Basic Characteristics RAPID

Positioning during Program Execution Motion and I/O Principles
programmed between short movements.
- The points are very close together at high speeds.
If stop points are a problem then use concurrent program execution.
2.4 Independent axes
An independent axis is an axis moving independently of other axes in the robot system.
It is possible to change an axis to independent mode and later back to normal mode
again.
A special set of instructions handles the independent axes. Four different move
instructions specify the movement of the axis. For instance, the IndCMove instruction
starts the axis for continuous movement. The axis then keeps moving at a constant
speed (regardless of what the robot does) until a new independent-instruction is
executed.
To change back to normal mode a reset instruction, IndReset, is used. The reset
instruction can also set a new reference for the measurement system - a type of new
synchronization of the axis. Once the axis is changed back to normal mode it is possible
to run it as a normal axis.
2.4.1 Program execution
An axis is immediately change to independent mode when an Ind_Move instruction is
executed. This takes place even if the axis is being moved at the time, such as when a
previous point has been programmed as a fly-by point, or when simultaneous program
execution is used.
If a new Ind_Move instruction is executed before the last one is finished, the new
instruction immediately overrides the old one.
If a program execution is stopped when an independent axis is moving, that axis will
stop. When the program is restarted the independent axis starts automatically. No
active coordination between independent and other axes in normal mode takes place.
If a loss of voltage occurs when an axis is in independent mode, the program cannot be
restarted. An error message is then displayed, and the program must be started from the
beginning.
Note that a mechanical unit may not be deactivated when one of its axes is in
independent mode.
2.4.2 Stepwise execution
During stepwise execution, an independent axis is executed only when another
instruction is being executed. The movement of the axis will also be stepwise in line
with the execution of other instruments, see Figure 24.
6-22 RAPID Reference Manual