Lenze PLC Designer PLC Designer (R2-x) - Manual (Page 72)

L-force | PLC Designer
What is What in PLC Designer
70 DMS 3.2 EN 02/2011 TD29

4.2.4 Function Block Diagram (FBD)...
The Function Block Diagram is a graphically oriented programming language. It works
with a list of networks whereby each network contains a structure which represents
either a logical or arithmetic expression, the call of a function block, a jump, or a
return instruction.
Example of a network in the Function Block Diagram
4.2.5 The Continuous Function Chart (CFC)...
The continuous function chart bases on the Function Block Diagram language.
However it does not operate with networks, but rather with freely placeable elements.
This allows feedback, for example.
Example of a network in the continuous function chart editor
4.2.6 Ladder Diagram (LD)...
The Ladder Diagram is also a graphics oriented programming language which
approaches the structure of an electric circuit.
On the one hand, the Ladder Diagram is suitable for constructing logical switches, on
the other hand one can also create networks as in FBD. Therefore the LD is very useful
for controlling the call of other POUs.
The Ladder Diagram consists of a series of networks. A network is limited on the left
and right sides by a left and right vertical current line. In the middle is a circuit
diagram made up of contacts, coils, and connecting lines.