VC4000 Manual
77
Figure 28: VC4000 Axis Summary
Summation of the
acceleration vectors
means taking 2 or 3
acceleration values from different angles and calculating the vector
sum. Once the vector sum is calculated it is shown as “G” instead of
Gx, Gy and Gz if 3D summation is on.
2D summation:
2
2
Gy
Gx
G
Figure 29: Vectors
2D summation uses the X and Y axes to calculate a vector sum.
This vector sum is then the new acceleration, “G”. The Z axis is still
monitored and stored. Use 2D summation if mounting the VC4000
flat and level but the X axis is not necessarily in line with the test
direction, such as on an angled windshield like on a split window
bus, or on a curved windshield where the VC4000 is mounted to one
side. The VC4000 must be mounted with the front to back and side
to side level with the road surface when using 2D summation. Use
the bubble levels if the surface is level.
