The Y-Link comprises:

• Two IM 153-2 interface modules
• One Y-Coupler
• One BM IM/IM bus module
• One BM Y-Coupler bus module

Snapped on mounting rails for setup with active bus modules.

Configuration options and limitations

A redundant PROFIBUS DP master system can be extended by means of Y-Links in the following way:

• The number of Y-Links on a redundant DP master system is only limited by the maximum number of stations. The maximum number of connectable slaves depends on the length of the user data and configuration message frames. The total length of each may not exceed 244 byte (see slave technical specifications).
  Generally, the following applies:
  • max. 64 stations in the lower-level DP master system
  • max. 236 slots in the lower-level DP master system
• Y-Link configuration and user data message frames comprise message frame contents of the lower-level slaves. Therefore, the maximum message frame length is 244 byte.
• Direct communication and equidistance not possible in the lower-level master system