300 Rockwell Automation Publication 2198-UM004A-EN-P - October 2019
Chapter 11 Motion Control in PR Mode
PR Execution Process
The drive will update the command status every 1 ms. Figure 130 illustrates the
PR procedure execution flow and how the servo drive deals with PR commands.
Once a PR procedure is triggered, it will go through three units, which are PR
queue, PR executor, and motion command generator.
Figure 130 - PR Arrangement Procedure of the Drive
• Trigger mechanism: There are three trigger methods. A PR procedure will
be executed as long as a trigger signal is received. When two different
trigger methods are used for one PR procedure within the same ms, the
priority is as follows: (1) DI trigger (DI.CTRG); (2) ID300 (P5.007)
PRCmdTrigger; (3) ID386 (P5.098) EventRisingEdgePRNumber; (4)
ID387 (P5.099) EventFallingEdgePRNumber. Within this ms, commands
with higher priority will be executed first and then the lower priority
commands in order. If three trigger commands are generated in the same
ms, the third will not be issued to the PR queue.
• PR Queue: The triggered PR command is the lead PR. The PR group it
leads will go into the PR queue to wait for the arrangement. In each ms, the
servo drive will send the lead PR and the PR group it leads to the PR
executor no matter whether a PR command is being executed. Therefore,
as long as a PR command 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 will be replaced immediately. If a PR group
includes motion commands, such as speed commands and position
commands, then the PR executor will send them to the motion command
generator. PR commands with write or jump commands will be completed
High
Low
DI.CTRG P5.007 Event(↑) Event(↓)
PR queue
• Every 1 ms, issues the waiting lead PR to PR executor no matter whether the
executor has completed the commands or not.
• New lead PR replaces the PR in the executor.
PR executor
• Sends the motion commands to the generator (Speed Cmd, Position
Cmd).
•
Completes jump, write, and arithmetic operations commands.
• Within 1 ms, it completes at least 20 consecutive commands with interruption functions
and without delay (If arithmetic operations which cannot be interrupted are
included, duration is determined by the operation time and will be the last
command in 1 ms).
Motion command generator
• Integrates multiple commands (Sequence, interrupt, or overlap commands).
• Output the integrated motion commands.
Time
Speed
Trigger Mechanism Priority
ID300 (P5.007) = PRCmdTrigger
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