Motion Control Instructions MOVE pick the robot begins moving toward the location by accelerating smoothly to the commanded speed. Sometime later, when the robot is close to the destination location pick, the robot decelerates smoothly to a stop at location pick. This motion is referred to as a single motion segment, since it is produced by a single motion instruction. When a sequence of motion instructions is executed, such as: MOVE loc.1 MOVE loc.2 the robot begins moving toward loc.1 by accelerating smoothly to the commanded speed 1 just as before. However, the robot does not decelerate to a stop when it gets close to loc.1.
Instead, it smoothly changes its direction and begins moving toward loc.2. Finally, when the robot is close to loc.2, it decelerates smoothly to a stop at loc.2. This motion consists of two motion segments since it is generated by two motion instructions. Making smooth transitions between motion segments without stopping the robot motion is called continuous-path operation. That is the normal method eV+ uses to perform robot motions. If desired, continuous-path operation can be disabled with the CP switch. When the CP switch is disabled, the robot decelerates and stops at the end of each motion segment before beginning to move to the next location. NOTE:
Disabling continuous-path operation does not affect forward processing (the parallel operation of robot motion and program execution). Continuous-path transitions can occur between any combination of straight-line and joint- interpolated motions. For example, a continuous motion could consist of a straight-line motion (for example, DEPARTS) followed by a joint-interpolated motion (for example, APPRO) and a final straight-line motion (for example, MOVES). Any number of motion segments can be combined this way.
Breaking Continuous-Path Operation Certain eV+ program instructions cause program execution to be suspended until the current robot motion reaches its destination location and comes to a stop. This is called breaking continuous path. Such instructions are useful when the robot must be stopped while some operation is performed (for example, closing the hand). Consider the instruction sequence: MOVE loc.1 BREAK SIGNAL 1 The MOVE instruction starts the robot moving to loc.1. Program execution then continues and the BREAK instruction is processed. BREAK causes the eV+ program to wait until the motion to loc.1 completes. The external signal is not turned on until the robot stops.
(Recall that without the BREAK instruction the signal would be turned on immediately after the motion to loc.1 starts .) eV+Language User's Guide, v2.x, 18318-000 Rev A Page 118