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Comparison between AS-i Installation and other IP67 fieldbus systems

Other fieldbus systemsAS-Interface                                                                    



  • Mostly line structure
  • Any structure: tree, line, star or mixed
  • No stub cables
  • Any stub cables
  • Shielded, twisted cables (exception: IO-Link)
  • Unshielded, non-twisted cable
  • Data and power separate (for IO-Link partially in the same round cable)
  • Data and power on the same cable
  • Installation only via plug/socket
  • Installation using flat cable, M12 plugs or mixed
  • Many cables of various lengths usually needed
  • Simply cut flat cable to the required length from the spool
  • Coarser granularity, generally at least 8 in-/outputs per module
  • Fine granularity: Modules with 1, 2, 4, 8, 16 I/Os available; the more modules or the finer the granularity, the greater the cost advantage when using penetration technology
  • 24 Volt power distribution: M12 (Ø < 0.4 mm²) usually with many fuses and single leads from the control cabinet or through ¾ inch plugs
  • 24 Volt power distribution: With centralized feeding over black flat cable (Ø 1.5/2.5 mm²); if needed, passive distributors in IP67 for changing to round cable with smaller conductor cross-section are available
  • No special power supply needed
  • Up to 50 m cable length no special power supply needed (24V AS-i)