May I make my own PROFIBUS cables?

Yes, you may. Just be sure to use PROFIBUS specific cable (Belden 3079a or equivalent) and proper connectors designed specifically for PROFIBUS DP.  At least two of the connectors (one at each end of the cable) will require PROFIBUS termination switches.

Related Keywords:

PROFIBUS Siemens connectors PDPM PDPS cable PDPMV1