System Manual Compact Systems
6 User Program
HI 800 141 E Rev. 2.02
Page 35 of 110
2. In
Multitasking Mode 2,
the unneeded duration of lower-priority user programs is distributed
among higher-priority user programs. In addition to the specified
Max. Duration for Each
Cycle [µs],
these user programs can use the portions of unneeded duration. This procedure
ensures high availability.
Four user programs are used in the example:
Prg 1
…
Prg 4
. The following priorities are
allocated to the user programs:
-
Prg 1
has the lowest priority, priority
x
-
Prg 2
and
Prg 3
have a medium priority, priority
y
-
Prg 4
has the highest priority, priority
z
z
y
y
x
y
t
y
x
x
Prg 1
Prg 3
y
Prg 2
y
Prg 4
z
z
First CPU cycle considered.
Second CPU cycle considered.
Third CPU cycle considered.
Max. Duration for Each Cycle [µs]
of
Prg 1
has
expired,
Prg 2
starts.
Max. Duration for Each Cycle [µs]
of
Prg 2
has
expired,
Prg 3
starts.
Max. Duration for Each Cycle [µs]
of
Prg 3
has
expired,
Prg 4
starts.
Max. Duration for Each Cycle [µs]
of
Prg 4
has
expired, completion of the first CPU cycle.
Completion of the
Prg 1
cycle,
Prg 2
is resumed.
The remaining duration is distributed to the
Max.
Duration for Each Cycle [µs]
of
Prg 2
and
Prg 3
(medium priority y) (arrows).
Prg 2
Max. Duration for Each Cycle [µs]
+
proportional remaining duration of
Prg 1
have
expired,
Prg 3
is resumed.
Prg 3
Max. Duration for Each Cycle [µs]
+
proportional remaining duration of
Prg 1
have
expired,
Prg 4
starts.
Max. Duration for Each Cycle [µs]
of
Prg 4
has
expired, completion of the first CPU cycle.
The next user program cycle of
Prg 1
starts.
Completion of
Prg 1
Max. Duration for Each
Cycle [µs]
,
Prg 2
resumes.
Completion of
Prg 2
Max. Duration for Each
Cycle [µs]
,
Prg 3
is resumed.
Completion of the
Prg 3
cycle,
Prg 4
is resumed.
The remaining duration is added to
Prg 4
(highest priority
z
).
Max. Duration for Each Cycle [µs]
of
Prg 4
+
remaining duration of
Prg 3
have expired,
completion of the third CPU cycle.
Figure 6: Multitasking Mode 2
Содержание HIMatrix F30
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