Movements of the sensor and the effect on the measured value

The sensor has two axis: X-axis and Y-axis. The X-axis is defined as the long side of the sensor. The Y-axis is defined as the short side of the sensor. When a sensor is mounted to an object (e.g. a concrete wall) the X- and Y-axis are leveled to zero (0) with the leveling screws* . 

In the Tilting-plots the inclination over time is shown. To understand deformation of the measured object, the picture below helps us interpret what happened.

The StabiAlert Coordinate system

X-axis

When the plot of the X-axis inclines over time, the sensor is tilting in such a way that the cable sockets are going up. (In this projection the the sensor rotates clock-wise around the Y-axis)

Y-axis

When the plot of the Y-axis inclines over time, the sensor is tilting in such a way that the left cable socket is higher then the right cable socket.  (In this projection the the sensor rotates clock-wise around the X-axis)

Inverse mode

When the sensor is in inverse mode, the sensor-values are multiplied by -1. The Inverse mode can be set for X-axis or The Y-axis or both. (the clock-wise rotation for either X- or Y-axis results in declining plot. )

Swap mode

When the sensor is in swap-mode the physical X- and Y-axis are swapped. (X-axis becomes Y-axis and Y-axis becomes X-axis

Application for Inverse- and Swap-mode

In practice not all sensors can be mounted to a construction in the same directions. In this case the engineer chooses one sensor as reference sensor for the direction.Usually he/she chooses the direction in such a way that most sensors are in the same physical direction. Sensors that can not be mounted in de the correct physical direction are configured with the Inverse- or Swap-mode to make them appear to be in de same direction as the reference direction.

 

*) Leveling the sensors to the real zero (0) value is physically impossible due to the sensors extreme sensitivity. In practice when maintain a 0.001° margin approximately. After the sensor stabilizes we calibrate  the current off-set to the zero-offset.

Swap & Invert definitions

To match the orientation between the coordinate system of most 3D CAD software, StabiFrame and the object to monitor, the image below defines the configuration settings of the sensors according to their position inside the object.

Sensor Swap and Axis invert definitions (Click to enlarge)