Delta ASD-A3-0121, User Manual

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ASDA-A3 Motion Control
Revision December, 2017
7-47
7
 PR queue
The triggered PR path is the lead PR. The PR group it leads goes into the PR queue to wait for
prioritization. In each ms, the servo drive sends the lead PR and the PR group it leads to the PR
executor no matter whether a PR path is being executed. Therefore, as long as a PR path is
triggered, the PR queue collects it and sends it to the executor.
 PR executor
Once the PR executor receives the lead PR and its PR group, the PR group in execution is
replaced immediately. If a PR group includes motion commands, such as Speed commands and
Position commands, then the PR executor sends them to the motion command generator. PR
paths with Write or Jump commands are completed at the moment when the PR executor reads
the command, and thus they do not enter the generator. The arithmetic operations commands
are executed when entering the PR executor; however, the execution time varies with the
computing duration and the next command cannot interrupt during computing. The PR executor
can consecutively complete at least 20 PR paths with interrupt commands (INS) (without delay
times ) within 1 ms. If there is a PR path that it has not completed within 1 ms, and a new PR
group is sent to the executor by the queue, the new PR group then replaces the previous PR
group. In other words, instead of executing the PR group that hasn‟t been completed, the
executor starts executing the new PR group. However, if a new PR group hasn‟t been sent to the
executor yet, the executor continues to execute the unfinished PR path.

Motion command generator
Motion commands include the Speed and Position commands. The PR executor sends this type
of command to the motion command generator. This generator has a buffer for temporarily
storing the next motion command and all motion commands are integrated here. Motion
commands can be executed as soon as they enter the generator. If another motion command
(with interrupt setting) also enters the generator, it is integrated with the current command in the
generator and the integration is based on the motion command settings. The settings include
whether multiple motion commands are sequence commands, and whether it is set with the
Overlap or Interrupt function. All integration varies with each PR path setting.
Sequence command
The configurable commands in PR path are the motion commands, which are the Position and
Speed commands. A sequence command is a motion command without an Overlap or Interrupt
function. The following command start to be executed only after the delay set in the previous
command. Regarding Position commands, the delay time starts to count after the target position
is reached. For Speed command, the delay time counting starts after the target speed is
reached.