically with minimum stress on the
GRP rod at the grub screw locations.
7. Once the string has reached its nal position, place the top support in the access tube.
Note: the top support should not be carrying any weight in a bottom supported installation. In a top suspended installation,
the IPX string should be raised off the bottom of the access tube sufciently that the string shall not come into contact with
it for the duration of the monitoring period. For more details, see section 3.3.2 of the user guide.
Connect the string to a data logger, laptop orsmartphone to conrm the measurements given by the instruments match
the intended position of the sensors relative to the magnets. See data logger specific guides for reference.
Conduct a manual survey of the borehole using a reed switch probe.
Note: Many magnets will exhibit hysteresis, activating the reed switch probe over a distance of up to 25mm. To locate the centre
of the magnetic peak, note the depth at which the reed switch is activated, and then again when it is deactivated. Halfway
between these positions is the centre of the magnetic peak.
Take a note of the serial numbers of all IPX sensors, and their position in the string.
Snips Top and bottom support
In-Place Extensometer (IPX)
Quick Guide – Installation
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