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This note replaces the following section of the Pro.chm help file (workbench user's guide):

In the workbench/ project manager/ Link Archi. view/ Resource properties /settings / Advanced chapter

SFC dynamic behavior limits

These are options which determine the amount of memory, allocated by the target at initialization time, to manage SFC Dynamic behavior (i.e. token moving).

The amount of allocated memory is calculated as a linear relation with the number of SFC POUs:

NbElmt = GainFactor * NbOfSFC + OffsetFactor

Alloc Mem (bytes) = N * NbElmt * sizeof(typVa)

Where:

• N = 5 (constant linked to SFC engine design).
• typVa = 16 bits in the medium memory model or 32 bits in the large memory model.
• NbElmt represents, for each executed cycle, the maximum number of transitions that can be valid. That is to say transitions with at least one of their previous steps being active.

A simpler, but more approximate definition is:

• The maximum number of steps that can be active.
• The maximum number of actions that can be executed.

Here, an action refers to an N, P1 or P0 action linked to a step.

If the available memory is not enough at a specific moment:

• If generated with check mode (ITGTDEF_SFCEVOCHECK defined in dsys0def.h), The Target Kernel generates a warning to signal an SFC token moving error, or an action execution error and the resource is set in ERROR mode (i.e. cycles are no more executed).
• Otherwise, Kernel behavior may be unpredictable.

In  target versions 4.03 and older, the resource is not set in ERROR mode.

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