→LD - ladder diagram

According to German Wikipedia (https://de.wikipedia.org/wiki/Kontaktplan): Ladder diagram (abbreviation LD) is a method for programming the programmable logic controllers (→PLCs).
It is a graphical programming languaged standarized by →IEC-standard EN 61131-3. It is particularly suited for logic controllers. The representation is based on wiring diagrams.

In logi.CAD 3 use the LD-editor to create a ladder diagram. The LD-editor is not provided in all variants of logi.CAD 3.