It is represented by an X in the lower right corner of the respective step box.Īction Action_AS1 is associated to step AS1 as a step action (left), or as an IEC action with qualifier N (right). The action is associated to a step via an entry in the Step exit field of the step properties. However, this execution will not be done in the same, but at the beginning of the subsequent cycle. It is represented by a small triangle in the upper right corner of the respective step box.Īn exit action will be executed once when the step becomes deactivated. The action is associated to a step via an entry in the Step active field of the step properties. However, in contrast to an IEC step action (see above) it is not executed again when it is deactivated and cannot get assigned qualifiers. This type of step action will be processed when the step has become active and after a possible step entry action of this step has been processed. It is represented by an E in the lower left corner of the respective step box. The action is associated to a step via an entry in the Step entry field of the step properties. This type of step action will be processed as soon as the step has become active and before the step active action. IEC conforming step action list associated to a step: The actions have to be available in the project and be inserted with a unique action name (for example, plc_prg.a1). The position of the new action depends on the current cursor position and the command. You can associate one or multiple actions with a step. O IEC step actions are associated to a step via the Insert action association command. In the left part, it shows the action qualifier, in the right part the action name. O An IEC step action is represented by a bipartite box connected to the right of a step via a connection line. This is not the case with the normal step actions. This permits that, even if the action is called also by another step, the action is executed always only once at a time. O A further difference to the normal step actions is that each IEC step action is provided with a control flag. O Different qualifiers can be used for IEC step actions in contrast to a normal step action. In case of assigning multiple actions to a step, the action list will be executed from top to bottom. This is an action according to the IEC61131-3 standard which will be processed according to its qualifier when the step becomes active, and then a second time when it becomes deactivated. The IEC conforming and the IEC extending step actions are described in the following paragraphs. Transition object (multiple use transition): NOTE: Transitions which consist of a transition or a property object are indicated by a small triangle in the upper right corner of the rectangle. NOTE: If a transition produces multiple statements, assign the desired expression to a transition variable. O multiple statements with arbitrary code The object like an inline transition can contain the following elements: (This allows multiple use of transitions see for example condition_xy in the figures below.) Replace the default transition name by the name of a transition ( ) or property object ( ) available in the project. Using a separate transition or property object You cannot specify programs, function blocks, or assignments here. O instruction having a boolean result (example: (i<100) AND b). Replace the default transition name by one of the following elements: After inserting it has a default name, Trans, whereby n is a running number.Įxample for step and subsequent transition: The transition is represented by a small rectangle. The box frame of the first step within an SFC, the initial step, is double-lined. It is connected to the preceding and subsequent transition by a line. Steps and transitions can also be inserted in combination, via command Insert step-transition ( ) or Insert step-transition after ( ) from the toolbar.Ī step is represented by a box primarily containing an automatically generated step name. To insert a single step or a single transition, execute the command Step or Transition from the ToolBox. The following elements are available and are described in this chapter: You can insert the graphic elements usable for programming in the SFC editor window by executing the commands from the SFC menu.įor information on working in the editor, refer to the description in the chapter Working in the SFC Editor
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