CAUTION: this information refers to an earlier version of the file format (version 1.2).

A ladder/diagram programming language program is a single file (type .LAD) that contains both editing (source) information and execution information (typically on RTE or compatible firmware).

A ladder program consists primarily of a header, then several sections of which the main ones are:

•table of structures, which are the user-defined data types.

•table of variables, i.e., the general variables of the program.

•table of blocks, i.e., the sub-routines in other programming languages;

•table of live changes, i.e., any embedded live changes files;

•table of strings;

•table of compressed strings.

In the block list, there is always a main block called MAIN and possibly additional blocks (comparable to sub-routines in other programming languages): each block contains a list of circuits that constitute the actual ladder program: each circuit in turn is a logically structured list of elements.

NOTE: all numeric data stored in this file are to be considered in little endian format (standard x86/x64).