Extended Alignment Routine
The normal method of alignment described above is not viable if it is impossible for all CODA units to see one common point or region where the axis markers can be placed. The ‘extended alignment option’ is provided to overcome this difficulty. The ‘extended alignment option’ allows the user to specify which CODA units are to be used in an alignment and how the origin of the axes system used for that particular alignment is displaced from the actual origin (i.e. the offset). The extended alignment option is chosen by selecting: Hardware > Extended CODA alignment
The layout of the extended alignment menu is very similar to that used in normal alignment, except for the ‘Extended Alignment’ box at the bottom as shown.
Markers for the local origin, X-axis 1, X-axis 2, XY-plane 1 and XY-plane 2 are set up as described in Performing an Alignment. The CODAs to be used for that particular alignment are then selected using the tick boxes in the ‘Extended Alignment’ box, and the offset of the local origin to the universal origin (in terms of x, y, and z distances in millimetres on the universal frame) are entered. Alignment is initiated by pressing the ‘Align’ button.
Extended Alignment Example
Suppose CODA 1 and CODA 2 can see the true (universal origin), but this is outside the view of CODA 3 and CODA 4. However, suppose that CODA 3 and CODA 4 can see a point 2 metres along the X axis. This point can be used as a ‘local origin’ for CODA 3 and CODA 4. Two extended alignments would be used:
- Aligning to the true (universal) axes:
- Using markers placed around the universal (true) origin with zero offset, CODA 1 and CODA 2 would be selected in the ‘Extended Alignment’ box. An offset of x=0, y=0, z=0 would be entered
- Press on “Align” to align CODA 1 and Coda 2
- Aligning to the local (offset) axes:
- Using markers placed around a point 2 metres along the X axis, CODA 3 and CODA 4 would be selected in the ‘Extended Alignment’ box. An offset of x=2000, y=0, z=0 would be entered.
- Press on “Align” to align CODA 3 and Coda 4
NOTE 1: Success or failure of the alignment attempt is notified by the set of messages described in the “Unsuccessful Alignment and Diagnostic” section.
NOTE 2: When using this method, it is important that the X, Y and Z axes of any local axes set used are parallel and in the same direction with the corresponding axis of the universal frame (i.e. the two X axes are parallel and in the same direction to each other, the two Y axes are parallel and in the same direction to each other and the two Z axes are parallel and in the same direction to each other.
Note 3: The ‘extended alignment option’ may also be used to create an actual origin in a position where a physical marker cannot be placed. This may be useful, for example, if the user wants to set the exact surface of the floor or a force plate as the zero point. Only a single extended alignment is required, but with ‘offset’ values to define the desired origin.