Task Operation Sequence - Omron R88A-MCW151-DRT-E Operation Manual

Task Operation Sequence

5-6

Task Operation Sequence

Motion Sequence
Program task execution
sets which program to run automatically and at which priority. This can also
be accomplished by the RUNTYPE BASIC command. The current status can
be seen using the DIR command.
The allocation of the system tasks and the program tasks with the different
priorities over the available processing time is explained in the following sec-
tion. The MC Unit generates a fixed interrupt every 250 s, which result in
4 routines to be executed each millisecond. Each interrupt will start the next
routine.
Depending on the setting of the Servo Period (using the SERVO_PERIOD
parameter), the motion sequence is executed every 500 s or every 1000 s.
Routine 1
250
Servo Period 500 s
The tasks (simplified) of each individual routine is shown in the next table.
Routine 1
• Motion Sequence
• Program task execution (low pri-
ority)
Routine 3
• Motion Sequence (if period is
500 s)
• LEDs update
• Program task execution (high
priority)
The motion sequence which will be executed at the beginning of each Servo
Period will contain the following elements:
1. Transfer any moves from BASIC process buffers to motion buffers (see
5-3 Motion Execution).
2. Read digital inputs.
3. Load moves. (See note).
4. Calculate speed profile. (See note).
5. Calculate axis positions. (See note).
6. Execute position servo. For axis 0 this also includes the Servo Driver com-
munications. (See note).
7. Update outputs.
Note Each of these items will be performed for each axis in turn before moving on
to the next item.
There are three slots available for the BASIC tasks execution. The slots will
be allocated to the different tasks based on the task priorities. Tasks 3 and 2
have high priority and task 1 and 0 (command line) have low priority.
For each period (1 ms) the high priority tasks are always allocated the two
time slots for high priority (routine 2 and 3). Use this task for programs which
Routine 2 Routine 3
250 250
Servo Period 1000 s
• Low level serial communication
• Program task execution (high
priority)
• Communications
Host Link)
Section 5-6
Routine 4 ...
250
Time ( s
Routine 2
Routine 4
(DeviceNet,
)
93