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In-Place Extensometer

Simple and smart automation of magnetic extensometers. Easy to install, adjust and retrieve, the IPX offers complete flexibility in settlement monitoring. 

How it works

The IPX is installed within standard magnetic extensometer installations, including standard 25mm access tube and 70mm inclinometer casing.

Sensors are positioned inside the access tube to align with the installed spider or plate magnets, held in position by a fiber reinforced rod. The sensor characterises the magnetic field created by the spider magnets and reports its position along the probe in millimetres. 

Coiled cable provides flexibility in positioning the sensors when on site. The sensors are easily relocated along the FRP rod using grub screws to secure the sensor in place. 

The sensors communicate over an RS-485 serial bus allowing easy data retrieval by most geotechnical data logging devices.  

The output tells you the position of the peak of the magnetic field in millimetres, so no data conversion is necessary. 


IPX Schematic



(l) 740mm x (Ø) 20mm


Marine Grade Stainless Steel 316L

Operating Temperature

-10°C to 65°C 

Power Requirements

4-16VDC, av. 25mA @ 12V


400mm (±200mm)






RS-485/ Modbus RTU



Low Power

Osprey Measurement Systems’ advanced protocol allows us to carry out sophisticated measurements and data processing without compromising battery life. Our low power design offers compatibility with battery operated data loggers without the need for an external power supply.


Easily Modify Sensor Positions

Our patented mounting system and coiled cable allows the installer to easily adjust the position of the IPX up or down the rod, without impacting the position of those above or below it. This can be useful where the stratum or a magnet is not at the expected depth.


User Defined Digital Commands

The digital output means only one signal cable is required to read an entire string of In-Place Extensometers.  We offer a selection of RS-485 command lists, giving you the flexibility to link your system to a wide variety of data acquisition and telemetry devices. 


Move With Your Project

Inevitably, extensometers are needed where ground level is either raised or lowered and the In-Place Extensometer is designed for adaptation. Thanks to our unique mounting and support design, extending or shortening an installation is made easy without compromising the other sensors.