5.10.2.1 Function RS485 X3Using this parameter the RS485 interface may be switched to PtP communication (pointto point) respectively the synchronization between DP master system and CPU may beset:Deactivated Deactivates the RS485 interface.PtP With this operating mode the PROFIBUSDP master is deactivated and the RS485interface acts as an interface for serialpoint-to-point communication. Here datamay be exchanged between two stationsby means of protocols.PROFIBUS DP async PROFIBUS DP master operation asyn-chronous to CPU cycle The RS485 inter-face is preset at default to PROFIBUS DPasync. Here CPU cycle and cycles ofevery VIPA PROFIBUS DP master runindependently.PROFIBUS DP syncIn The CPU is waiting for DP master inputdata.PROFIBUS DP syncOut The DP master system is waiting for CPUoutput data.PROFIBUS DP syncInOut CPU and DP master system are waiting oneach other and form thereby a cycle.Default: PROFIBUS DP async5.10.2.1.1 Synchronization between master system and CPUNormally the cycles of CPU and DP master run independently. The cycle time of the CPUis the time needed for one OB1 cycle and for reading respectively writing the inputsrespectively outputs. The cycle time of a DP master depends among others on thenumber of connected slaves and the baud rate, thus every plugged DP master has itsown cycle time. Due to the asynchronism of CPU and DP master the whole system getsrelatively high response times. The synchronization behavior between every VIPAPROFIBUS DP master and the CPU may be configured by means of a hardware configu-ration as shown above. The different modes for the synchronization are in the followingdescribed.In PROFIBUS DP SyncInOut mode CPU and DP master system are waiting on eachother and form thereby a cycle. Here the whole cycle is the sum of the longest DP mastercycle and CPU cycle. By this synchronization mode you receive global consistent in-/output data, since within the total cycle the same input and output data are handled suc-cessively by CPU and DP master system. If necessary the time of the Watchdog of thebus parameters should be increased at this mode.OverviewPROFIBUS DP SyncInOutVIPA System 300S+Deployment CPU 317-4PN23Setting VIPA specific CPU parameters > VIPA specific parametersHB140 | CPU | 317-4PN23 | en | 18-0158
