DMC-1500 Chapter 6 Programming Motion • 63
Contour Mode
The DMC-1500 also provides a contouring mode. This mode allows any arbitrary position curve to be
prescribed for 1 to 8 axes. This is ideal for following computer generated paths such as parabolic,
spherical or user-defined profiles. The path is not limited to straight line and arc segments and the
path length may be infinite.
Specifying Contour Segments
The Contour Mode is specified with the command, CM. For example, CMXZ specifies contouring on
the X and Z axes. Any axes that are not being used in the contouring mode may be operated in other
modes.
A contour is described by position increments which are described with the command, CD x,y,z,w
over a time interval, DT n. The parameter, n, specifies the time interval. The time interval is defined
as 2
n
ms, where n is a number between 1 and 8. The controller performs linear interpolation between
the specified increments, where one point is generated for each millisecond.
Consider, for example, the trajectory shown in Fig. 6.4. The position X may be described by the
points:
Point 1 X=0 at T=0ms
Point 2 X=48 at T=4ms
Point 3 X=288 at T=12ms
Point 4 X=336 at T=28ms
The same trajectory may be represented by the increments
Increment 1 DX=48 Time=4 DT=2
Increment 2 DX=240 Time=8 DT=3
Increment 3 DX=48 Time=16 DT=4
When the controller receives the command to generate a trajectory along these points, it interpolates
linearly between the points. The resulting interpolated points include the position 12 at 1 msec,
position 24 at 2 msec, etc.
The programmed commands to specify the above example are:
Instruction Interpretation
#A
CMX Specifies X axis for contour mode
DT 2 Specifies first time interval, 2
2
ms
CD 48;WC Specifies first position increment
DT 3 Specifies second time interval, 2
3
ms
CD 240;WC Specifies second position increment
DT 4 Specifies the third time interval, 2
4
ms
CD 48;WC Specifies the third position increment
DT0;CD0 Exits contour mode
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