User guide

Charnwood Dynamics Ltd. Coda cx1 User Guide – Coda Basics I - 1
CX1 USER GUIDE - COMPLETE.doc 26/04/04 35/162
The choice between parallel/perpendicular alignment and an arbitrary orientation using
alignment transforms is made in the CODA Configuration dialog (CODA menu:
Configuration… command)
If the ‘Aligned’ configuration is selected, then alignment transforms must be available
before data acquisition is allowed.
Parallel or Perpendicular Alignment
Each Coda needs to be physically aligned with the room/walkway in the same way as a
single Coda, using a triangle of markers on the floor.
Both Codas may be aligned to the same triangle of markers if the markers are made
visible to both Codas by placing them flat on the floor. The Real-time marker display
shows separate co-ordinates for each Coda when a Parallel/Perpendicular configuration is
selected.
However, when markers are at a high angle to Coda, the signal received at Coda is
relatively weak and the measured co-ordinates may be inaccurate and noisy. It may be
better to align each Coda with the markers facing each Coda in turn, being careful not to
rotate the axes defined by the markers when they are moved (translation of the axes
doesn’t affect the alignment).
A common origin is set with a single marker when the Origin is defined at the beginning of
each measurement session.
Creating an Alignment Transform
When the Codas are positioned in an arbitrary orientation to the room and/or to each
other, alignment transforms must be created for each Coda in the same way as for a
single Coda.
It is possible to create alignment transforms for both Codas simultaneously if the markers
defining the co-ordinate axes are made visible to both Codas – the Alignment dialog has
check boxes for each Coda. However, this is likely to mean that the markers will be at a
high angle to one or both Codas, which could result in an inaccurate alignment, so it may
be better to align each Coda separately, with markers facing Coda. This also ensures that
the markers will be clearly in view of each Coda during the alignment procedure.
It is not necessary to have a common origin when creating the alignment transforms, as
long as there is no rotation of the marked axes for each Coda. The alignment transform
matrices are purely rotational; a common origin is set independently of the rotational
transform with the Define Marker Origin function (which must be executed at the
beginning of each measurement session).
To ensure that the axes to which each Coda is aligned are parallel, use pairs of markers
stuck together back-to-back, and orientate each pair in the same direction (parallel to the
X-axis). This of course means entering different marker numbers in the alignment dialog
for each Coda.