RSLogix is a PLC programming software package for programming various Allen-Bradley PLCs. This program has an output function that can write the I/O information out to an ASCII file. AutoCAD Electrical toolset imports this information and creates a regular spreadsheet from the data that can then be used to create PLC drawing files.
Using the RSLogix 500 Import dialog box, you can omit PLC cards, reserve future locations for PLC cards in drawings, and browse to select a PLC code from the PLC database. Once you modify the .eas file and apply the PLC data to categories you can save the data into a PLC import spreadsheet that is used to create the PLC drawing files.