Function Block Diagram (FBD) Editor

The FBD Editor is a graphic tool used to enter and manage Function Block Diagrams according to the IEC 61131-3 standard.

  • The editor supports advanced graphic features such as drag-and-drop, object resizing, and connection line routing features to rapidly and freely arrange the elements of a diagram.
  • Insert in an FBD diagram graphic elements of the FFLD (Ladder Diagram) language (e.g., contacts and coils).

FBD Diagram Components

Related Sections

Function blocks

Variable tags

Comment texts

Corners

Network breaks

Labels

Jumps

Use of ST instructions

Using the FBD toolbar

Selecting Function Blocks

Drawing connection lines

Selecting and entering variables and FB instances

Viewing the diagram

Moving or copying parts of the diagram

Inserting an object on a line

Resizing objects

Bookmarks

FFLD Components

 

FFLD Contacts and Coils

"OR" vertical rail

Power rails

 

  • When a contact or a coil is selected, press the Spacebar to change its type (e.g., normal, negated, pulse).

Boolean connections can be negative at the entry of a block.

  1. Select the Boolean connection

    Connections in FBD Programs

  2. Press the Spacebar (a small circle is displayed)

    Toggle Connection in FBD Programs

Execution order can be displayed.

Data flow is executed from top left to bottom right (CTRL+d shows the execution order).

Figure 1: Execution Order on FBD

Concept Link IconSee Also