Home / ABB / ABB Drives / ABB AC Drives / ABB ACS880 Drive / ABB ACS880 Drive Options Code / ABB ACS880 Drive +L516 FEN-21 Optional Code/Module (2 inputs (Resolver, TTL pulse encoder), 1 output)ABB ACS880 Drive +L516 FEN-21 Optional Code/Module (2 inputs (Resolver, TTL pulse encoder), 1 output)