Free Form Ladder Diagram (FFLD) Editor

The FFLD Editor is a powerful graphical tool that enables you to enter and manage Ladder Diagrams according to the IECClosed"International Electrotechnical Commission" IEC is a not-for-profit, non-governmental international standards organization that prepares and publishes International Standards for all electrical, electronic and related technologies 61131-3 standard. This Editor enables free drawing and arrangement of FFLD items, and supports advanced graphic features such as:

Drag-and-drop operation

FFLD diagram components Related sections
Networks
Power rail and lines
Contacts and coils
Function blocks
Data In/Out
Jumps and RETURN
Using the FFLD toolbar
Selection grid
Moving and copying items

Run-time 

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

Networks

A program is entered as a list of independent networks. Networks are executed sequentially from the top to the bottom. The head of a network is drawn on a full row in the editor, grouping the following pieces of information:

  • The number of the network (from 1 to N)
  • (Optional) A label name used as a target for jump operations
  • (Optional) A directive for conditional compiling
  • (Optional) A multiple line description (comment)

No item can be put on a network header row. No line can go through it. The end of a program is marked with a special "End of module" row. Nothing can be inserted after this row.

       

Double-click on the header of a network to enter its label, directive (sometimes called pragmaClosedA compiler directive communicating additional "pragmatic" information. Pragmas are processed at compile time, not at run time. They pass information to the compiler) and description. Network headers are green, but they became blue when a directive is defined (see also Conditional Compiling for more details).

New networks can be inserted on empty rows.

When a network is selected, pressing "DEL" merges its content with the previous network. When the first network is selected, pressing "DEL" removes the network and its whole contents.

There cannot be two networks having the same label in a program. If such a situation occurs in the case of a copy operation, you will be prompted to either specify another label name for the new network, or remove the label on the new network.

You can also collapse/expand a network with the minus/plus sign located next to the Network number in the header.

       

Run-time

When your application is running, you can force and lock a variable or a contact directly in the editor with a double-click operation. For more information, see "Forcing a variable".

For more details on FFLD language, also refer to Free Form Ladder Diagram (FFLD).

Concept Link IconSee Also