Galil DMC-4040, User Manual

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Figure 6.18: The Required Trajectory
Additional Commands
_CM gives the amount of space available in the contour buffer (511 maximum). Zero parameters for DT followed
by zero parameters for CD exit the contour mode.
If no new data record is found and the controller is still in the contour mode, the controller waits for new data. No
new motion commands are generated while waiting. If bad data is received, the controller responds with a ?.
Command Summary - Contour Mode
COMMAND DESCRIPTION
CM XYZW Specifies which axes for contouring mode. Any non-contouring axes may be operated in
other modes.
CM ABCDEFGH Contour axes for DMC-4080
CD x,y,z,w
Specifies position increment over time interval. Range is +/-32,000. CD 0,0,0.. .=0 ends the
contour buffer. This is much like the LE or VE commands.
CD a,b,c,d,e,f,g,h Position increment data for DMC-4080
DT n
Specifies time interval 2
n
sample periods (1 ms for TM1000) for position increment, where n
is an integer between 1 and 8. Zero ends contour mode. If n does not change, it does not
need to be specified with each CD.
_CM Amount of space left in contour buffer (511 maximum)
General Velocity Profiles
The Contour Mode is ideal for generating any arbitrary velocity profiles. The velocity profile can be specified as a
mathematical function or as a collection of points.
The design includes two parts: Generating an array with data points and running the program.
Generating an Array - An Example
Consider the velocity and position profiles shown in Fig. 6.14. The objective is to rotate a motor a distance of 6000
counts in 120 ms. The velocity profile is sinusoidal to reduce the jerk and the system vibration. If we describe the
position displacement in terms of A counts in B milliseconds, we can describe the motion in the following manner:
Chapter 6 Programming Motion
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111 DMC-40x0 User Manual
POSITION
(COUNTS)
240
96
48
192
TIME (ms)
0
4 8
12
16
20 24
28
288
336
SEGMENT 1 SEGMENT 2 SEGMENT 3