A. Reiners, M. Zechmeister, J. Caballero, I. Ribas, J. Morales, S. Jeffers, P. Schöfer, L. Tal-Or, A. Quirrenbach, P. Amado and 163 other author(s). (2017)cite arxiv:1711.06576Comment: accepted for publication in A&A, 13 pages plus 40 pages spectral atlas, first 10 atlas pages are reduced in quality to fit arXiv size limit; one CARMENES spectrum for each of the 324 stars is published in electronic format at http://carmenes.cab.inta-csic.es/.