Modify a PLC appearance style
There are 5 predefined PLC styles provided with AutoCAD Electrical, numbered 1 through 5. If one or more of these do not appeal to you or if you have a client with specific requirements not met by any of the 5 styles, you can pick one of the existing styles and modify it.
There are about 3 dozen symbols associated with each style. They are located in the jic1 subdirectory (or jic125 for the uniform 0.125 text height version). They carry the file name "HP?*.dwg" where "?" is the style number.
Create a PLC style
An easy way to create a PLC style is to copy the library symbols of an existing PLC style to one of the unused style numbers (6, 7, 8, or 9) and then edit each one to suit your needs.
For example, copy style 1 to style 6 by copying "\Documents and Settings\All Users\Documents\Autodesk\Acade {version}\libs\{library}\hp1*.dwg" to "\Documents and Settings\All Users\Documents\Autodesk\Acade {version}\libs\{library}\hp6*.dwg" (or, if you are using Windows Vista or Windows 7, copy "\Users\Public\Documents\Autodesk\Acade {version}\libs\{library}\hp1*.dwg" to "\Users\Public\Documents\Autodesk\Acade {version}\libs\{library}\hp6*.dwg"). Open the hp6*.dwg drawing files in AutoCAD and modify as required. To access your new style, select "6" in the style sub dialog box when you prepare to select and insert a new PLC module.
Add a new PLC style
The icon menu graphics that display for the various PLC styles are bitmap files saved to your \Program Files [(x86)]\Autodesk\Acade {version}\Acade\ folder where AutoCAD Electrical's Insert PLC and Drawing Properties tools can access them.
Note: If the resulting bitmap is too small or off-center, open the source drawing in AutoCAD again. Resize your AutoCAD graphics window so that it is more square. Center the image and resave. Repeat until you are satisfied with the result.