Multitasking - ABB IRB 6400R Product On-Line Manual

3.3 Multitasking

Up to 10 programs (tasks) can be executed in parallel with the normal robot program.
- These additional tasks start automatically at power on and will continue until
the robot is powered off, i.e. even when the main process has been stopped and
in manual mode.
- They are programmed using standard RAPID instructions, except for motion
instructions.
- They can be programmed to carry out various activities in manual or automatic
mode, and depending on whether or not the main process is running.
- Communication between tasks is carried out via I/O or global data.
- Priorities can be set between the processes.
Examples of applications:
- The robot is continuously monitoring certain signals even when the robot pro-
gram has stopped, thus taking over the job traditionally allocated to a PLC.
- An operator dialogue is required at the same time as the robot is doing, for
example, welding. By putting this operator dialogue into a background task, the
operator can specify input data for the next work cycle without having to stop
the robot.
- The robot is controlling a piece of external equipment in parallel with the nor-
mal program execution.
Performance
When the various processes are programmed in the correct way, no performance
problems will normally occur:
- When the priorities for the various processes are correctly set, the normal pro-
gram execution of the robot will not be affected.
- Because monitoring is implemented via interrupts (instead of checking condi-
tions at regular intervals), processor time is required only when something
actually happens.
- All input and output signals are accessible for each process.
Note that the response time of Multitasking does not match that of a PLC. Multitasking
is primary intended for less demanding tasks.
The available program memory can be divided up arbitrarily between the processes.
However, each process in addition to the main process will reduce the total memory,
see section 5.1.
Product Specification RobotWare for BaseWare OS 3.2
Multitasking 3.2
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