Geotechnical (electrolytic) inclinometers

Yes. Many geotechnical inclinometers are designed for stable measurements over a defined temperature range and, depending on the model, feature an integrated temperature sensor, temperature compensation or optional temperature calibration.

Digital models such as the D711 Floor-Mount Tiltmeter offer programmable functions including sample averaging, auto-zero, adjustable output rate and temperature compensation. In addition to X- and Y-axis inclination, they also provide a temperature channel. The typical temperature range is -25 °C to +70 °C.

Analogue geotechnical inclinometers such as the A603 Platform Tiltmeter also feature an additional temperature channel and are designed for stable long-term measurements in the field. Depending on the model and measurement task, it should be determined whether factory calibration, application-specific temperature compensation or calibration of the complete measurement system is required.

For particularly demanding field and monitoring applications, the temperature range, required accuracy, long-term stability and data acquisition should be considered together. This helps ensure that the selected geotechnical inclinometer provides reliable measurement values even under changing ambient temperatures.

The resolution of geotechnical inclinometers depends on the sensor type, measuring range and output signal. For high-precision geotechnical and structural monitoring applications, models are available with very fine resolution in the nano- or microradian range.

For example, the 500 Self-Leveling Borehole Tiltmeter, known as Lily, achieves a resolution of 5 nanoradians. The A603 High Precision Platform-Mount Tiltmeter offers a resolution of < 2.5 nanoradians, depending on the version. Digital models such as the D711 Floor Mount Tiltmeter achieve resolutions of 1 µrad, 10 µrad or 4 arc seconds, depending on the measuring range.

The required resolution depends on whether the application involves monitoring very small ground movements, structural deformation, platform inclination or larger displacements. Althen can help select a geotechnical inclinometer with the appropriate resolution, accuracy and long-term stability.

The data rate of geotechnical inclinometers depends on the model, interface, sensor type and application. Depending on the model, digital versions can operate with configurable communication parameters, for example via RS485 or RS422. This allows them to be integrated flexibly into data loggers, monitoring systems or industrial data acquisition systems.

For analogue geotechnical inclinometers, no fixed digital data rate is specified. In this case, the connected measurement system or data logger determines how quickly the measurement values are acquired and processed.

For long-term geotechnical monitoring, lower sampling rates are often sufficient, for example when monitoring ground movement, structural inclination or settlement. More dynamic applications may require a higher data rate. Althen can help select a geotechnical inclinometer with a suitable data rate and data acquisition system for the application.

The power supply for geotechnical inclinometers depends on the sensor model and the data acquisition system used. In the field, many geotechnical inclinometers are powered via a connected measurement system, data logger, monitoring unit or battery. These systems provide the required supply voltage while acquiring the measurement signals.

Analogue models such as the A603 or the weatherproof 711-2 Platform Tiltmeter operate with a symmetrical supply of ±11 to ±15 VDC. Digital models such as the D711 are integrated via their respective digital interface into data logger, RS485/RS422 or monitoring systems.

For long-term field measurements, for example in structural monitoring, geotechnical applications or slope monitoring, power can be supplied via stationary power supplies, control cabinet solutions, data loggers or autonomous systems. The appropriate solution depends on the sensor type, cable length, output signal, measurement interval and site conditions. Althen can help select a suitable power supply and data acquisition solution for field use.

The time constant and achievable measurement rate of geotechnical inclinometers depend strongly on the specific inclinometer, interface and selected filtering. In geotechnical applications, the priority is often not maximum measurement speed, but stable, low-noise and reliable long-term inclination measurement.

Digital models such as the D711 have a specified time constant of 0.15 s. Parameters such as sample averaging, auto-zero, baud rate and output rate can also be configured via the firmware. The D711 can additionally store up to 22,000 measurement values internally.

For analogue geotechnical inclinometers, the connected measurement system or data logger usually determines how many measurement values are recorded per second. Low-pass filters or the damping characteristics of the sensor can also smooth the signal and reduce the influence of rapid disturbances.

In practice, the measurement rate should always be matched to the application. For long-term monitoring of structures, bridges, slopes or foundations, low sampling rates are often sufficient. For more dynamic applications, such as vibration or rapid changes in position, the time constant, bandwidth, filtering and data acquisition need to be specified more carefully. Althen can help select a suitable sensor and measurement rate for the monitoring task.