Action blocks in FBD
Use an →action block in order to control actions within a step sequence (an →SFC network). The control of the action is expressed by the action qualifier that is specified within the action block.
Several action blocks are allowed per SFC network. See the notes under "SFC elements in drawing field" how to create/use SFC networks efficiently and correctly.
Lines visualize the connections to the other FBD-elements in the drawing field.
Representation
Examples for an action block:
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The action block contains:
with the left field: the action qualifier – e.g. N or L (with the duration T#1s)
The action qualifiers L, D, SD, DS, SL and PN demand a duration literal or a variable of data type TIME. See "Creating or editing action blocks in FBD" on how to change the action qualifier and specify a duration.with the right field: the editor-wide valid action name – e.g. A0 or A1
Observe that it is possible to use the same action name within several action blocks. Subsequently, it is common that the different action blocks are connected to different steps.
The action name represents a Boolean, local variable with the same name that is listed within the list of the declared variables. You are able to use this action variable – such as a →constant Boolean variable – within →value fields (e.g. for assignments) in order to inquire the current state of the action variable. Within cycles in which the action is executed, this variable has the value TRUE (or an equivalent).
The input of the action block is located on the left edge, the output on the right edge. The data type for in-/output is always the elementary data type BOOL.
Usually, the input of the action block is connected to the output of a →step. But you are able to connect the input of an action block with the output of another FBD-element as well, as long as the →data type matches.
The output of the action block is connected with the input of a different FBD-element – its data type must match as well. Example: The output of the action block is connected to the EN input of a block call. logi.cals recommends you to create complex statements as separat block call and to connect the actin block with the EN inpit of this block call.
An action block with the action qualifier N behaves as a value field with a Boolean, local →Variable.
Depending on the configuration of your logi.CAD 3 version, the FBD-editor and its elements might be displayed differently in your logi.CAD 3 version than illustrated in the IDE documentation. This is the case, if logi.cals or the system integrator has changed the styles for the FBD-editor. Subsequently, the illustration in the IDE documentation are symbolic images and the representation in your logi.CAD 3 version takes precedence for the valid representation. In case of doubts, please contact logi.cals or your system integrator.
logi.cals recommends that you and/or your system integrator do not use yellow shades when designing FBD-elements because the color "Yellow" is used for tracking safe signals when developing safety-related applications. logi.CAD 3 does not check if colors are already used elsewhere. So the use of the yellow shades by you and/or your system integrator could have the consequence that "yellow" might also identify a non-safe logic as well.
Actions for action blocks
Page:Moving FBD-elements