HIMA HIMatrix F30, Системное руководство

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System Manual Compact Systems 6 User Program
HI 800 141 E Rev. 2.02 Page 33 of 110

The sum of the Max. Duration for Each Cycle [µs] parameters in all user programs must not
exceed the resource watchdog time. Make sure that sufficient reserve is planned for
processing the remaining system tasks.

The sum of the Max. Duration for Each Cycle [µs] parameters in all user programs must be
large enough to ensure that sufficient reserve is available to maintain the target cycle time.

The Program ID s of all user programs must be unique.
During verification and code generation, SILworX monitors that these rules are observed. These
rules must also be observed when modifying the parameters online.
SILworX uses these parameters to calculate the user program watchdog time:
User program watchdog time =
watchdog time * maximum number of cycles
i
The sequence control for executing the user programs is run in cycles of 250 µs. For this
reason, the values set for
Max. Duration For Each Cycle [µs] can be exceeded or under-run by
up to 250 µs.
Usually, the individual user programs operate interference-free and independently to one
another. However, reciprocal influence can be caused by:

Use of the same global variables in several user programs.

Unpredictably long runtimes can occur in individual user programs if a limit is not configured
with Max. Duration for Each Cycle [µs] .
NOTE
Reciprocal influence of user programs is possible!
The use of the same global variables in several user programs can lead to a variety of
consequences caused by the reciprocal influence among the user programs.

Carefully plan the use of the same global variables in several user programs.

Use the cross-references in SILworX to check the use of global data. Global data may
only be assigned values in one location, either in a user program or from the
hardware!
i
HIMA recommends to set the Max. Duration for each Cycle [µs] parameter to an appropriate
value ≠ 0. This ensures that a user program with an excessively long runtime is stopped during
the current CPU cycle and resumed in the next CPU cycle without affecting the other user
programs.
Otherwise, an unusually long runtime for one or several user programs can cause the target
cycle time, or even the resource watchdog time, to be exceeded, thus leading to an error stop
of the controller.
The operating system defines in which order the user programs are executed in accordance
with the following scheme:

User programs with lower priority are executed before user programs with higher priority.

If the user programs have the same priority, the system executes them in ascending order of
the Program ID s.
This order is also followed when starting and stopping the user program during the start and
stop of the PES, respectively.
6.2.2 Multitasking Mode
Three operation modes exist for multitasking. These modes differ in how the time that is not
needed for executing the CPU cycle of the user programs is used. One of these three modes
can be selected for every resource.