I need to create PDF/A conform files of technical drawings with Adobe Illustrator.
Are there any presets for saving PDF/A files? Or do I need Adobe Acrobat Pro for this?
It's not possible to generate PDF/A files directly in Illustrator, Photoshop, or InDesign (as of CS6), only in Acrobat Pro version 8.0 or newer, and Acrobat Distiller which comes with Acobat Pro. However, I believe there is a commercially sold Illustrator plug-in available, and other stand-alone conversion software.
Otherwise you open the AI file in Acrobat Pro and use the Preflight feature to generate a separate PDF/A-compliant file from it.
An alternative workflow might be the 'old-school' postscript export from Illustrator to Acrobat Distiller. Distiller has the PDF/A-1b profiles for CMYK and RGB. This also allows for automated PDF generation with Distiller lurking in the background: You save a postscript file from Illustrator (via the Print dialog, set Printer to 'Adobe PostScript File', and PPD to 'Adobe PDF 9.0') into a specific folder that Distiller is set to 'watch' and to automatically convert PDFs from PS files in there...
PDF/A is promoted by the 'PDF Association' based in Germany. A brochure with more details on the use of Acrobat Pro can be downloaded from their website: PDF/A in a Nutshell (2011) http://www.pdfa.org/wp-content/uploads/2011/08/PDFA-in-a-Nutshell_1b.pdf
The presets include the PDF/A selection.