ABB ACS480-04-033A-4+K491 ACS480-04-033A-4 ACS480 drive with Modbus TCP. ABB ACS480-04-033A-4+K491 is an ACS480 general-purpose drive rated 380-480 V AC, three-phase, factory configured with Modbus TCP communication (FMBT-21). It is suitable for pumps, fans, compressors, conveyors and OEM control panels requiring direct PLC or industrial-network integration.