Galil DMC-3425 user manual Command Summary - Contour Mode, Operand Summary - Contour Mode

Additional Commands

The command, WC, is used as a trippoint "When Complete" or “Wait for Contour Data”. This allows the DMC-3425 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

CM AB

CD a,b

DT n

WC

Description

Specifies which axes for contouring mode. Any non-contouring axes may be operated in other modes.

Specifies position increment over time interval. Range is +/-32,000. Zero ends contour mode.

Specifies time interval 2n 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.

Waits for previous time interval to be complete before next data record is processed.

Operand Summary - Contour Mode

Operand

_CS

Description

Return segment number

General Velocity Profiles

The Contour Mode is ideal for generating an arbitrary velocity profile. 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. 6.6. 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= (A/B) [1 - cos (2πΤ/B)]

X= (AT/B) - (A/2π)sin (2πΤ/B)

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 - (6000/2π) sin (2π T/120)

Note that the velocity, ω, in count/ms, is

DMC-3425 Chapter 6 Programming Motion• 91