Draw FBD Connection Lines

Click this button before inserting a new line.


  • The editor is used to terminate a connection line with a Boolean negation represented by a small circle:

    (* use of a negated link: Q is IN1 AND NOT IN2 *)

    To set or remove the Boolean negation, select the line and press the <Spacebar>.

  • Connection lines must always be drawn in the direction of the data flow: from an output pin to an input pin.
  • The FBD editor automatically selects the best routing for the new line.
  • Connection lines indicate a data flow between these possible objects:

  • Line is colored in red when the two linked items are not the same type.

Tool

Button

Description

Block

See the help for the block for the description of its input and output pins, and the expected data types for the coherence of the diagram.

Coil

A coil must be connected to a Boolean data flow from it's left-hand side.

It is not mandatory that a coil be connected on its right-hand side.

Contact

A contact must be connected to a Boolean data flow on both its left- and right-hand side.

Jump

A jump must be connected to a Boolean data flow from its left-hand side.

Left power rail

Left power rails represent a TRUE state.

It can be connected to an unlimited number of objects on their right-hand side. 

OR rail

This type of rail collects several Boolean data flows for an "OR" operation, in order to insert parallel contacts (e.g., Ladder Diagrams).

  • An OR may have several connections on both its left- and right-hand side.
  • All connected data flows must be Boolean.

Right power rail

A right power rail is an element of the FFLD language, and is commonly used for terminating Boolean data flows.

  • It has an unlimited number of connections on its left-hand side.
  • It is not mandatory to connect coils to power rails.

Variable

A variable can be connected on its right-hand side (to initiate a flow) or on their left-hand side to force the variable, if it is not read-only.

The flow must fit the data type of the variable. 


  • Connection lines automatically move and follow FBD elements (1) and you can also manually specify the corners.
    Double-click on the line to show a handle (2) which can be repositioned (3).