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Spiral Sensor


spiral sensor
Datasheet Manual

Inclinometer casing controls the orientation of the inclinometer probe. If the casing is twisted, the orientation of the probe will vary, and the resulting data will indicate an incorrect magnitude of movement in the A and B directions. The spiral sensor checks for spiral and provides measurements that can be used to correct inclinometer data obtained from spiraled casing.

Although not required for most inclinometer installations, spiral surveys are recommended when:

  • The installation is very deep.
  • Inclinometer readings indicate movement in an unlikely direction.
  • Extreme accuracy is required.
  • Difficulties were experienced during installation of the casing.


The spiral sensor, connected to an inclinometer control cable and read-out, is lowered to the bottom of the casing. Spiral readings are recorded at 1.5-meter (or 5-foot) intervals as the sensor is drawn to the top of the casing. Readings are displayed in arc minutes. In a full spiral survey, the sensor is drawn through the casing four times, with its orientation changed 90 degrees each time.

Data Reduction

If spiral correction is required, the data is processed with specialized software such as Slope Indicator's DigiPro2 program. DigiPro2 calculates the spiral correction required at each inclinometer reading depth, and then automatically applies the correction when it generates a plot.


Checks Installation: The spiral sensor can be used to verify that casing was installed properly, without spiral.

Improves Accuracy: Spiral correction can improve accuracy and ease interpretation of data. In some cases, spiral correction allows continued use of inclinometer casing that would otherwise be abandoned or replaced.

Works with Digitilt Hardware: The spiral sensor is compatible with inclinometer control cable and Digitilt indicators. No additional equipment is required.

Supported by DigiPro2 Software: DigiPro2 software can plot spiral directly for evaluation and if necessary, generate correction values for each depth, and apply the corrections when the inclinometer data is plotted.


For more information

Please download the data sheet and manual for the Spiral Sensor . These documents can be viewed and printed with Adobe Acrobat Reader.