Galil Motion Control DMC-1600 Series, User Manual

Page: 105 / 214

Additional Commands
The command, WC, is used as a trippoint "When Complete". This allows the DMC-1600 to use
the next increment only when it is finished with the previous one. 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-1680
CD x,y,z,w Specifies position increment over time interval. Range is +/-32,000. Zero ends contour
mode.
CD
a,b,c,d,e,f,g,h Position increment data for DMC-1680
DT n Specifies time interval 2
n
msec 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.
WC Waits for previous time interval to be complete before next data record is processed.
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. 6.7. 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:
(
ω
= −
Α
Β
Β
1 2 cos( )
)
π
Χ = −
AT
B
A
B
2
2
π
π
sin( )
Note:
ω
is the angular velocity; X is the position; and T is the variable, time, in milliseconds.
In the given example, A=6000 and B=120, the position and velocity profiles are:
X = 50T - (6000/2
π
) sin (2
π
T/120)
Note that the velocity,
ω
, in count/ms, is
ω
= 50 [1 - cos 2
π
T/120]
DMC-1600 Chapter 6 Programming Motion
•
97