11.7 PROFIBUS installation guidelinesn A PROFIBUS DP network may only be built up in linear structure.n PROFIBUS DP consists of minimum one segment with at least one master and oneslave.n A master has always been deployed together with a CPU.n PROFIBUS supports max. 126 participants.n Per segment a max. of 32 participants is permitted.n The max. segment length depends on the transfer rate:9.6 ... 187.5bit/s ® 1000m500kbit/s ® 400m1.5Mbit/s ® 200m3 ... 12Mbit/s ® 100mn Max. 10 segments may be built up. The segments are connected via repeaters. Everyrepeater counts for one participant.n The bus respectively a segment is to be terminated at both ends.n All participants are communicating with the same transfer rate. The slaves adjustthemselves automatically on the transfer rate.n As transfer medium PROFIBUS uses an isolated twisted-pair cable based upon theRS485 interface.n The RS485 interface is working with voltage differences. Though it is less irritablefrom influences than a voltage or a current interface. You are able to configure thenetwork as well linear as in a tree structure.n Max. 32 participants per segment are permitted. Within a segment the members arelinear connected. The segments are connected via repeaters. The maximum segmentlength depends on the transfer rate.n PROFIBUS DP uses a transfer rate between 9.6kbit/s and 12Mbit/s, the slaves arefollowing automatically. All participants are communicating with the same transferrate.n The bus structure under RS485 allows an easy connection res. disconnection of sta-tions as well as starting the system step by step. Later expansions don’t have anyinfluence on stations that are already integrated. The system realizes automatically ifone partner had a fail down or is new in the network.The following picture illustrates the terminating resistors of the respective start and endstation.PROFIBUS in generalTransfer mediumBus connectionVIPA System SLIO Option: Deployment PROFIBUS communicationPROFIBUS installation guidelinesHB300 | CPU | 013-CCF0R00 | en | 19-30 263
