SFC Element Properties

You edit the properties of an SFC element in the Properties view. Click View ‣ Element properties to open this view. The properties to be displayed depend on the currently selected element.

Note

The properties that are displayed in the SFC diagram next to the element depend on the settings in the View tab of the SFC editor options.

General

Property Value description
Name Element name, by default “<element><consecutive number>”, for example step name “Step0”, “Step1”, branch name “Branch0”, etc.
Comment Element comment in text, for example “counter reset”. You can insert line breaks by pressing Ctrl+Enter.
Symbol

For each SFC element, CODESYS declares an implicit variable with the same name as the element.

The configuration determines whether this flag variable should be exported to the symbol configuration and which access rights for the symbol should be applied in the PLC.

  • No access: The symbol is exported to the symbol configuration but cannot be accessed from the PLC.
  • Read: The symbol is exported to the symbol configuration and can be read from the PLC.
  • Write: The symbol is exported to the symbol configuration and can be written from the PLC.
  • Read/Write: Combination of read and write.
  • Empty: A symbol is not exported to the symbol configuration.

Specific

Property Value description
Init step

: This option is activated only for the defined initial step. By default, this is the first step in an SFC diagram.

Note: If you activate this property for another step, then it must be deactivated in the previous step to prevent compilation errors.
Duplicate when copying

This option is available for steps that contain a step action (entry action, main action, or exit action), and for transitions that are linked to a transition object.

: When copying the step or transition, a new object is created for each called action or transition. It contains a copy of the implementation code of the copied object.

: When copying a step or transition, the link to the called object is retained for the respective action or transition. No new objects are generated. The source and the copies of the step or transition call the same action or transition.

Times

  • Minimum active
  • Maximum active

Minimum time that the step is active, even when the subsequent transition is TRUE.

Maximum time that the step can be active. If this time is exceeded, then CODESYS sets the SFCError implicit variable to TRUE.

Times according to IEC syntax (for example t#8s) or the TIME variable; default: t#0s.

Actions

  • Entry action
  • Step action
  • Exit action
  • Entry action: CODESYS executes these actions after activating the step.
  • Step action: CODESYS executes this action when the step is active and any entry actions have already been processed.
  • Exit action: CODESYS executes this action in the subsequent cycle when the step is deactivated.

Please note the processing sequence.

Note

When using the respective implicit SFC variables and flags, you receive information about the status of a step or an action or about timeouts.

See also