Digital Inclinometer System: Introduction & How does it Work

A digital inclinometer makes use of an Android OS mobile phone having a Bluetooth wireless interface as a readout device. The latest Android devices have a large 800 x 480-pixel colour display with a responsive touch screen that makes it easy to readigital inclinometer systemd while logging boreholes.

Encardio-rite’s Model EAN-26 readout unit logs profiles of boreholes up to 300 meters deep in 0.5/1.0 meters increment or up to 999 feet deep in 2.0/4.0 feet increment, using either biaxial or uniaxial inclinometers.

The readout unit can store readings from more than 1000 boreholes. The data remains even if the power is turned off. The logged data can also be uploaded to a remote FTP server using GPRS/3G cellular network. It can also be easily imported to third party inclinometer data presentation software like GTilt or a spreadsheet program like Microsoft Excel.

Since the readout unit is a mobile phone, most of the people are familiar with its operation. Continue reading to know what is a digital inclinometer and how is it used.

What is a Digital Inclinometer

The Encardio-rite Model EAN-26, a digital inclinometer system is used for measuring lateral movement in applications like:

• Earth movement in the landslide zone.
• Detecting shear planes in hydraulic structures.
• Measuring stability during construction.
• Deflection of diaphragm/retaining walls and piles under load.

The Model EAN-26 digital inclinometer system basically consists of:

• Access casing and fittings
• Tilt sensing probe
• Interconnecting cable with reel and cable holder
• Mobile phone data logger

The digital inclinometer system provides significant quantitative data on the magnitude of inclination and its variation with time. It gives complete information on the pattern of deformation and effectiveness of construction control measures.

The inclinometer system helps in monitoring behaviour after construction and indicates potentially dangerous conditions that may adversely affect the stability of the structure, its foundation and surrounding area.

It also provides essential data for design improvement to promote safer and economical design and construction. The EAN-26 digital inclinometer system is an accurate instrumentation system. Its readout (Android-based mobile device) has built-in data storage facilities and capability of transferring stored data to a computer.

The inclinometer probe operates in a plastic grooved casing which may be “built-up” with embankment fill, inserted into boreholes or attached externally to structures or hillsides. The inclinometer casing may be installed with telescopic couplings as construction progresses providing an opportunity for settlement measurements. It may be installed with butt joints in drill holes, abutments or completed embankments if no significant settlement is anticipated.

How does Digital Inclinometer Work?

Inclination Measurement

The inclinometer probes use an accelerometer to measure the tilt angle from the true vertical line or horizontal plane with respect to the earth’s surface. The accelerometer itself measures the change in acceleration due to gravity felt by it as it rotates about a horizontal axis.

The accelerometer experiences maximum acceleration when its sensitive axis is truly vertical and minimum acceleration when its sensitive axis is truly horizontal.

In a vertical inclinometer probe, the internal accelerometer is mounted such that when the inclinometer probe is truly vertical, the accelerometer sensitive axis is aligned vertically.

In a horizontal inclinometer probe, the accelerometer sensitive axis is aligned vertically when the probe is aligned along a true horizontal plane. As the accelerometer rotates about a horizontal axis along a vertical plane, its output changes proportionally to the sine of the angle its sensitive axis makes from the true vertical.

So an inclinometer’s output is generally proportional to the sine of the angle of tilt (or inclination) rather than the tilt angle of the inclinometer probe itself. However, this sine law variation of an inclinometer probe output is more useful to us as the subsequent calculations to determine the ground profile uses the sine of the tilt angle rather than the tilt angle itself.

A uniaxial vertical inclinometer probe can measure the tilt along a vertical plane passing through the probe axis. A biaxial inclinometer probe can measure the tilt independently along two vertical planes that are orthogonal to each other, with their intersection line coincident with the inclinometer probe axis.

A horizontal inclinometer probe is generally used to measure tilt along a vertical plane passing along the axis of the inclinometer. A second accelerometer is often provided to measure the [Continue Reading…]