Serial Plc Link Response Performance - Omron CP1L CPU UNIT - 06-2007 Operation Manual

Computing the Cycle Time
(Interrupt signal retrieval)
Interrupt task execution
Cyclic task execution
(main program)
Scheduled Interrupt Tasks
2-7-9

Serial PLC Link Response Performance

executed in order of priority after the current interrupt task has completed
execution and the software interrupt response time has elapsed.
The interrupt response time of input interrupt tasks is calculated as follows:
Interrupt response time = Input ON delay + Software interrupt response time
Input
Input ON delay
Software interrupt response time
Input interrupt task
response time
The time from completing the ladder program in the input
interrupt task until returning to cyclic task execution is 60 µs.
The interrupt response time of scheduled interrupt tasks is the time taken
from after the scheduled time specified by the MSKS(690) instruction has
elapsed until the interrupt task has actually been executed. The length of the
interrupt response time for scheduled interrupt tasks is 1 ms max. There is
also an error of 80 µ s in the time to the first scheduled interrupt (0.5 ms min.).
Note Scheduled interrupt tasks can be executed during execution of the user pro-
gram (even while an instruction is being executed by stopping the execution of
an instruction), I/O refresh, peripheral servicing, or overseeing. The interrupt
response time is not affected by which of the above processing operations
during which the scheduled interrupt time occurs. Scheduled interrupts, how-
ever, are not executed during execution of other interrupt tasks even if the
interrupt conditions are satisfied. Instead, the interrupts are executed in order
of priority after the current interrupt task has completed execution and the
software interrupt response time has elapsed.
Scheduled interrupt task
The response times for CPU Units connected via a Serial PLC Link (master to
slave or slave to master) can be calculated as shown below. If a PT is in the
Serial PLC Link, however, the amount of communications data will not be
fixed and the values will change.
• Maximum I/O response time (not including hardware delay) =
Master cycle time + Communications cycle time + Slave cycle time + 4 ms
• Minimum I/O response time (not including hardware delay) =
Slave communications time + 0.8 ms
Return time from
Ladder program
input interrupt task
execution time
Scheduled interrupt time
Internal timer
Software interrupt response time
Section 2-7
Next interrupt signal
can be accepted.
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