AutoCAD Electrical 2004 uses a "project" concept to
pull together a collection of one to hundreds of interrelated schematic, panel,
wiring diagram drawings together. Each project is given a name and is
represented by a small ascii text file that lists all of the different AutoCAD
drawings that are to be treated as a single project set for component
tagging, cross-referencing, wire numbering, and BOM report generation.
For these inter-drawing functions to fully work,
AutoCAD Electrical needs to be able to access the complete drawing set.
Therefore, with a PDM system, instead of checking out individual
drawing documents, you would probably want to check out a project
set.