Structured Ladder/Fbd; Standard Format - Mitsubishi Electric MELSEC Q Series Programming Manual

5.2

Structured Ladder/FBD

The structured ladder/FBD is a graphic language for writing programs using ladder symbols such as contacts, coils, functions,
and function blocks.

Standard format

Ladder block label
Left power rail
In the structured ladder/FBD language, units of ladder blocks are used for programming.
For structured ladder, connect the left power rail and ladder symbols with lines.
For FBD, connect the ladder symbols with lines according to the flow of data or signals without connecting with the left power
rail.
5 WRITING PROGRAMS
86
5.2 Structured Ladder/FBD
Contact
Function
Coil
Function block
Input variables Output variables