Inclinometer Sensors / Tilt Sensors

Accuracy of inclinometers is dependent on the technology used within the sensor, tolerances of machined parts and the calibration methods used. The most common technology is MEMS (Micro-electromechanical system) which will offer accuracies between 0.3 degree for an industrial to 0.002 degree for a high accuracy sensor. It is important to remember that the smaller the inclination measured, the better the accuracy that will be derived.

Inclinometers can be made using several technologies and each has its own pros and cons. Most inclinometers are for static applications such as the three types below. 

• Fluid inclinometers use a small bowl-shaped container with a conductive fluid inside.  As the sensor is rotated, the fluid moves around the bowl due to gravity creating an output signal which varies accordingly. These devices are best for slow-moving applications. The fluid can be affected by external vibrations which may cause mis-reads caused by wave-like motion in the sensor. 
• MEMS inclinometers use a Micro Electro-Mechanical System which is etched onto a silicon chip.  The MEMS device operates similar to a pendulum with the fall of the pendulum always pointing downwards due to gravitational pull. As the mechanical structure is so small it allows for fast movements but can also be affected by external vibrations which may cause the inclinometer to behave like an accelerometer.
• Servo inclinometers also known a force-balance inclinometers operate with a mass mounted in an electromagnetic field. As the mass is subjected to motion, the sensor adjusts the electromagnetic flux to keep the mass in the centre of the field. The amount of correction required is converted to an output signal which is proportional to the inclination of the sensor. This method can be very accurate, but is also very slow in reaction. Often the mass is damped in oil to prevent over-compensation. 

For dynamic applications, or where vibration or accelerations are present the technology used changes.  In these cases a combination of accelerometers and gyroscopes are used to calculate the angular change of the sensor these often also use MEMS technology. Many of these devices have a digital output and have an internal processor to calculate the inclination angle relative to gravity. Some of these sensors can also be used as an IMU (inertial measurement unit) depending on the output options of the signal.
 

There are several different technologies used for inclinometers but essentially they all have the same purpose.  They measure the inclination, or angle of an object with respect to the force of gravity. This value is given as an output in an analogue or digital signal from the sensor which varies proportionally to the angle and range of the sensor. 

Care must be taken to understand digital inclinometer as it can either mean an inclinometer with a digital output or have a digital screen which shows the output. By far the most common is an inclinometer with a digital screen, used for levelling in construction. Digital output inclinometers are usually high performance and high accuracy sensors.  

There is no real difference between an inclinometer and a clinometer however, clinometers can be used to measure slope and is a more manual device. They have several names including tilt sensor, tilt meter, slope gauge, pitch & roll indicator.

An inclinometer or clinometer is used for measuring slopes or angles of elevation. Some inclinometers have specific ranges and will only be able to measure small angles, whereas others can measure any angle up to a full 360 degrees of rotation. Wider range inclinometers tend to have lesser accuracy so your choice of sensor may not only depend on the range, but also the tolerance or accuracy required of the measurement. So yes an inclinometer can be used as a level within the specified range of the model chosen.

The majority of inclinometers require a reference point to calculate the angle of inclination of a surface or slope.  We use the gravitational pull of the earth as the reference and so gravity is required for most inclinometers to operate. Therefore most inclinometers are not suitable for use where there is no, or insignificant gravitational pull.